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Breast Cancer Screening Knowledge Exchange Virtual Event - “What We Heard” Summary Report

Table of Contents

Executive Summary

Background

In June 2023, PHAC announced its intention to host a knowledge exchange event to bring together experts, partners, those with lived experiences, and stakeholders, to discuss the current state of the science, including knowledge gaps, related to breast cancer screening. This Knowledge Exchange Event (KEE) was organized and convened by the Public Health Agency of Canada (PHAC) with support from Health Canada, the Canadian Institutes of Health Research, the Canadian Partnership Against Cancer, the Canadian Cancer Society, the Canadian Breast Cancer Screening Network, and Dr. Aisha Lofters. The Canadian Public Health Association (CPHA) was contracted as the event coordinator and provided advice on planning and logistics.

Purpose

The event was intended to inform the Canadian Task Force on Preventive Health Care (CTFPHC)’s breast cancer screening guideline update and foster collaboration between stakeholders to advance issues related to breast cancer screening in Canada.

Event

The Breast Cancer Screening KEE was held on September 26–27, 2023, with participants from a variety of sectors and regions across Canada. This event included presentations from 15 different stakeholders across three main areas: breast cancer screening guidelines in Canada and abroad, stakeholder perspectives, and research and innovation for advancing screening practices (including current challenges and looking to the future). Panel presentations were followed by Q&A sessions, as well as roundtable discussions with audience members.

Discussion Highlights

Roundtable discussions focused on the following aspects of breast cancer screening in Canada:

Final Reflections

Participants expressed the following final reflections:

1.0 Background

1.1 About this Report

This report provides a summary of panelist and participant contributions from a Knowledge Exchange Event (KEE) hosted by the Public Health Agency of Canada (PHAC) in September 2023. The KEE brought together experts, partners, those with lived experiences, and other stakeholders to discuss the current state of the science, including knowledge gaps, related to breast cancer screening. The outcomes from the KEE were synthesized and analyzed in this report.

The Canadian Public Health Association (CPHA) was contracted by PHAC to act as the event coordinator, provide advice on planning and logistics, and host the KEE. This report was funded by PHAC and prepared by CPHA in collaboration with PHAC. It does not provide an overall representation of public opinion, institutional policies or positions, nor that of a randomly selected population sample. Rather, it presents a synthesis of the ideas expressed by the people who participated in the KEE. This report does not necessarily reflect the opinions of CPHA or PHAC.

1.2 Acknowledgement

Thank you to everyone who took the time to participate in this KEE. Your contributions and insights will inform the Government of Canada’s efforts to improve the health of people living in Canada.

1.3 Context

In June 2023, the Honourable Jean-Yves Duclos, then Minister of Health, announced PHAC’s intention to host a KEE related to breast cancer screening. The Breast Cancer Screening Knowledge Exchange Virtual Event aimed to:

This two-day virtual KEE created an accessible, safe, and inclusive space for all participants to be treated with dignity and respect, during which diverse perspectives and experiences were expressed and appreciated. This was accomplished by observing the following engagement strategies during discussions:

Refer to Appendix A for more details about the Event Program.

1.4 Process

To assist in planning this event, PHAC established an Advisory Planning Committee, which included representatives from Health Canada, the Canadian Institutes of Health Research (CIHR), the Canadian Partnership Against Cancer (CPAC), the Canadian Cancer Society, and the Canadian Breast Cancer Screening Network (CBCSN). Dr. Aisha Lofters also provided valuable feedback to key meeting documents.

The KEE was held on September 26–27, 2023, with participants from a variety of sectors and regions across Canada. This event included presentations from 15 different stakeholders across three main areas: breast cancer screening guidelines in Canada and abroad, stakeholder perspectives, and research and innovation for advancing screening practices (including current challenges and looking to the future). After each panel, participants were encouraged to ask questions and share their views on the various topics presented either verbally or by using the Q&A chat function in Zoom.

To ensure accessibility, French/English simultaneous interpretation and closed captioning were provided for each session, and low-vision participants were provided with materials in advance. The KEE was hosted by using the Zoom platform, and was facilitated by NIVA Inc. team member, Ms. Julie Desmarais, contracted by CPHA.

The KEE Advisory Planning Committee established the list of panelists and participants to be invited to the KEE based on a variety of criteria and methods, including their leadership and subject matter expertise in the breast cancer screening sector. Panelists and participants included people with lived experience, Canadian and international experts, health professionals, academics and researchers, representatives from patient advocacy groups, Indigenous and racialized communities, non-governmental organizations, as well as various provinces and territories.

Over 100 key stakeholders were invited to attend and approximately 70 of them attended both days. The Honourable Ya'ara Saks, Minister of Mental Health and Addictions and Associate Minister of Health, and PHAC senior officials also participated in the KEE.

2.0 Panels and Presentations

Participants heard presentations from various stakeholders. Panel presentations were followed by Q&A sessions as well as roundtable discussions with audience members. Summaries of all presentations and highlights from all live roundtable discussions and Q&A chat discussions are provided in this section.

2.1 Setting the Stage – Breast Cancer Screening Guidelines in Canada and Abroad

This panel showcased the experiences of groups developing breast cancer screening guidelines in Canada and abroad.

2.1.1 Canadian Task Force on Preventive Health Care (CTFPHC)

Presented by Drs. Guylène Thériault and Ahmed Abou-Setta (Canadian Task Force on Preventive Health Care)

The panelists’ presentation was entitled, “Breast Cancer Screening: Update to the CTFPHC 2018 guideline.”

Key highlights of the presentation included:

The process that the Canadian Task Force on Preventive Health Care (CTFPHC) is using to update their 2018 Breast Cancer Screening Guideline was presented. When the Breast Cancer Screening Guideline was last updated in 2018, the recommendations were based on an overview of systematic reviews of randomized trials as well as patients’ values and preferences. The 2018 breast cancer screening recommendations were as follows:

The guideline also stated that women in the age range of 40 to 49 may choose to undergo screening based on their personal values and preferences. In such cases, healthcare providers should actively participate in shared decision-making with women expressing an interest in screening. In both age ranges, the decision to undergo screening is conditional on the relative value that a woman places on possible benefits and harms from screening, shaped through shared decision-making with a healthcare provider.

The CTFPHC decided to update the current guideline in February 2023 (with an expedited timeline since June 2023) and the update will consider a variety of data sources, including:

In addition, the CTFPHC received a total of 145 documents (including 88 peer-reviewed publications) from 19 individuals and nine organizations through its online portal, which was open during the month of August 2023. Publications will be reviewed for inclusion in the systematic reviews currently underway.

