Oncogynecology

Breast and Ovarian Cancer Risk in BRCA1 and BRCA2 Mutation Carriers: Expert Processing and Assessment – JAMA journal, June 20, 2017; 317:2402

A multinational prospective cohort study provides long-term cancer incidence estimates in this high-risk population.

Accurate age-related risk assessment of breast and ovarian cancer can facilitate counseling for evaluating BRCA mutation carriers. Researchers observed women with family members having tumors, primarily in the UK, Netherlands, and France. Women were included in this cohort from 1997 to 2011 and had not undergone breast or gynecological surgery; follow-up continued until 2013 (average 5 years). A total of 6,036 women carriers of BRCA1 mutations and 3,820 women carriers of BRCA2 mutations were under observation (mean age at the start of the study was 38 years).

The cumulative risk for breast cancer at age 80 was 72% in BRCA1 carriers and 69% in BRCA2 carriers; for ovarian cancer, the cumulative risk was 44% and 17%, respectively. The peak incidence of breast cancer occurred between ages 41–50 for BRCA1 carriers (28 per 1,000 person-years) and ages 51–60 (31 per 1,000) for BRCA2 carriers. The prevalence of ovarian cancer was 3.6 times higher among BRCA1 than BRCA2 carriers, with peak incidence among women aged 61–70 regardless of mutation type. The cumulative risk of contralateral breast cancer 20 years after the first breast cancer diagnosis was 40% for BRCA1 carriers and 26% for BRCA2 carriers. For BRCA1 and BRCA2 carriers, breast cancer risk increased with the number of first- and second-degree relatives with breast cancer, respectively. In contrast, ovarian cancer risk did not vary by family history.

Since most participants in this study had no cancer history and mutation carriership was identified through preventive screening due to family history, these risk estimates should generally be useful for BRCA carriers identified through such screening. In particular, these findings may inform surveillance and risk-reduction strategies (including chemoprevention and surgery) decisions for these high-risk women.