• Individuals 35-50 years of age, inclusive

• Patients who will undergo risk-reducing salpingo-oophorectomy (RRSO) (for the BSO arm) and patients who have declined or elected to defer BSO after proper counselling to clearly explain the standard of care for BRCA1 mutation carriers and are undergoing salpingectomy (for the BLS arm with delayed oophorectomy arm). Concurrently planned hysterectomy with either arm is permitted

• At least one intact ovary and fallopian tube is in situ at the time of counseling, consent, and registration. Prior hysterectomy is allowed provided it did not include bilateral salpingectomy. Prior tubal ligation is allowed if one ovary and fallopian tube (with fimbria not removed) are present

• Positive Clinical Laboratory Improvement Act (CLIA)-approved test results for pathogenic or likely pathogenic germline BRCA1 mutation in the patient. Documentation of the result is required

• Patients may be premenopausal or menopausal

• Pelvic ultrasound (transvaginal imaging preferred, but transabdominal imaging is acceptable) or pelvic MRI and CA-125 within 180 days of registration

• The patient or a legally authorized representative must provide study-specific informed consent prior to study entry

• Individuals who are currently pregnant or plan to become pregnant in the future through assisted reproductive technologies and who have received proper counseling are eligible. Individuals who are currently pregnant and plan bilateral salpingectomy at the time of a planned cesarean section are eligible. Patients must understand that they will not be able to become pregnant naturally in the future