Objective: To examine the characteristics of malignant tumours that develop in women undergoing surveillance for increased risk for breast cancer and to identify presentation patterns in order to determine the respective roles of mammography, clinical breast examination (CBE) and breast self-examination (BSE).
Setting: Breast Diagnostic Clinic and Familial Breast Cancer Clinic at Toronto-Sunnybrook Regional Cancer Centre.
Participants: A total of 1044 women evaluated for breast cancer risk from Oct. 1, 1990, to Dec. 31, 1996, of whom 381 were categorized as being at high risk, 204 as being at moderate risk, 401 as being at slightly increased risk and 58 as being at no appreciably increased risk.
Program components: Comprehensive review and discussion of risk factors, clinical assessment, surveillance recommendations that include mammography, CBE and BSE, genetics consultation (Familial Breast Cancer Clinic) and psychosocial support. Data are captured prospectively, updated at each visit and audited every 3 to 6 months.
Program outcomes: During the study period breast cancer was diagnosed in 24 patients, 12 in the high-risk group, 4 in the moderate-risk group and 8 in the group at slightly increased risk. The mean age at diagnosis was 47 (range 32 to 82) years. Ten cases of cancer were diagnosed during surveillance (incident cancer), 5 in women under age 50. The mean length of time from initial assessment to diagnosis was 28.6 (range 12 to 51) months. Of the 24 women, 17 reported a family history of breast cancer. The mean age at diagnosis in this cohort was 45.5 years, and the diagnosis was made under age 50 in 10 patients (59%). The mean earliest age at which breast cancer was diagnosed in a family member was 42.5 years.
Conclusions: These preliminary results suggest that surveillance of women at increased risk for breast cancer may be useful in detecting disease at an early stage. The regular performance of mammography, CBE and BSE appears necessary to achieve these results.