Data derived from the various sources is needed in absolute numbers to provide frontline clinicians with breast cancer screening recommendations and to inform and equip Canadian women to decide whether they want to participate in screening or not.

The three main questions leading the update of breast cancer screening guidelines are:

  1. What are the benefits and harms of different mammography screening strategies vs. no screening in women aged 40 and older, and do benefits and harms differ based on population characteristics (age, breast density, race and ethnicity, socio-economic status, availability of mammography screening, family history)?
  2. What are the comparative benefits and harms of different mammographic breast cancer screening strategies in women aged 40 and older, and do comparative benefits and harms differ based on population characteristics?
  3. What is the relative importance placed by patients on the potential benefits and harms of breast cancer screening by mammography?

The clinical outcomes being considered for the guideline are:

The CTFPHC’s next steps include:

2.1.2 U.S. Preventive Services Task Force (USPSTF)

Presented by Dr. Wanda Nicholson (U.S. Preventive Services Task Force)

The panelist’s presentation was entitled “U.S. Preventive Services Task Force: Screening for Breast Cancer.”

Key highlights of the presentation include:

This presentation was focused on the draft update of the U.S. Preventive Services Task Force (USPSTF) Breast Cancer Screening Guidelines. Breast cancer is the second most common cancer and second most common cause of cancer death among American women. In 2023, it is estimated that there will be 297,790 new cases of breast cancer, with 43,170 women who will die of the disease. Black women are 40% more likely to die from breast cancer despite similar incidence among Non-Hispanic White and Non-Hispanic Black women.

Recommendations:

The 2016 U.S. Preventive Services Task Force (USPSTF) Breast Cancer Screening Recommendations stated the following:

In May 2023, the USPSTF published draft breast cancer screening recommendations based on evidence of the benefits and harms for screening pertaining to the age to start and stop screening and the screening interval and included clinical trials, studies, and collaborative modelling. The specific draft recommendations are:

For women ages 40–74 years, biennial screening mammography is recommended.

The following resources were used to develop these recommendations:

Addressing inequities:

To achieve the benefit of screening and mitigate disparities in breast cancer mortality by race and ethnicity, it is important that all persons with abnormal screening mammography receive equitable and appropriate follow-up evaluation as well as additional testing (including biopsies), and that those diagnosed receive effective treatment. Studies have identified disparities in follow-up after screening for Black, Hispanic, and Asian women, along with disparities in breast cancer treatment for Black women. Improvements are needed across the entire spectrum of breast cancer care to help mitigate inequities. For instance, starting screening at age 40 is a first step in addressing the higher mortality from breast cancer in Black women.

Research gaps:

2.1.3 Alberta Health Services

Presented by Mr. James Newsome (Program Innovation & Integration, Alberta Health Services Screening Programs)

The panelist’s presentation was entitled “Alberta Breast Cancer Screening Clinical Practice Guideline 2022 Update.”

Key highlights of the presentation include:

The focus of this presentation was the recent update of the Alberta Breast Cancer Screening Clinical Practice Guideline (CPG). The Guideline Committee was funded by the Alberta Medical Association’s Accelerating Change Transformation Team (ACTT). Committee members included family physicians, radiologists, mammography technologists, medical oncologists, surgeons, public representatives, nurse practitioners, public health and preventive medicine physicians, epidemiologists, and breast cancer screening program experts (including external reviewers). The Committee reviewed evidence from review reports, micro-simulation modelling using Alberta breast cancer screening data, and expert opinion. Decisions were made by weighing the benefits and harms in conjunction with the strength of the evidence using a modified Delphi process to reach consensus.

The priority topics for the 2022 update included:

New recommendations:

For persons with average risk, the biennial screening recommendation was lowered to begin at age 45 based on new evidence that mortality is reduced when screening prior to age 50. The participation rate for ages 45–49 was already 24% (vs. ages 50–74 which is 65%). In 2018, 246 breast cancers were detected in Albertans aged 45–49 (vs. 287 aged 50–54). New recommendations state that:

The updated guidance does not recommend MRI, ultrasound, tomosynthesis, thermography, or breast self-examination for routine screening. Specifically:

These changes are projected to impact the following:

Since the publication of the revised guideline, the total number of initial screens for persons in the 40-44 and 45-49 year age groups has increased, although the updated program is continuing to be fully implemented.

2.1.4 Roundtable Discussion Summary

This section presents a summary of key discussion items raised by participants and additional information provided by panelists during the roundtable session that followed each of the presentations summarized above.

Data and research on breast cancer screening:

Harms:

False positive:

Overdiagnosis:

OncoSim modelling:

Considerations for USPSTF recommendations as a reference:

Considerations for the Alberta Clinical Practice Guidelines as a model:

Tomosynthesis vs. mammography as screening modalities:

2.2 Stakeholder Perspectives – Gaining an Understanding

This panel showcased the experiences and perspectives of a range of stakeholders on breast cancer.

2.2.1 People with Lived Experience

Presented by Ms. Michelle Audoin (Uncovered: A Breast Recognition Project)

The panelist presented her lived breast cancer experience as a Black woman.

Key highlights of the presentation include:

Ms. Audoin talked about her first benign breast tumour removed from her right breast at age 14, and the fact that the scar was a source of shame and a constant reminder. She also spoke about how she was not given any information about breast health from her doctors at the time and had to learn how to perform self breast examination on her own. She was not advised of her high breast density until many years later when she received a breast cancer diagnosis.

As a young Black girl navigating the healthcare system, she did not feel represented in the images and stories about breast cancer and risk. She also had needs and concerns that were not addressed. She is currently living with stage four breast cancer.

Uncovered – A breast recognition project:

One of Ms. Audoin’s concerns was the need to see images of Black women and specifically breast reconstruction on women of colour, including information on how best to manage mastectomy scars. The fact that this information was non-existent led her to create Uncovered. It is the first of its kind of resource that has been created in collaboration with Rethink Breast Cancer. It was brought to life after years of Ms. Audoin journaling on her frustrations about not feeling seen and heard – and the lack of lack of culturally relevant and diverse images of breast cancer – within the healthcare system.

Uncovered has filled this gap and created a safe space for Black, Indigenous women and all people of colour to share their breast cancer stories, their experiences with the healthcare system, and, most importantly, providing access to diverse images of scars and breast reconstruction (available online for free). It is also a call to action in the form of a wish list for healthcare providers and community agencies to end disparities with easily accessible and actionable items.

