2022-RA-1161-ESGO The impact of oophorectomy on survival from breast cancer in patients with CHEK2 mutations

Introduction/BackgroundTo estimate the impact of oophorectomy and other treatments onthe survival of breast cancer patients with a CHEK2 mutation.MethodologyWomen with Stage I-III breast cancer who were treated at 17hospitals in Poland were tested for four founder mutations in the CHEK2 gene.974 women (10%) were positive for a CHEK2 mutation. Control patientswithout a CHEK2 mutation were selected from a database of patients treatedover the same time period. Information on treatments received and distantrecurrences were retrieved from medical records. Treatments includedchemotherapy, hormonal therapy (tamoxifen) and radiation therapy.Oophorectomies were performed for the treatment of breast cancer or for benignconditions. Dates of death were obtained from the Polish Vital StatisticsRegistry. Causes of death were determined by medical record review. Predictorsof survival were determined using the Cox proportional hazards model.ResultsIn all, 839 patients with a CHEK2 mutation were matched to 839patients without a mutation. The mean follow-up was 12.0 years. The 15-yearsurvival for CHEK2 carriers was 76.6% and the 15-year survival for non-carriercontrol patients was 78.8% (adjusted HR = 1.06; 95% CI: 0.84–1.34; P = 0.61).Among CHEK2 carriers, the 15-year survival for women who had anoophorectomy was 86.3% and for women who did not have an oophorectomywas 72.1% (adjusted HR = 0.59; 95% CI: 0.38–0.90; P = 0.02). Among controls,the 15-year survival for patients who had an oophorectomy was 84.5% and forwomen who did not have an oophorectomy was 77.6% (adjusted HR = 1.03;95% CI: 0.66–1.61; P = 0.90).ConclusionAmong women with breast cancer and a CHEK2 mutation,oophorectomy is associated with a reduced risk of death from breast cancer.