Risk-reducing Strategies, Including Fimbriectomy, in Women With a Germline Mutation Predisposing to Ovarian or Pelvic Cancer

• The FIMBRIMENOP-2402 study is a pragmatic, multicenter, interventional trial (RIPH1) designed to evaluate long-term management strategies for reducing cancer risk in premenopausal women genetically predisposed to tubo-ovarian or primary peritoneal carcinoma. Women carrying mutations in BRCA1, BRCA2, RAD51C, RAD51D, or PALB2 genes are the primary focus of this investigation.

• Objectives

The primary objective is to evaluate, on a long-term horizon, the control of the risk of advanced stage tubo-ovarian or primary peritoneal carcinoma according to the chosen care pathway, and more specifically whether F-DO is non inferior to BSO, in women with a germline mutation predisposing to the risk of high grade serous tubo-ovarian or primary peritoneal carcinoma.

The study aims to determine whether F-DO is non-inferior to BSO in controlling the risk of advanced-stage tubo-ovarian or primary peritoneal carcinoma in high-risk women.

The secondary objectives include evaluating the benefit-risk ratio of these approaches by assessing:

• Menopause-related side effects, such as cardiovascular and osteoporosis-related events.

• Surgical complications and overall survival.

• Long-term oncological outcomes, including breast cancer risks.

• Patient-reported preferences and compliance with the chosen pathway.

The study will also contribute to a prospective meta-analysis of similar international studies.

• Design and Methodology

The study employs a non-randomized controlled preference design, allowing participants to choose their preventive surgical strategy after informed counseling with oncogeneticists and gynecologic surgeons. This approach promotes patient autonomy while reflecting real-world clinical decision-making. Participants may revise their choice at any time before the first surgical intervention. The actual treatment received or the final preference will define the "care pathway".

• Population and Recruitment

The study will enroll 1,100 premenopausal women aged 35-50 years from multiple French centers, all of whom are at an elevated genetic risk for tubo-ovarian or primary peritoneal carcinoma. Recruitment is expected to span five years, with follow-up continuing until participants reach 70 years of age.

• Data Collection and Follow-Up

Data collection integrates multiple sources to ensure comprehensive coverage of outcomes:

1. Annual Clinical Assessments: Participants undergo routine clinical evaluations, including physician visits, medical reports, and online questionnaires or phone interviews.

2. Regional Oncogenetic Networks: Data from regional networks are incorporated to monitor oncological events and compliance.

3. French Administrative Health Database (SNDS): Extraction of anonymized health records ensures the completeness of reported events and reduces logistical complexity.

   • Endpoints :

   • Primary Endpoint :

The incidence of advanced-stage (stage III or IV) tubo-ovarian or primary peritoneal carcinoma, measured as the time from study entry to the occurrence of cancer, with death without cancer as a competing event. Censoring will occur at the last follow-up visit for women without cancer.

• Secondary Endpoints include :

• Incidence of tubo-ovarian carcinoma at any stage, breast cancer, cardiovascular and osteoporosis-related events.

• Age at menopause.

• Surgical complications within 30 days post-surgery, graded per NCI-CTCAE V5.0.

• Statistical Analysis

The final analysis will occur when all participants have been followed for 35 years, with interim analyses planned every six years or upon reporting of 10 events. Data will be analyzed to compare oncological outcomes, quality of life, and survival between the F-DO and BSO groups. Biases inherent in the preference design will be addressed through appropriate statistical modeling.

• Ethical Considerations

The study adheres to French regulatory requirements, including patient data confidentiality under the GDPR and ethical review by relevant committees. Informed consent will be obtained from all participants, with clear communication of risks and benefits.

By evaluating the efficacy and safety of F-DO, this study has the potential to redefine preventive surgical strategies, optimizing outcomes for women at high genetic risk of ovarian cancer.