Breast Cancer in Canadian Women

HEALTH ISSUE: Although lung cancer is the leading cause of cancer deaths for Canadian women, breast cancer is the most frequently diagnosed. About 5400 women are expected to die from this disease in 2003. In 1998, a woman's lifetime risk of breast cancer was about one in nine. KEY FINDINGS: A number of risk factors for breast cancer have been identified. These include advancing age, hormonal factors (eg. early menarche, late menopause and late age at first full-term pregnancy), familial risk, BRCA-1 and BRCA-2 gene mutations, diet and postmenopausal obesity. Several interventions have been introduced to assist women at high risk for breast cancer, including genetic counseling and testing for women who have strong family histories of breast cancer; selective estrogen receptor modifiers, such as tamoxifen, that has been shown to reduce breast cancer rates; prophylactic mastectomy and screening. DATA GAPS AND RECOMMENDATIONS: Guidelines are unclear in several areas, particularly in screening. Where clinical guidelines are available, health services research or ongoing monitoring (by provincial/territorial cancer agencies) is needed to assess compliance with the guidelines and to ensure equity of access within the provinces/territories. Key components of organized screening programs need to be established, in part to ensure that screening is carried out in high-quality, co-ordinated programs. There is also a need to develop ways to involve women fully in informed decision-making and to address several policy issues to prevent disparities in access to high-quality services. Patenting issues associated with genetic tests also need to be clarified.