Key takeaways:

Barriers and gaps in screening care:

Presented by Ms. Vicky auf der Mauer (Indigenous Primary Health Care Council and Aboriginal Legal Giiwedin Anang Council)

The panelist presented her lived breast cancer experience as an Indigenous woman.

Key highlights of the presentation include:

All of the concerns and frustrations related to disparities and lack of representation in the healthcare system for people of colour apply to Indigenous communities as well. Ms. auf der Mauer was featured in Uncovered, which was a transformational experience for her. It was the first time she had witnessed Indigenous representation for breast cancer.

In October 2019, Ms. auf der Mauer was diagnosed with breast cancer. As an Indigenous woman, she had no intention of utilizing Western medicine to treat the disease due to the perspective of it being an unwell, imbalanced, and sick system. She captured her experience by video and shared it in real-time.

When receiving her diagnosis, she felt pressured to schedule surgery right away. Her perception changed once she was matched with an Indigenous navigator – an Indigenous person who had lived experience of having the same diagnosis. Speaking with her, Ms. auf der Mauer became more receptive to the Western system although she still desired taking traditional medicines.

In 2021, Ms. auf der Mauer had two surgeries and completed radiation treatments as prescribed. Her decision-making process, supported by an Indigenous navigator, allowed her to come to peace with her decision to go ahead with treatment through the Western healthcare system. She feels that she found her voice during this process.

2.2.2 Canadian Breast Cancer Screening Network

Presented by Mr. Gregory Doyle (Canadian Breast Cancer Screening Network)

The panelist, who is Chair of the Canadian Breast Cancer Screening Network, titled his presentation "Noise, Evolution, and the Beauty of Hindsight," which showcased perspectives from the CBCSN.

Key highlights of the presentation include:

Hosted by the Canadian Partnership Against Cancer (CPAC), the Canadian Breast Cancer Screening Network is a community of practice with pan-Canadian membership (provincial/territorial breast cancer screening programs, PHAC, CPHA, and professional associations) that works together to ensure high quality, equitable, and culturally safe breast cancer screening in Canada. Members of the Network recognize the variation of breast cancer screening programs across different provinces and territories.

More specifically, current challenges that are being discussed by the Network include:

The CBCSN adheres to the World Health Organization (WHO) Principles of Population Screening as criteria for the assessment of evidence on benefits, risks, and costs of cancer screening. The following two principles are to be highlighted for breast cancer screening guidelines:

The evolution of breast cancer screening guidelines and programs:

Over the past 40 years, the CTFPHC’s guidelines have evolved from recommending annual mammography and clinical breast exam (CBE) for women aged 50–59 and not screening women aged 40–49 (with no recommendation for self breast examination [SBE]), then expanding the screening age to 50–69 and eventually to biennial screening from age 50–74 and informing women from the age of 40 about the benefits and risk of screening and recommending against CBE and SBE.

Breast cancer screening programs implemented in the late 1980s and 1990s have evolved with the changing guidelines with variation across the country in the age to start screening. Today, CBE is not offered as a screening modality and the teaching of SBE is no longer offered by health human resources. It was noted that it can be very challenging to implement shared decision-making (SDM) due to lack of access to primary care providers in 2023.

Updating the current breast cancer screening guidelines:

Key issues around the update of the breast cancer screening guidelines were presented, including the reliance on older RCTs, perceived bias toward harms, screening program data not being accepted as evidence, and legitimacy of the Canadian National Breast Screening Studies (CNBSS).

For the guideline update, it is recommended that the evidence base be expanded, screening program evidence be recognized, a diversity of voices be included, and that recent evidence be considered, such as improvements in breast imaging, technology, and breast cancer screening program delivery, and the use of up-to-date models.

In 2001, the CTPHC recommended that “Upon reaching the age of 40, Canadian women should be informed of the potential benefits and risks of screening mammography and assisted in deciding at what age they wish to initiate the manoeuvre.” Hindsight indicates that this may have been an appropriate way forward.

2.2.3 Family Physicians

Presented by Dr. Aisha Lofters (Women's College Research Institute)

The panelist delivered a presentation titled "Primary Care Perspectives," sharing her viewpoint as a primary care professional, which included a focus on health equity.

Key highlights of the presentation include:

Although there are breast cancer screening guidelines, there are still many questions that come up for physicians that can lead to inequitable care for patients, especially marginalized or underserved women or women facing socio-economic challenges. Hypothetical case studies were used to discuss equitable and clinically appropriate access to breast cancer screening.

Important considerations include:

Challenges in primary care:

2.2.4 Imaging Professionals

Presented by Dr. Jean Seely (Breast Imaging Section, The Ottawa Hospital)

The panelist, an imaging professional, shared her perspective during a presentation titled "Clinical Perspectives on Breast Cancer Screening Guidelines and/or Practice in Canada Today."

Key highlights of the presentation include:

Detection of breast cancer and outcome:

The proportion of breast cancers diagnosed by screening – not by symptomatic presentation (e.g., palpable lump, axillary mass, suspicious nipple discharge) – has decreased since 2016. A retrospective study at a tertiary-referral centre in 2016 found that screen detection vs. symptomatic detection in women 40 years and older had significantly lower odds of having advanced breast cancer and significantly lower odds of death at 4-year follow-up. Also, symptomatic cancers had 6.5 times higher odds of having advanced cancer compared to a lower stage.

Screening and survival:

In Canada, breast cancer represented 14% of all cancer deaths in women in 2022. Earlier diagnosis of breast cancer (and earlier stage) can lead to improved survival, decreased morbidity, and lowered cost of treatment. The stage at which a breast cancer is diagnosed correlates directly with survival:

Incidence and race:

The age of peak incidence of breast cancer varies by race and ethnicity. When compared with Black, Indigenous, Chinese, South Asian and Filipina women, only White women have a peak incidence after the 50–59 age group. This means that waiting to start screening at age 50 could impact these women differently.

Canadian National Breast Screening Studies:

The 2018 CTFPHC’s recommendations on screening for breast cancer in women aged 40–74 years who are not at increased risk were based on evidence coming from RCTs and data from women who were invited to screen only. These guidelines were informed by the Canadian National Breast Screening Studies (CNBSS) (I and II) studies that, apart from being 60 years old, are flawed by inclusion of people with symptoms of cancer, poor quality mammography, and high proportion of advanced cancer in the screening arm.

