Design: Multi-centre, observational cohort controlled study with three arms: risk reducing early salpingectomy with delayed oophorectomy (RRESDO); risk reducing salpingo-oophorectomy (RRSO); controls (no surgery).

Inclusion criteria: Premenopausal women; >30 years; at increased risk of ovarian cancer (mutation carriers or on the basis of a strong family history; completed their family (for surgical arms).

Exclusion criteria: Postmenopausal women; previous bilateral salpingectomy or bilateral oophorectomy; pregnancy; previous tubal/ovarian/peritoneal malignancy; <12 months post cancer treatment; clinical suspicion of tubal/ovarian cancer at baseline.

Recruitment: Through NHS cancer genetics/high-risk familial cancer clinics/general gynaecology clinics/gynaecological oncology clinics/GP surgeries/clinical referrals/supporting charities/self-referral.

Primary outcome: Sexual function.

Secondary outcomes: Endocrine function/menopause; regret/satisfaction; surgical morbidity; quality of life/psychological health; number of intraepithelial carcinomas/invasive cancers; utility scores for early-salpingectomy; cost-effectiveness; decision making; health and well being.

Recruitment: Participants will be identified through NHS cancer genetics/ high-risk familial cancer clinics, general gynaecology clinics, gynaecological oncology clinics, GP-surgeries, clinical referrals, supporting charities or by self-referral.  Interested participants will receive thorough counselling and Participation Information Sheets for informed decision making.

Interventions: Participants can choose any one of the three study arms (a) RRES and DO; (b) RRSO; or (c) Controls (no surgery). Consenting individuals for the surgical arms will undergo a hormonal profile (FSH), ultrasound, CA125 and complete questionnaires collecting information on medical history, family history, quality of life, sexual function, cancer worry, psychological well-being and satisfaction/regret. All women undergoing surgery will have cytological and histological assessment using a SEE-FIMM protocol and will undergo central pathology review. Post-surgery FSH levels will be tested and follow up questionnaires sent at 3 months and annually. Controls will not undergo surgery, and will have their FSH levels checked and complete questionnaires at baseline and annually for three years. A small number of women will be invited to attend face to face/telephone semi-structured in depth interviews to determine attitudes towards RRESDO (qualitative sub-study). This will help address the paucity of qualitative data on acceptability.

For further details please see our study factsheet or view details of the study on the ISRCTN registry.