Breast cancer statistics

Breast cancer is the most common cancer among Canadian women (excluding non-melanoma skin cancers). It is the second leading cause of death from cancer in Canadian women. Breast cancer can also occur in men, but it is not common.

To provide the most current cancer statistics, statistical methods are used to estimate the number of new cancer cases and deaths until actual data become available.

The rate of new cases of breast cancer in women in Canada rose between 1984 and 1991. The rate has fluctuated since then, with an overall small decrease.

The increase until the early 1990s occurred partly because mammography was used more often, which meant that more cases of breast cancer were found. The reasons for the later fluctuation are not clear but may include long-term changes in hormonal factors, like if a woman started having her menstrual periods when she was young, breastfeeding and oral contraceptive use.

The slight decrease in rate in 2002 coincided with a drop in the use of hormone replacement therapy among post-menopausal women when its role in breast cancer was publicized.

The breast cancer death rate peaked in 1986 and has been declining since. This reduction in death rates likely reflects the impact of screening and improvements in treatment for breast cancer.

It is estimated that about 1 in 8 Canadian women will develop breast cancer during their lifetime and 1 in 34 will die from it.

For more information about cancer statistics, go to Canadian Cancer Statistics.