Organized screening programs on breast cancer stage at diagnosis for women aged 40–49 and 50–59:

In part because of the influence of the CNBSS in Canada, many provinces do not include women in their 40s in screening programs and only start at age 50. In a large study (2022) of 55,000 women with a breast cancer diagnosis in Canada, the distribution of breast cancer stage at diagnosis was significantly different between women in their 50s- and 40s not targeted by screening programs. Except for stage IV, women in their 40s had breast cancer diagnosed at significantly later stages than those in their 50s. Significantly higher proportions of stage I breast cancer were found in the screening jurisdictions, compared with those that did not include the women in their 40s. Those who did not include them had proportionately more breast cancer diagnoses at more advanced stages: Stage II (43.7% vs. 40.7%), Stage III (18.3% vs. 15.6%) and Stage IV (4.6% vs. 3.9%). There was also a significantly lower proportion of stage I breast cancer in women in their 50s (44.5% vs. 46.8%) and significantly higher proportions of Stage II (37.2% vs. 36.0%) and Stage III (13.6% vs. 12.3%).

Breast cancer screening on net survival in women aged 40–49:

A study (2022) looking at 10-year net survival in over 50,000 breast cancer cases from 2002 to 2007 from differing provincial and territorial screening policies found that:

Breast cancer was responsible for 90.7% of deaths in diagnosed women aged 40–49. The impact on mortality decreased with age (i.e., 80.9% for 50–59; 61.5% for 60–69; 48.3% 70–74). In older women, the concept of overdiagnosis (i.e., the detection and treatment of breast cancer that would not cause death) is most likely a factor with other competing causes of death.

The true cost of breast cancer treatment:

A Canadian study (2023) aimed to determine the true cost of breast cancer treatment using Activity-Based Costing (ABC) to determine a per-case cost by stage and molecular subtype. Expert input from diagnostic imaging, pathology, surgery, radiation oncology, medical oncology, pharmacy, cancer centre administration and modelling were used. The study also proportionally integrated the range of multidisciplinary evidence-based patient and provider treatment options (i.e., lumpectomy vs. mastectomy) to yield a single case cost for the total duration of treatment per case. The study concluded that the 26,175 breast cancer cases in 2017 cost $1.8 billion in total to treat (not including the cost of treating recurrent disease). For treatment by stage, it was found that costs increase exponentially by stage. Specifically:

Current wait times for follow-up/treatment at The Ottawa Hospital:

Presentation conclusions:

2.2.5 Roundtable Discussion Summary

This section presents a summary of key discussion items raised by participants and additional information provided by panelists during the roundtable session that followed the presentation by the panelists.

Accessibility:

Primary care crisis:

Remoteness:

Age:

All-cause mortality as a study endpoint:

Demographic / Race-based data gaps:

Higher mortality in Black women

Risk-based screening:

Breast density:

Cultural safety:

CNBSS data, and current guidelines:

Variation in screening practices:

2.3 Research and Innovation for Advancing Screening Practices – Current Challenges

This panel discussed current challenges related to breast cancer screening practices.

2.3.1 Shared Decision-Making

Presented by Dr. France Légaré (Department of Family Medicine and Emergency Medicine, Université Laval)

The panelist delivered a presentation on shared decision-making (SDM), titled "Shared Decision-Making in the Context of Population-Based Screening Programs."

Key highlights of the presentation include:

What is shared decision-making and what it is not?

Shared Decision-Making (SDM) is a process in which clinicians and patients work together in making decisions about the patient’s health care. It relies on two major pillars – the evidence and what matters most to the patient – and can be fostered by patient decision aids (e.g., The Ottawa Personal Decision Guide). Such decision aids can help identify the decision to be made, discuss the options available, explore preferred roles, and assess as well as address decision-making needs.

SDM is a tool. The tool is not meant to be used with a consumer approach (i.e., using the tool like a machine that will spit out an answer). Research indicates that patients still want to be supported in reaching a decision. A decision-making tool is not meant to replace the clinician in the decision-making process. Such a tool also poses the risk of wrongly being used and should never be used to replace an entire decision-making process (i.e., it is meant to help the process).

Why it is relevant to making choices in population-based screening programs?

To make decisions, we rely on ethics. From a teleological perspective, we rely on concepts such as consequentialism, values, and virtue. For example, see the Quintuple Aim.

From a deontological perspective, we rely on concepts such as duty, right, and proceduralism. As an example, in the ‘Rights and Entitlements in Relation to Health Care – Federal Initiatives’, the Health Charter for Canadians outlines a substantial list of individual rights for users of the public health care system, including the right to be:

The Cochrane Review of Patient Decision Aids Shared Decision-Making Tools and International Patient Decision Aids Standards 2023 update reported:

The pitfalls of SDM for breast cancer screening include lack of clinician-patient relationship and choice behaviour as an outcome (e.g., SDM may not increase screening uptake and could possibly decrease uptake).

The levers of SDM for breast cancer screening include partnerships and engagement of all stakeholders.

2.3.2 Risk-based Approach to Screening

Presented by Dr. Jacques Simard (Research and Innovation, Faculty of Medicine, Université Laval) & Dr. Anna Chiarelli (Ontario Health)

The panelists presentation was entitled “Implementation of risk-stratified breast cancer screening: Opportunities and Challenges.”

Key highlights of the presentation include:

Current challenges in breast cancer screening practices include:

Emerging evidence suggests that personalized breast cancer risk assessment at a population level could guide screening recommendations.

Development of a framework to support implementation of a personalized risk-based approach to breast cancer screening has included:

This study found that when screening based on multifactorial risk stratification level instead of age, family history, or Breast Imaging-Reporting and Data System (BIRADS) density alone, the higher-than-average and high-risk groups were found to be under screened (and average risk group was over screened based on family history and breast density only).

Drivers and challenges:

Implementing risk-based screening approach would allow for:

Although having much potential in improving screening, the implementation of a risk-stratified breast cancer screening approach is also challenged by:

Future directions:

To move forward with risk-based breast cancer screening in Canada, we need to:

  1. Develop recruitment and data collection processes that minimize disparities in access to breast cancer risk assessment at the population level
  2. Develop a multifactorial breast cancer risk prediction tool that is validated in different populations and user-friendly for health care providers and participants
  3. Develop a risk-based screening implementation framework within Canada’s socio-legal environment and healthcare organization structures

2.3.3 Issues Related to Access, Outreach, and Equity

Presented by Dr. Juliet Daniel (Research and External Relations, Faculty of Science, McMaster University)

The panelist’s presentation was entitled “Research and Innovation for Advancing Breast Cancer Screening Practices: Current Challenges in People of African Ancestry.”

Key highlights of the presentation include:

Breast cancer is clinically classified into subtypes based on expression of receptors: estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER-2). Tamoxifen is the standard treatment for ER/PR positive cancers while Herceptin is the standard treatment for HER-2 positive cancer. For triple negative (i.e., cancers that do not express any of the mentioned receptors), there is no targeted treatment; therefore, it has a poor prognosis.

