Specialist oncological surgery for removal of the ovaries and fallopian tubes in BRCA1 and BRCA2 pathogenic variant carriers may reduce primary peritoneal cancer risk to very low levels

Menée en Angleterre à partir de données d'un registre régional portant sur 891 femmes porteuses d'une mutation BRCA et ayant subi une salpingo-ovariectomie prophylactique bilatérale et sur 1 302 témoins n'ayant pas eu recours à cette opération (âge médian lors de la chirurgie : 45 ans), cette étude analyse l'efficacité de cette opération sur la réduction du risque de cancer séreux de l'ovaire de haut grade ou du péritoine

Résumé en anglais

Risk-reducing bilateral salpingo-oophorectomy (RRBSO) is highly effective for the prevention of high-grade serous ovarian cancer (HGSOC) in BRCA1/2 pathogenic variant carriers (PVCs), but does not completely eliminate future risk of primary peritoneal cancer (PPC). The requirement to completely remove fallopian tubes at RRBSO and carefully exclude occult cancer/serous tubal intraepithelial carcinoma (STIC) lesions may not have been appreciated historically. We calculated rates of HGSOC and PPC in confirmed BRCA1/2 PVCs registered on the regional database in those who did (cases) and did not (controls) undergo RRBSO after genetic testing. Expected annual rates of ovarian/peritoneal cancer were 1% for BRCA1 ≥ 35 years and 0.5% for BRCA2 ≥ 45 years. Follow-up before 35/45 years was “risk free” and lead time excluded RRBSO <35 years and <45 years for BRCA1 and BRCA2, respectively. Women were followed from personal mutation report (controls) or RRBSO (cases) to death, ovarian/peritoneal cancer or last follow-up, whichever was sooner. In total, 891 cases (BRCA1 = 468, BRCA2 = 423) and 1302 controls had follow-up ≥35 years (BRCA1 = 736) and ≥45 years (BRCA2 = 566), respectively, over a total of 7261.1 risk eligible years (mean = 8.15 years). Twenty-one occult ovarian cancers were found at RRBSO (2.4%), 16 at stage 1. Post RRBSO, 56.97 ovarian/peritoneal cancers were expected but only 3 were observed (HR = 0.053; 95% CI = 0.013-0.14), with combined Kaplan-Meier analysis HR = 0.029 (95% CI = 0.009-0.100, P < .001). Risk reduction was greater in specialist (HR = 0.03; 95% CI = 0.001-0.13) compared to non-specialist centres (HR = 0.11; 95% CI = 0.02-0.37) (P = .07). In controls, 23.35 ovarian/peritoneal cancers were expected with 32 observed (HR = 1.37; 95% CI = 0.95-1.91). RRBSO <35/<45 years reduces the risk of ovarian/peritoneal cancer by 95% in BRCA1/2 PVCs and may be greater in specialist centres.