Introduction/Background*Ovarian cancer (OC) in BRCA mutation-carriers is typically diagnosed clinically at >=stage 3c, with consequent poor prognosis. Risk-reducing salpingo-oophorectomy (RRSO) is recommended for BRCA mutation-carriers as the only proven method of OC prevention. Women who defer RRSO to permit child-bearing/prevent premature menopause would benefit from surveillance which can downstage OC occurring prior to RRSO. We wanted to establish the ‘real world’ performance of OC surveillance which we have previously shown downstages OC in clinical trials.

Methodology 875 female BRCA mutation-carriers were recruited at 13 UK centres and via a media campaign and underwent 4-monthly surveillance with the Risk of Ovarian Cancer Algorithm (ROCA) blood test. They had a 6 week repeat test if their ROCA score was >1 in 1000, and a transvaginal scan (TVS) in addition, if their risk was > 1 in 500. Women with a score >1 in 33 or those with concerning TVS were referred to a rapid access clinic to rule out OC. RRSO was encouraged throughout the program. Participants were followed via questionnaires, notification by centres/GPs and direct contact. Surveillance performance was calculated after censoring 4 months after prior screen, with modelling of occult cancers detected at RRSO. Incremental cost-effectiveness was calculated using a Markov population cohort simulation.

Result(s)*8 OCs occurred during 1277 women screen years; 2 occult OCs at RRSO (both stage 1a), 6 screen-detected OCs (3 prevalent; stage 2a, 3aii and 3c, 3 incident; stage 1a, 3b and 4b). 4 of 6 (67%) screen-detected OCs were diagnosed at stages <3c. 7 of 8 (87.5%) screen-detected cancers were completely cytoreduced. There were no interval cancers. Modelled sensitivity, specificity, PPV and NPV for OC were 87.5% (CI, 47.3–99.7), 99.9%(99.9–100), 75%(34.9–96.8) and 99.9%(99.9–100) respectively. Economic modelling indicated that surveillance would be cost-saving within the UK National Health Service.

Conclusion*OC surveillance for women declining RRSO in a ‘real-word’ setting is feasible and equally effective as in research trials, resulting in successful downstaging with likely clinical benefit and healthcare cost savings. Whilst RRSO remains the recommended management for BRCA-carriers, ROCA-based surveillance is a viable interim option for those who defer such surgery.