Factors influencing uptake and timing of risk reducing salpingo-oophorectomy in women at risk of familial ovarian cancer: a competing risk time to event analysis

Objective: To evaluate factors affecting uptake of risk-reducing salpingo-oophorectomy (RRSO) over time in women at high-risk of familial ovarian cancer.

Design: Prospective observational cohort.

Setting: Tertiary high-risk familial gynaecological cancer clinic.

Population/sample: New clinic attendees between March 2004 and November 2009, fulfilling the high-risk criteria for the UK Familial Ovarian Cancer Screening Study.

Methods: Risk management options discussed included RRSO and ovarian surveillance. Outcome data were analysed from a bespoke database. The competing risk method was used to model the cumulative incidence function (CIF) of RRSO over time, and the sub-hazard ratio (SHR) was used to assess the strength of the association of variables of interest with RRSO. Gray's test was used to evaluate the difference in CIF between two groups and multivariable competing risk regression analysis was used to model the cumulative probabilities of covariates on the CIF.

Results: Of 1133 eligible women, 265 (21.4%) opted for RRSO and 868 (69.9%) chose screening. Women undergoing RRSO were older (49 years, interquartile range 12.2 years) than those preferring screening (43.4 years, interquartile range 11.9 years) (P < 0.0005). The CIF for RRSO at 5 years was 0.55 (95% CI 0.45-0.64) for BRCA1/2 carriers and 0.22 (95% CI 0.19-0.26) for women of unknown mutation status (P < 0.0001); 0.42 (95% CI 0.36-0.47) for postmenopausal women (P < 0.0001); 0.29 (95% CI 0.25-0.33) for parity ≥1 (P = 0.009) and 0.47 (95% CI 0.39-0.55) for a personal history of breast cancer (P < 0.0001). Variables of significance from the regression analysis were: a BRCA1/2 mutation (SHR 2.31, 95% CI 1.7-3.14), postmenopausal status (SHR 2.16, 95% CI 1.62-2.87)) and a personal history of breast cancer (SHR 1.5, 95% CI 1.09-2.06).

Conclusions: Decision-making is a complex process and women opt for surgery many years after initial risk assessment. BRCA carriers, postmenopausal women and women who had breast cancer are significantly more likely to opt for preventative surgery.