Triple negative breast cancer and disparities in outcomes:

There is a higher incidence of Triple Negative Breast Cancer (TNBC) in young Black and Hispanic women compared to White women. While socio-economic status can explain poor health and disease outcomes, it cannot account for the incidence rate of TNBC. In addition, racism trauma (including slavery, community violence, racial profiling, mass incarceration, and abuse) is now being considered as a social determinant of health.

Demographic health data:

Breast cancer is an emerging health crisis in Africa with 5-year survival rate below 50% (compared to 90% in USA). The estimated TNBC prevalence is 20% in non-Hispanic Black Americans, 14–17% in Caribbeans, and 15–80% in Africans.

In Canada, there is a lack of demographic health data, forcing most researchers to use data from the U.S. (with unknown consequences). Today, most Canadian hospitals and institutions have begun collecting demographic data, but this data is not yet available.

A Canadian study (2016) looking at screening rates by ancestry found that screening rates were lowest for those women with no care, with rates ranging from 5.3% for South Asian women to 21.5% for Caribbean and Latin American women. Among those who had physicians, rates were highest among those enrolled in Family Health Teams (FHTs) (64.6%), and lowest for those not in a group. For all groups, screening rates were higher than 60% for those enrolled in FHTs and Family Health Organization (FHO) / Family Health Networks (FHNs), except for South Asian women and Eastern European and Central Asian women. Although having internationally trained physicians, there were significantly lower chances of screening compared to having domestically trained physicians for the overall cohort – the differences were only significant for women from Caribbean and Latin American and East Asia and Pacific. Having a family physician who was from the same region as the woman significantly increased the chances of screening for South Asians, Eastern Europe and Central Asian, and Middle East and North Africa.

Another study (2018) looking at age standardized incidence rates and mortality by country found that Caribbean countries (Barbados and Bahamas), had much higher mortality rates, along with very high incidence rates, compared to the world population.

Kaiso – A multi-faceted transcription factor:

Kaiso is a transcription factor that regulates many biological processes such as cell proliferation, apoptosis (cell death), cell motility, and inflammation. It plays a role in multiple cancers. High Kaiso expression correlates with poor survival in breast cancer.

Recommendations:

2.3.4 Roundtable Discussion Summary

This section presents a summary of key discussion items raised by participants and additional information provided by panelists during the roundtable session that followed the presentation by the panelists.

Risk-based screening:

Shared decision-making and decision aids:

Weighing benefits vs. harms for guidelines:

2.4 Research and Innovation for Advancing Screening Practices – Looking to the Future

2.4.1 Circulating Biomarkers

Presented by Dr. Scott Bratman (Princess Margaret Cancer Centre Research Institute)

The panelist’s presentation was entitled “Research and Innovation for Advancing Screening Practices – Circulating Biomarkers.”

Key highlights of the presentation include:

Overview of liquid biopsy cancer diagnostics:

A liquid biopsy refers to a blood sample taken to detect cancer-derived cells and DNA in the bloodstream. Circulating tumour DNA (ctDNA) can be used as a biomarker for cancer in the blood. It outperforms other circulating biomarkers for breast cancer:

Cancer-derived DNA markers in ctDNA can be challenging to find, yet can be identified using:

ctDNA could become an integral component of personalized medicine across the entire cancer care continuum.

  1. Cancer detection, screening, or earlier diagnosis:
    No tests are approved or funded. Although blood tests could enable simultaneous multi-cancer detection, studies are ongoing for both screened and unscreened cancers.
  2. Molecular profiling or prognostication:
    There are tests approved by the U.S. Food and Drug Administration for targeted therapy selection. Advanced stage cancers have higher levels of ctDNA, and studies show that we can avoid tissue biopsy.
  3. Detection of residual disease, monitoring response, and monitoring clonal evolution:
    No tests are approved or funded. There is emerging evidence supporting its use in colon, breast, and other cancers. There are many ongoing clinical trials on the matter.

Liquid biopsy for detecting early recurrence:

Current curative-intent treatments involve complex decisions for escalation or de-escalation of therapy. For example, after surgical and/or radiation treatment, one is faced with the decision to observe or continue with adjuvant therapy. Molecular Residual Disease (MRD)Footnote 3 detection could guide curative-intent treatment decisions. For instance, an MRD positive test would confirm the need for adjuvant therapy while an MRD negative test would confirm that observation is sufficient. Furthermore, ctDNA reflects MRD status and is strongly prognostic in colon, lung, head and neck, and breast cancers.

Liquid biopsy approaches to cancer screening:

When looking at current recommended cancer screening programs, their proven advantage is in the reduction in mortality for cervical, breast, colon, and lung cancers. Yet, current screening practices still have challenges and limitations, such as:

Blood-based liquid biopsy cancer screening tests could possibly address the following challenges:

Proof-of-concept for cancer screening of virally-driven cancers using liquid biopsy include Human papillomavirus (HPV) associated with oropharynx, cervix, and anogenital cancers, and Epstein–Barr virus (EBV) associated with nasopharynx, gastric, and lymphoma cancers. For example, a study (2017) using plasma EBV DNA to screen for nasopharyngeal cancer identified predominantly early-stage cancers with favourable survival. A RCT would be needed to prove reduction in late-stage cancer incidence as well as cancer-specific mortality.

The promise of liquid biopsy is the ability to leverage the bloodstream as a source of cancer signals from multiple tissues. Multi-cancer detection with blood-based tests has its benefits, including its scalability for population screening, possibility to simplify clinical care and encompassing rare cancers. As for single cancer detection, the benefits include faster development, more direct regulatory pathway, and already existing proven screening paradigms. In both cases, limitations include costs to develop tests and to do individual tests, cumulative false positives, complex development, regulatory pathways, and possible diagnostic odyssey.

Blood-based cancer early detection tests require performance attributes (i.e., high sensitivity for early-stage cancers, high specificity to minimize workups) and accessibility attributes (i.e., globally deployable via a single blood draw, efficient, cost-effective, and comprehensive). It also requires the following features: high accuracy for identifying cancer type and tissue of origin and the ability to monitor disease and reveal biology.

Epigenetic changes such as DNA methylation show promise for blood-based multi-cancer detection. ctDNA methylation assays can detect multiple cancers, but based on current published data, the sensitivity for breast cancer is too low for primary screening (i.e., 30.5% sensitivity). Breast cancer detection sensitivity seems to be stage and subtype dependent. The detection of methylated ctDNA is useful for prognosis in other cancers, yet not for breast cancer.

