BRCA1 and peritoneum cancer: For BRCA1, RRBSO (1/449‐PPC) vs no RRBSO (21/367‐ovarian cancer), total follow‐up 5769.8 years, was associated with a HR for ovarian/peritoneal cancer of 0.014 (95% CI = 0.002‐0.106) (P < .001), and for BRCA2, RRBSO (2/357‐PPC) vs no RRBSO (9/347‐ovarian cancer), total follow‐up 4174.5 years, was associated with a HR for ovarian/peritoneal cancer of 0.072 (95% CI = 0.014‐0.366) (P = .002) (Figure 2A).