ARCHIVED - What should I know about breast cancer?


Breast cancer is the most common cancer in Canadian women. It can also be found in men but this is very rare. Almost all breast cancers start in the glandular tissue of the breast and are known as adenocarcinomas. Cancer cells may start within the ducts (ductal carcinoma) or lobules (lobular carcinoma). Ductal carcinoma is the most common type of breast cancer.

What causes breast cancer?

There is no single cause of breast cancer but some factors that increase the risk of developing the disease include:

  • Age: 80% of the cases of breast cancer occur in women over 50 years of age.
  • Family history of breast cancer, especially in a mother, sister or daughter diagnosed before menopause, or if a mutation on the BRCA1 or BRCA2 genes is present.
  • Previous breast disorders with biopsies showing abnormal cells.
  • No full term pregnancies or having a full term first pregnancy after age 30.
  • High breast tissue density.
  • In post menopausal women: obesity and physical inactivity.
  • Beginning to menstruate at an early age.
  • Later than average menopause.
  • Taking hormone replacement therapy (estrogen plus progestin) for more than 5 years.
  • The use of oral contraceptives, may be associated with a slight increase in breast cancer risk.
  • Alcohol use is associated with a modest increase in breast cancer risk.

Early detection and screening for breast cancer

Finding breast cancer early even when there are no symptoms is important. Early diagnosis of breast cancer when it is small and less likely to have spread to the other parts of the body results in effective and simpler treatment thus improving the quality of life and reducing a woman's chance of dying from the disease. Mammography is the most reliable method of detecting breast cancer. Speak to your doctor about breast cancer screening.

Additional resources

Prepared by the Canadian Cancer Society. This information appeared originally on the Canadian Health Network Web site.

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