Effectiveness of breast cancer surveillance in BRCA1/2 gene mutation carriers and women with high familial risk

Abstract

Purpose: Women with a high breast cancer risk due to a familial predisposition may choose between preventive surgery and regular surveillance. The effectiveness of surveillance in high-risk women and especially BRCA1/2 mutation carriers is unknown. We present first results from a single large family cancer clinic.

Patients and methods: Women with breast cancer risk over 15% were examined by physical examination every 6 months and mammography every year. Detection rates and screening parameters were calculated for the total group and separately for different age and genetic risk groups.

Results: At least one examination was performed in 1,198 women: 449 moderate and 621 high-risk women and 128 BRCA1/2 mutation carriers. Within a median follow-up of 3 years, 35 breast cancers were detected (four ductal carcinoma-in-situ; 31 invasive tumors); the average detection rate was 9.7 per 1,000. Detection rates (95% confidence interval) for moderate and high-risk women and BRCA1/2 carriers were 3.3 (1.1 to 8.6), 8.4 (5.4 to 13.2), and 33 (17 to 63) per 1,000 person-years, respectively. The ratio of observed cases versus breast cancers expected in an average-risk population of comparable age was 2.7, 7.0 and 23.7 respectively. Overall, node negativity was 65%; 34% of primary tumors were less than 10 mm; sensitivity was 74%. Results with respect to tumor stage and sensitivity were less favorable in BRCA1/2 carriers and in women under the age of 40.

Conclusion: It is possible to identify young women at high risk for breast cancer. The number of cancers detected was significantly greater than expected in an age-matched average-risk population and related to the risk category. Overall, screening parameters were comparable to population screening data, with less favorable results in the youngest age group (< 40) and BRCA1/2 carriers.