First-degree family history of prostate cancer is associated the risk of breast cancer and ovarian cancer

The evidence for associations between family history of prostate cancer and the risk of breast cancer and ovarian cancer is inconclusive. The first systematic review and meta-analysis of studies was conducted to assess the risk of breast cancer and ovarian cancer associated with a family history of prostate cancer. A literature search was conducted using MEDLINE, Embase and Web of science databases up to January 31, 2019. Data were screened and extracted independently by 2 reviewers. The pooled risk ratio (RR) and its 95% confidence interval (CI) were calculated using random-effects models. The GRADE approach was used to assess the quality of evidence. Nine observational studies including 8,011,625 individuals were included in the meta-analysis. The meta-analysis showed that family history of prostate cancer in first-degree relatives was associated with an increased risk of breast cancer (RR 1.12, 95%CI 1.09 to 1.14) with moderate quality evidence, subgroup analysis showed consistent results. Compared with no family history of prostate cancer, history of prostate cancer in first-degree relatives was associated with a slight risk of ovarian cancer (1.10, 95%CI 1.01 to 1.20) with moderate quality evidence. Family history of prostate cancer among sibling was associated with a 17% increased risk of ovarian cancer (95% CI 1.03 to 1.34), however, no significant association was found between family history of prostate cancer among parent and risk of ovarian cancer (RR 1.19, 95% CI 0.84 to 1.70). This review demonstrates that women with a family history of prostate cancer in first-degree relatives was associated with an increased risk of breast cancer and ovarian cancer. These findings may aid in screening, earlier detection and treatment of women with a family history of prostate cancer in first-degree relatives.