Significance of prostate/pancreatic/skin cancer family history for detecting BRCA2 pathogenic variant careers among patients with breast cancer.

BACKGROUND: When considering BRCA1/2 genetic testing for diagnosis of hereditary breast and ovarian cancer (HBOC), family history (FH) of breast and ovarian cancer is commonly considered. However, FH of other HBOC-related cancers, such as prostate, pancreatic, and skin cancer (malignant melanoma), is often overlooked. METHODS: Among 945 patients who received genetic testing of BRCA1/2 at our hospital between October 2010 and September 2021, we compared the FH of 123 patients diagnosed with HBOC and 669 other patients who had breast cancer and had a documented FH. This study focused on the FH of HBOC-related cancers such as breast, ovarian, prostate, pancreatic, and skin cancer, as well as colorectal, gastric, liver, lung, and uterine cancers, which are common among Japanese, and other cancers. RESULTS: FH of prostate, pancreatic, and skin cancer was significantly higher in the BRCA2 pathogenic variant (PV) cases than in the wild-type (WT) cases. The mean number of family members are as follows: BRCA1 PV/ BRCA2 PV/ WT; prostate cancer: 0.05/ 0.34/ 0.09 (P < 0.0001, Kruskal-Wallis multiple comparisons test), pancreatic cancer: 0.13/ 0.21/ 0.10 (P = 0.01637), and skin cancer: 0.03/ 0.07/ 0.01 (P = 0.00129), respectively. CONCLUSIONS: When considering BRCA1/2 genetic testing, FH of prostate, pancreatic, and skin cancers may also be examined as HBOC-related cancers to provide testing for patients who would benefit from it. However, further studies for the association between skin cancer and HBOC will be required because it has not been reported in Japan.