Ovarian cancer risk of Chinese women with BRCA1/2 germline pathogenic variants

Estimating the lifetime risk of ovarian cancer in Chinese women with BRCA1/2 germline pathogenic variants (PVs) is of great importance for the clinical management of BRCA1/2 carriers. This cohort study recruited 9903 unselected Chinese breast cancer patients whose BRCA1/2 status was determined. Of these, 3984 probands completed family history questionnaires, which investigated the health status of their relatives, including 11,997 female first-degree relatives. The ovarian cancer risk of BRCA1/2 germline pathogenic carriers was estimated using the ovarian cancer history of proband first-degree female relatives via the Kin-cohort method. Of the 3984 probands, 126 (3.2%) carried BRCA1 PVs, and 183 (4.6%) carried BRCA2 PVs. The estimated cumulative risks of ovarian cancer by age 70 were 15.3% (95% CI 8.4-18.6%) for BRCA1 carriers, 5.5% (95% CI 2.0-10.2%) for BRCA2 carriers, and 0.4% (95% CI 0.3-0.7%) for noncarriers. The cumulative risks of ovarian cancer were very low before the age of 40 for both BRCA1 and BRCA2 carriers and were an increase up to age 45. The cumulative ovarian cancer risk of BRCA1 carriers was approximately three times higher than that of BRCA2 carriers, and BRCA1 and BRCA2 carriers had 38- and 14-fold higher risks than non-BRCA carriers, respectively. The findings indicate that Chinese women with BRCA1/2 PVs have high risks of ovarian cancer in their lifetime, especially BRCA1 carriers. These results are useful for devising optimal strategies to reduce ovarian cancer risk in BRCA1/2 carriers.