Approximately 5 % of invasive breast cancers are attributable to a germline pathogenic variant (herein referred to as mutations) in the BRCA1 or BRCA2 genes [1]. Women who carry a mutation have cumulative risks of developing breast cancer to age eighty of 72 % for BRCA1 and 69 % for BRCA2. The cumulative risk of ovarian or fallopian tube (ovarian hereafter) cancer are 44 % and 17 % for BRCA1 and BRCA2, respectively [2]. For women with a BRCA1 mutation, the average age at breast cancer diagnosis is 42.5 years, and for BRCA2 carriers is 46.8 years [3]. Previous research has shown that breast-cancer specific survival is similar or better than in women with non-hereditary breast cancer [[4], [5], [6], [7], [8], [9], [10], [11]]. Due to the relatively young age at diagnosis and high survival rates, it is important to consider the risks of other cancers after breast cancer for women with a BRCA1 or BRCA2 mutation.

For women with a BRCA1 or BRCA2 mutation who are diagnosed with ovarian cancer, five-year survival rates are low [12,13]. As a result, most clinical guidelines for management of women with BRCA1 and BRCA2 mutations (including the National Comprehensive Cancer Network) recommend risk-reducing salpingo-oophorectomy (RRSO) for the reduction in risk of ovarian cancer. This recommendation is based on evidence that RRSO significantly reduces the risk of ovarian/fallopian cancer as well as all-cause mortality and breast cancer-specific mortality [14]. In addition, we have reported that RRSO significantly reduces the risk of contralateral breast cancer in women with BRCA-associated breast cancer [15].

For various reasons, not all women with breast cancer and a BRCA mutation elect for RRSO. This may be the result of genetic testing not being done at the time of a breast cancer diagnosis, and thus, the woman is not aware of her future risk of ovarian cancer, a disease with a high case-fatality rate. It is also possible that the patients and/or treating physicians are focused on the treatment of the breast cancer and are less focused on preventive measures. To help inform patients, we conducted a real-world analysis of women with BRCA-breast cancer and with two intact ovaries to estimate the risk of ovarian cancer after breast cancer. We also sought to identify risk factors associated with the development of ovarian cancer in women with a previous diagnosis of breast cancer. We also compared the risks of ovarian cancer for women with a BRCA mutation with and without a history of breast cancer.