Background Risk-reducing salpingo-oophorectomy is the 'gold standard' for preventing tubo-ovarian cancer in women at increased risk. However, when performed in pre-menopausal women, it results in premature menopause and associated detrimental health consequences. This, together with acceptance of the central role of the fallopian tube in etiopathogenesis of high-grade serous carcinoma, by far the most common type of tubo-ovarian cancer, has led to risk-reducing early salpingectomy with delayed oophorectomy being proposed as a two-step surgical alternative for pre-menopausal women declining/delaying oophorectomy.

Primary Objective To evaluate the impact on sexual function of risk-reducing early salpingectomy, within a two-step, risk-reducing, early salpingectomy with delayed oophorectomy tubo-ovarian cancer prevention strategy in pre-menopausal women at increased risk of tubo-ovarian cancer.

Study Hypothesis Risk-reducing early salpingectomy is non-inferior for sexual and endocrine function compared with controls; risk-reducing early salpingectomy is superior for sexual/endocrine function, non-inferior for quality-of-life, and equivalent in satisfaction to the standard risk-reducing salpingo-oophorectomy.

Trial Design Multi-center, observational cohort trial with three arms: risk-reducing early salpingectomy with delayed oophorectomy; risk-reducing salpingo-oophorectomy; controls (no surgery). Consenting individuals undergo an ultrasound, serum CA125, and follicle-stimulating hormone measurements and provide information on medical history, family history, quality-of-life, sexual function, cancer worry, psychological well-being, and satisfaction/regret. Follow-up by questionnaire takes place annually for 3 years. Women receiving risk-reducing early salpingectomy can undergo delayed oophorectomy at a later date of their choosing, or definitely by the menopause.

Major Inclusion/Exclusion Criteria Inclusion criteria: pre-menopausal; aged >30 years; at increased risk of tubo-ovarian cancer (mutation carriers or on the basis of a strong family history); completed their family (for surgical arms). Exclusion criteria: post-menopausal; previous bilateral salpingectomy or bilateral oophorectomy; pregnancy; previous tubal/ovarian/peritoneal malignancy; <12 months after cancer treatment; clinical suspicion of tubal/ovarian cancer at baseline.

Primary Endpoint Sexual function measured by validated questionnaires.

Sample Size 1000 (333 per arm).

Estimated Dates for Completing Accrual and Presenting Results It is estimated recruitment will be completed by 2023 and results published by 2027.

Trial Registration Number ISRCTN registry: 25 173 360 (https://doi.org/10.1186/ISRCTN25173360).