In a study reported in the Journal of Clinical Oncology, investigators from the Hereditary Breast Cancer Clinical Study Group found that women with ovarian cancer with pathogenic/likely pathogenic BRCA1/2 variants had low risk for subsequent breast cancer.
Study Details
The study involved an international cohort of 960 patients with a diagnosis of ovarian cancer who had BRCA1/2 variants, no other cancer history, and who had not undergone risk-reducing bilateral mastectomy. Women were followed for incident breast cancer from the date of ovarian cancer diagnosis or the date of baseline questionnaire (whichever came last); 5-, 10-, and 15-year cumulative risks of breast cancer were compared with a set of 741 age-matched BRCA1/2 carriers without ovarian cancer.
Study Findings
After a mean follow-up of 4.9 years, 41 (4.3%) of the 960 patients with ovarian cancer developed breast cancer. The actuarial cumulative breast cancer risks were 4.4%, 8.9%, and 11.5% at 5, 10, and 15 years, respectively. Death due to breast cancer occurred in three patients. Among the 741 age-matched BRCA carriers without ovarian cancer, 169 women (22.8%) developed breast cancer, with actuarial breast cancer risks of 20.9%, 38.6%, and 47.2% at 5, 10, and 15 years, respectively. The hazard ratio for breast cancer after an ovarian cancer diagnosis vs no ovarian cancer was 0.18 (95% confidence interval = 0.12–0.27, P < .0001).
The investigators concluded: “After ovarian cancer, BRCA carriers have a relatively low risk of breast cancer. Risk-reducing mastectomy should not be recommended routinely, but might be considered for long-term survivors. Magnetic resonance imaging surveillance and/or mammography is a realistic alternative.”
Steven A. Narod, MD, of Women’s College Research Institute, University of Toronto, Toronto, Canada, is the corresponding author for the Journal of Clinical Oncology article.
DISCLOSURE: The study was supported by the Canadian Institutes of Health Research, Canadian Cancer Society, Norwegian Cancer Society, and Canada Research Chairs Program. For full disclosures of the study authors, visit ascopubs.org.
