A new study has found that women in families with a harmful BRCA1 or BRCA2 mutation continue to have increasing risks of breast and ovarian cancer in their seventies. Accurate estimates of lifetime risks of breast and ovarian cancer are important for cancer-related decision-making in women from BRCA1/2 families. The study compared breast and ovarian cancer rates in BRCA1/2 mutation families in the northern Netherlands to those of the general population in this region. The study included 1,188 female mutation carriers and first-degree female relatives in 185 families with a harmful BRCA1 or BRCA2 mutation. Breast cancer, contralateral breast cancer and ovarian cancer incidence were assessed.

The cumulative incidence of breast cancer by age 70 was 71.4% in BRCA1 and 87.5% in BRCA2 mutation carriers. The cumulative incidence of ovarian cancer by age 70 was 58.9% in BRCA1 and 34.5% in BRCA2 mutation carriers. The incidence of both types of cancer continued to rise during the seventh decade of life in these families. In the case of breast cancer, there was an increase of 6.3% for BRCA1 carriers and 24.2% for BRCA2 in the cumulative incidence in the seventh decade. In the case of ovarian cancer, the increase in the seventh decade was 17.3% for BRCA1 carriers and 15.1% for BRCA2. The 10-year risk for contralateral breast cancer was found to be 34.2% in BRCA1 families and 29.2% in BRCA2 families. The authors conclude that the incidence of breast and ovarian cancer in BRCA2 carriers and of ovarian cancer in BRCA1 carriers is still high after 60 years. This may justify intensive breast screening as well as removal of the ovaries even after age 60. The risk of contralateral breast cancer also rises approximately 3% per year, which may affect preventive choices.