Presentation conclusions:

2.4.2 Artificial Intelligence

Presented by Dr. Nehmat Houssami (Breast Cancer Clinical and Population Health Research Group, Daffodil Centre [Australia])

The panelist’s presentation was entitled “Research and Innovation for Advancing Screening Practices: Looking to the Future – Artificial Intelligence.”

Key highlights of the presentation include:

The focus of this presentation was centred around the use of Artificial Intelligence (AI) for breast cancer population screening to improve workflow and potentially screening participants’ outcomes. AI could be applied for cancer detection (i.e., current risk) or to evaluate future risk. AI for breast cancer screening is currently defined as an ‘early use’ case where a collection of interrelated technologies is used to solve problems that would otherwise require human cognition. AI is a branch of computer science concerned with building machines and software capable of performing tasks that typically require human minds (e.g., perceiving, reasoning, learning, interacting).

Current evidence:

A scoping review (2019) on AI for early breast cancer detection revealed that most publications on this topic are mostly small retrospective studies with highly selected image datasets (i.e., high cancer %). Experts agree that such methodological concerns and evidence gaps limit the translation of AI into clinical breast cancer screening settings. The methodological limitations highlighted include:

A systematic review (2022) on the validation of AI algorithms for automated screening mammography revealed a small potential for diagnostic accuracy improvements. Studies on this topic still suffer from risk of bias and applicability concerns, including inadequate ascertainment of outcomes. Experts agree that the quality of studies needs improvement.

A retrospective cohort study (2023) looked at 109,000 consecutive screening exams from November 2015 to December 2016 in women aged 50–74 using the BreastScreen AI software (complete 2-year follow-up and linkage with cancer registry to ascertain interval cancers). It was found that AI did not perform as well as radiologists at prospective (pre-defined) threshold:

This study also revealed that the proportion of screen-detected cancers that were AI-positive was 77% and the proportion of interval cancers detected by the AI was 37%. A simulated double-read (i.e., radiologist + AI reading) was also performed and it was found that the retrospective design could not quantify the potential cancer detection rates due to limitations in analytic arbitration. These results confirm the need for prospective trials.

A clinical safety analysis study (2023) compared Mammography Screening with AI (MASAI) compared AI-supported screen reading vs. standard double reading. The trial recruited in 2021-2022 from four screening sites in the Swedish Screening Program using prespecified safety analysis (80,000 screens) for detection metrics where the primary endpoint was interval cancer rate (100,000 screened participants with at least a 2-year follow-up). This AI intervention resulted in higher recall rate and cancers found (as well as a higher cancer detection rate) while having 44% less screen-readings. The deep learning-based CAD system (Transpara v.1.7) was used to:

A prospective, population-based, paired-reader, non-inferiority study (2023) recruited in 2021–2022 during routine mammography screening in Sweden. The study was based on 55,581 screens using Insight MMG AI system (v1.1.6; Lunit, South Korea) and design to have double reading plus AI reading followed by consensus meeting for discordance. It was found that double reading by one radiologist plus AI was non-inferior for cancer detection compared with double reading by two radiologists. Also, the study revealed a higher abnormal interpretation rate for AI resolved at consensus meetings.

AI for breast cancer risk screening:

AI for breast cancer risk prediction is an emerging area of research in which the extent and quality of evidence is not yet well developed. The various risk factors that drive an individual’s risk of developing breast cancer should be considered in risk estimation and include personal and lifestyle characteristics, reproductive and hormonal factors, familial and generic factors, and mammogram-derived information.

Is AI for breast cancer screening acceptable to the population served?

A study on Australian women’s judgments about using AI to read mammograms was conducted by running eight online dialogue groups of women aged 50–74. The two main questions discussed were:

Feedback was mainly positive; however, two issues were raised:

  1. Performance and quality assurance (i.e., AI should only be introduced when this makes performance of screening better than status quo).
  2. Experts remaining central actors (i.e., radiologists should remain responsible – to support explanation of outcomes, accountability, quality assurance – since radiology expertise is seen as a valuable resource).

Presentation conclusions:

2.4.3 Roundtable Discussion Summary

This section presents a summary of key discussion items raised by participants and additional information provided by panelists during the roundtable session that followed the presentation by the panelists.

Blood tests for screening:

Artificial Intelligence (AI) in breast cancer screening:

3.0 Roundtable Discussions

3.1 General Discussion Highlights

Education and awareness:

Stakeholder Final Reflections

At the end of the event, there was a final roundtable discussion on breast cancer screening that was guided by the following questions:

Key highlights include:

Appendices

Appendix A – Event Program

Day 1 – Tuesday 26 September 2023

11:00–11:05

Welcome – Julie Desmarais (Facilitator)

11:05–11:10

Algonquin Knowledge Keeper Opening – Monique Manatch (Knowledge Keeper)

11:15–11:25

Opening Remarks – Nancy Hamzawi (Executive Vice-President, Public Health Agency of Canada)

11:25–11:35

Overview of event and review of objectives – Julie Desmarais (Facilitator)

11:35–12:35

Setting the Stage – Breast Cancer Screening Guidelines in Canada and Abroad

This panel will showcase the experiences of groups developing breast cancer screening guidelines in Canada and abroad including presentations from the:

12:35–13:30

Roundtable Discussion

13:30–14:00

Break

14:00–15:00

Stakeholder Perspectives – Gaining an Understanding

This panel will showcase the experiences and perspectives of a range of stakeholders on breast cancer screening including presentations from:

15:00–15:25

Roundtable Discussion

15:25–15:30

Closing Remarks for Day 1 – The Honourable Ya'ara Saks, Minister of Mental Health and Addictions and Associate Minister of Health

Note: All times are Eastern Daylight Time.

Day 2 – Wednesday 27 September 2023

11:00–11:02

Welcome – Julie Desmarais (Facilitator)

11:02–11:10

Opening Remarks – Nancy Hamzawi (Executive Vice-President, Public Health Agency of Canada)

11:10–12:15

Research and Innovation for Advancing Screening Practices – Current Challenges

This panel will discuss current challenges related to breast cancer screening practices, including presentations on:

12:15–13:00

Roundtable Discussion

13:00–13:30

Break

13:30–14:30

Research and Innovation for Advancing Screening Practices – Looking to the Future

This panel will discuss future research foci to advance breast cancer screening practices, including presentations on:

14:30–15:15

Roundtable Discussion

15:15–15:25

Closing Remarks – Heather Jeffrey (President, Public Health Agency of Canada)

15:25–15:30

Algonquin Knowledge Keeper Closing – Monique Manatch

Note: All times are Eastern Daylight Time.

