Purpose: To compare the efficacy of ovarian ablation versus chemotherapy in early breast cancer patients with hormone receptor-positive disease.
Patients and methods: We conducted an open, randomized, multicenter trial including premenopausal breast cancer patients with hormone receptor-positive tumors and either axillary lymph node metastases or tumors with a size of 5 cm or more. Patients were randomly assigned to ovarian ablation by irradiation or to nine courses of chemotherapy with intravenous cyclophosphamide, methotrexate, and fluorouracil (CMF) administered every 3 weeks.
Results: Between 1990 and May 1998, 762 patients were randomly assigned, and the present analysis is based on 358 first events. After a median follow-up time of 8.5 years, the unadjusted hazard ratio for disease-free survival in the ovarian ablation group compared with the CMF group was 0.99 (95% CI, 0.81 to 1.22). After a median follow-up time of 10.5 years, overall survival (OS) was similar in the two groups, with a hazard ratio of 1.11 (95% CI, 0.88 to 1.42) for the ovarian ablation group compared with the CMF group.
Conclusion: In this study, ablation of ovarian function in premenopausal women with hormone receptor-positive breast cancer had a similar effect to CMF on disease-free and OS. No significant interactions were demonstrated between treatment modality and hormone receptor content, age, or any of the well-known prognostic factors.