Chapter 4: Cancer incidence in Canada: trends and projections (1983-2032) – All other cancers - HPCDP: Volume 35, Supplement 1, Spring 2015

Chapter 4: Projections by Cancer Site

24. All other cancers

In 2003–2007, the average annual number of all other cancers in Canada was 7005 for males and 6995 for females, representing 8.7%and 9.4%of all new male and female cancer cases, respectively (Tables 4.24.1 and 4.24.2).

During the same period, the ASIRs of these cancers increased with age from 6.2 per 100 000 in those aged 44 or younger to 466.4 in those aged 85 or older in males and from 6.3 to 345.4 in females in the same age groups. For those aged 54 or younger, the increase was less pronounced (Table 4.24.3 and 4.24.4). The ASIRs were virtually the same for males and females younger than age 55 but were higher in men than in women after this age. Overall, all other cancers occurred nearly 1.3 times as often in males as in females. Tables 4.24.1 and 4.24.2 show that more than 80% of all other cancer cases occurred in people aged 55 or older.

Figure 4.24.1 illustrates that overall incidence rates for this group increased modestly in males during the first 3 observation periods and then stabilized. For females, the overall rates increased steadily throughout the whole observation period. During 1998–2007, the ASIRs for all other cancers increased non-significantly in males by 0.1% per year and increased significantly by 0.6% in females (data not shown).

The inter-regional comparison indicated that, in the last 10 years of observation, male ASIRs increased in Ontario and Quebec, and decreased in other regions (Figure 4.24.1). For females, the ASIRs have increased gradually since the early 1990s in most regions. Figure 4.24.2 shows that the ASIRs increased consistently in females of all age groups since 1988–1992, and in males aged 65 or older.

For males, the incidence rates of all other cancers are projected to stabilize (at about 40 per 100 000) for Canada as a whole (Figure 4.24.1). At the regional level, the rates in Ontario are expected to continue to increase consistently, whereas the incidence in Quebec will tend to increase marginally in the next 5 years and thereafter decrease steadily. The rates in other regions will continue to decrease. For females, the overall rates are projected to increase until 2013–2017 and then level off. Similar trends will occur in British Columbia, the Prairies and Quebec. The rates in females will increase slightly in Ontario and the Atlantic region. Figure 4.24.2 shows that the ASIRs in Canada are estimated to increase and then level off in all age groups except in men aged 45 to 74, for whom the rates will decrease.

From 2003–2007 to 2028–2032, the ASIRs of all other cancers for Canada are projected to fall by 5% in males, from 40.7 to 38.7 per 100 000, and to rise by 7% in females, from 32.3 to 34.6 per 100 000 (Tables 4.24.3 and 4.24.4). The annual number of new cases in males is projected to increase by 91%, from 7005 to 13 390, and the number of new cases in females, by 92%, from 6995 to 13 405 (Tables 4.24.1 and 4.24.2).

Comments

“All other cancers” is a heterogeneous category. The distributions of the most common types of non-sex-specific cancers in this group were generally the same for males and females between 2003 and 2007. During this period, the most frequently diagnosed cancers were cancers of other digestive system (10% in males and 12% in females), soft tissue including heart (8% in males and 6% in females), and all other and unspecified primary sites (47% in both males and females). Mesothelioma accounted for a larger proportion of cancers in males (5%) compared with females (1%). The number of Canadian males diagnosed with mesothelioma rose from 153 cases in 1984 to 420 cases in 2007 (data not shown) because of exposure to asbestos in the 1950s, 1960s and 1970s.^{Endnote 311} The incidence rate also increased from 1.4 to 2.3 per 100 000.

Cancer of other female genital system organs accounted for 11% of this category in females. The remaining represented cancers of minor sites, in particular the digestive and respiratory systems, and the urinary organs. The vast diversity of this category makes it difficult to identify the reason for the projected trends.

The presence of numerous types of rare and complex cancers in this category makes it a challenge for either the cancer care system or researchers to deal with. One implication is that there may be value in research that examines multiple rare cancers that contribute to this group.