Appendix B – Presenters’ Biographies

Canadian Task Force on Preventive Health Care

Dr. Guylène Thériault is the co-chair of the Canadian Task Force on Preventive Health Care and, in addition to her clinical duties, Dr. Thériault is a co-lead for family practice for Choosing Wisely Canada and has been teaching evidence-based medicine and shared decision-making to students, residents and physicians for several years. She has different academic duties at the McGill Campus in Outaouais and is the founder of the centre for the advancement of evidence-based health care, a website that proposes tools to help incorporate sound care and prevention in clinical practice.

Dr. Ahmed Abou-Setta is the other co-chair of the Canadian Task Force on Preventive Health Care and an Assistant Professor in the Department of Community Health Sciences at the University of Manitoba, the Director of Knowledge Synthesis at the George & Fay Yee Centre for Healthcare Innovation also at the University of Manitoba, the CIHR-funded Manitoba Strategy for Patient Oriented Research (SPOR) SUPPORT Unit, and a Principal Investigator on the CIHR-funded SPOR Evidence Alliance. He leads and supports patient-oriented research including clinical practice guidelines, systematic reviews, and overviews of reviews.

U.S. Preventive Services Task Force

Dr. Wanda Nicholson was appointed as Vice-Chair of the U.S. Preventive Services Task Force in March 2022. She is an obstetrician-gynecologist by training and currently Professor of Prevention and Community Health at the George Washington Milken Institute of Public Health. She is a perinatal and women's health researcher with a focus on developing behavioural interventions for diabetes and hypertensive disorders of pregnancy.

Alberta Health Services

Mr. James Newsome is the Lead of the Program Innovation & Integration team with Alberta Health Services’ Screening Programs. He has worked in Screening Programs for the past six years and in health care for 13 years, and holds degrees in science, clinical research, and business administration. He coordinated and helped develop the new Alberta Breast Cancer Screening Clinical Practice Guideline.

Patients

Ms. Michelle Audoin is the creator of Uncovered: A Breast Recognition Project and lives with stage 4 breast cancer. She collaborates with and advocates for the unmet needs of under-supported communities in the cancer care space with a focus on health equity and the patient voice.

Ms. Vicky auf der Mauer is a proud Inuk woman from the Qikiqtaaluk Region of Nunavut, known as Baffin Island, now living in Dish with One Spoon Territory, otherwise known as Toronto. She is a Storyteller and Beneficiary of the Nunavut Land Claim Agreement. She sits as a Knowledge Keeper for the Indigenous Primary Health Care Council (IPHCC) and Aboriginal Legal Giiwedin Anang Council, an Indigenous approach to supporting custody disputes by child welfare agencies. After receiving a serious health diagnosis in 2019 and unclear on what direction she wanted to go, she first took it to her Indigenous community, eventually walking through the Western medical system to receive treatment. She shares her journey and all the lessons that went along with it.

Canadian Breast Cancer Screening Network

Mr. Gregory Doyle is the Division Manager for Breast Cancer Screening and Cervical Cancer Screening Initiative programs in Newfoundland and Labrador and the Chair of the CBCSN.

Women's College Research Institute

Dr. Aisha Lofters is a scientist at the Women's College Research Institute (WCRI), adjunct senior scientist at the Institute for Clinical Evaluative Sciences (IC/ES), and an Associate Professor in the Department of Family and Community Medicine at the University of Toronto. She previously held a New Investigator Award from the Canadian Institutes of Health Research and is the Medical Director and Chair in Implementation Science at the Peter Gilgan Centre for Women’s Cancers at Women’s College Hospital in partnership with the Canadian Cancer Society. Her research program focuses on improving quality of care in cancer screening and prevention, particularly for populations that experience marginalization, through a variety of methods including community-partnered approaches.

University of Ottawa – Breast Imaging Section

Dr. Jean Seely is a full Professor in the Department of Radiology at the University of Ottawa, Head of the Breast Imaging Section at the Ottawa Hospital, and Regional Breast Imaging Lead for the Ontario Breast Screening Program in the Champlain region. She is the President of the Canadian Society of Breast Imaging and a Fellow of the Society of Breast Imaging and the Canadian Association of Radiologists. Her research interests include Breast MRI, breast cancer screening, quality in breast imaging, and patient experience.

Université Laval – Department of Family Medicine and Emergency Medicine

Dr. France Légaré is a family doctor in Québec City, with a master’s degree in community health and a PhD in Population Health from the University of Ottawa. She is a full Professor in the Department of Family Medicine and Emergency Medicine at Université Laval and holds the title of Canada Research Chair in Shared Decision-Making and Knowledge Mobilization since 2006.

Université Laval – Research and Innovation at the Faculty of Medicine / Department of Molecular Medicine / Université Laval Research Centre

Dr. Jacques Simard is currently Vice-Dean of Research and Innovation at the Faculty of Medicine at Université Laval, Professor for the Department of Molecular Medicine, and a Scientist at the Centre Hospitalier Universitaire (CHU) de Québec – Université Laval Research Centre. He was the chairholder of Canada Research Chair in Oncogenetics (2001-2022). Since 2001, he is heading one of the largest interdisciplinary and international research teams on genetic susceptibility to breast cancer guided by open science principles.

Ontario Health

Dr. Anna Chiarelli is a senior scientist at Ontario Health (formerly Cancer Care Ontario), the provincial scientific lead of the Ontario Breast Screening Program and professor in epidemiology in the Dalla Lana School of Public Health at the University of Toronto. Professor Chiarelli currently co-leads a large-scale applied research project called “Personalized Risk Assessment for Prevention and Early Detection of Breast Cancer: Integration and Implementation. This multi-institutional international project seeks to further the implementation of risk-stratified breast screening guidelines in a cost-effective manner.”

McMaster University – Faculty of Science

Dr. Juliet Daniel is a Cancer Biologist and the Associate Dean of Research and External Relations in the Faculty of Science at McMaster University. Professor Daniel’s research is focused on elucidating the role of the transcription factor Kaiso in cancer and vertebrate development. Her team is also currently elucidating the molecular/genetic causes of the disparities in incidence and poor outcomes of Triple Negative Breast Cancer in Black women. In recognition of her research and community service, Professor Daniel has received several awards including the inaugural Canadian Cancer Society Inclusive Excellence Award.

