BRCA2 and peritoneum cancer: However, it should be emphasized, that while there are thousands of examined patients and mean follow-up time from prophylactic surgery to the diagnosis of peritoneal cancer exceeds 6 years, the proportion of mutations in both BRCA genes found in patients with primary peritoneal cancer diagnosed after salpingo-oophorectomy has evidently changed – 28 BRCA1 vs. BRCA2 [21].