Princess Margaret Cancer Centre / University Health Network / University of Toronto

Dr. Scott Bratman is the Staff Radiation Oncologist at Princess Margaret Cancer Centre / University Health Network and Associate Professor at University of Toronto. Dr. Bratman is known for his contributions to novel liquid biopsy methods with immense scientific and clinical impact. His ground-breaking research has produced fundamental discoveries in cell-free DNA biology, technologies, and applications for precision medicine and response monitoring in oncology.

Daffodil Centre – Breast Cancer Clinical and Population Health Research Group

Dr. Nehmat Houssami is a clinician researcher and a Public Health physician, and Professor of Public Health. She leads the Breast Cancer Clinical and Population Health Research group at the Daffodil Centre. She has worked in breast screening services for approximately 30 years and is a clinician at the Royal Hospital for Women in Sydney. Professor Houssami’s expertise is in evaluating new technologies including screening trials; she is the National Breast Cancer Foundation Chair in Breast Cancer Prevention, and a National Health & Medical Research Council Leader Fellow.

Appendix C – List of Acronyms

ACTT
Alberta Medical Association’s Accelerating Change Transformation Team
ABC
Activity-based costing
AI
Artificial intelligence
BCSC
Breast Cancer Surveillance Consortium
BIRADS
Breast Imaging-Reporting and Data System
CBCSN
Canadian Breast Cancer Screening Network
CBE
Clinical breast exam
CHU
Centre Hospitalier Universitaire
CIHR
Canadian Institutes of Health Research
CNBSS
Canadian National Breast Screening Studies
CPAC
Canadian Partnership Against Cancer
CPG
Clinical Practice Guideline
CPHA
Canadian Public Health Association
CTCs
Circulating tumour cells
ctDNA
Circulating tumour DNA
CTFPHC
Canadian Task Force on Preventive Health Care
DBT
Digital breast tomosynthesis
DCIS
Ductal carcinoma in situ
ER
Estrogen receptor
FHNs
Family Health Networks
FHO
Family Health Organization
FHTs
Family Health Teams
HER-2
Human epidermal growth factor receptor-2
IC/ES
Institute for Clinical Evaluative Sciences
IPHCC
Indigenous Primary Health Care Council
KEE
Knowledge Exchange Event
MASAI
Mammography Screening with AI
MRD
Molecular Residual Disease
MRI
Magnetic Resonance Imaging
OSF
Open Science Framework
PHAC
Public Health Agency of Canada
PR
Progesterone receptor
PRS
Polygenic Risk Score
RCTs
Randomized controlled trials
SBE
Self breast examination
SDM
Shared decision-making
SEER
Surveillance, Epidemiology, and End Results
SPOR
Strategy for Patient Oriented Research
TNBC
Triple Negative Breast Cancer
USPSTF
U.S. Preventive Services Task Force
WAA
Women of African ancestry
WCRI
Women's College Research Institute
WHO
World Health Organization

Appendix D – Glossary of Important Terms

All-cause mortality:
is defined as the death rate from all causes of death for a population.
Benefits (breast cancer screening related):
refers to the benefit of potentially finding breast cancer before symptoms appear. Earlier detection can lead to better outcomes.
Biomarkers:
are measurable substances in an organism whose presence is indicative of disease – in this case, breast cancer.
Circulating tumour DNA (ctDNA):
is single- or double-stranded DNA that contains mutations and that is released by tumour cells into the blood.
Cultural safety:
refers to an environment that is free of racism and discrimination where patients feel safe. It is based on respectful engagement that recognizes and strives to address power imbalances inherent in the healthcare system.
Dense breast:
is used to describe breast tissue that has relatively high amounts of glandular tissue and fibrous connective tissue (and relatively low amounts of fatty breast tissue).
Detection:
refers to identifying the presence of breast cancer using imaging or molecular methods.
DNA methylation:
is a biological process by which methyl groups are added to DNA molecules, which can change the activity of a DNA segment without changing its sequence.
Epigenetic changes:
refer to alterations in cellular function that are not due to a change in DNA sequence. They are reversible, yet heritable, and relate to environmental factors.
False positive:
is a test result that is incorrectly classified (as for the presence of breast cancer) requiring further testing to confirm the absence of disease (i.e., "call back”).
Harms (breast cancer screening related):
refers to negative outcomes of screening, such as causing anxiety and worry in an individual, false positive leading to more tests, and overtreatment/overdiagnosis.
Health equity:
refers to the state in which every individual has a fair and just opportunity to attain their highest level of health.
Interval cancer:
a cancer that is found during the time between regular mammogram screenings (for example, because a person feels a breast lump and diagnostic assessments determine it is breast cancer)
Liquid biopsy:
refers to a blood sample taken to detect cancer-derived cells and DNA in the bloodstream.
Overdiagnosis:
it is defined as the detection of a cancer that would not result in harm to the patient (i.e., that would not cause death to the patient, who might die of other causes). This includes a cancer that would not have become symptomatic and that was only found through screening. Overdiagnosis of precancerous lesions (e.g., DCIS) can be distinguished from overdiagnosis of cancers.
Overtreatment (resulting from overdiagnosis):
refers to treatment interventions that do not necessarily benefit the patient, or where the risk of harm from the intervention is likely to outweigh any benefit to the patient.
Risk factor:
can be defined as something that increases the risk or susceptibility to breast cancer. Such factors can be genetic or environmental.
Screening (breast cancer-related):
the evaluation or investigation using imaging technologies and/or molecular tests for identifying the presence of breast cancer in asymptomatic individuals.
Shared decision-making:
is a process in which physicians and patients work together to make medical decisions that consider potential benefits and harms, while considering the patient’s values and preferences. It is considered a key component of patient-centred health care.

Appendix E – Resources

Footnote 1

The CTFPHC publicly announced on November 15, 2023 that due to the complexity and volume of data to be assessed, it is now targeting a spring 2024 release date for updated recommendations (https://canadiantaskforce.ca/revised-timeline-for-breast-cancer-screening-update/­)

Return to footnote 1 referrer

Footnote 2

CPAC provided clarification to PHAC after the KEE that OncoSim has actually been updated for the variable of survival in 2023 and is in the process of updating treatment cost variables with a target of early 2024. OncoSim updates are made regularly (several times a year), with new assumptions added based on fresh data, features, and output tables. Recent updates to OncoSim bring incidence and survival estimates and projections in line with the most currently available data in the Canadian Cancer Registry (up to diagnosis year 2020).

Return to footnote 2 referrer

Footnote 3

MRD tests are now standard for leukemias and prostate cancer, while a vast majority of solid cancers lack a reliable MRD biomarker.

Return to footnote 3 referrer

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