TAMOXIFEN AND CHEMOTHERAPY FOR LYMPH NODE-NEGATIVE, ESTROGEN RECEPTOR-POSITIVE BREAST-CANCER

Background: The B-20 study of the National Surgical Adjuvant Breast an d Bowel Project (NSABP) was conducted to determine whether chemotherap y plus tamoxifen would be of greater benefit than tamoxifen alone in t he treatment of patients with axillary lymph node-negative, estrogen r eceptor-positive breast cancer. Methods: Eligible patients (n = 2306) were randomly assigned to one of three treatment groups following surg ery. A total of 771 patients with followup data received tamoxifen alo ne; 767 received methotrexate, fluorouracil, and tamoxifen (MFT); and 768 received cyclophosphamide, methotrexate, fluorouracil, and tamoxif en (CMFT). The Kaplan-Meier method was used to estimate disease-free s urvival, distant disease-free survival, and survival. Reported P value s are two-sided. Results: Through 5 years of follow-up, chemotherapy p lus tamoxifen resulted in significantly better disease-free survival t han tamoxifen alone (90% for MFT versus 85% for tamoxifen [P = .01]; 8 9% for CMFT versus 85% for tamoxifen [P = .001]). A similar benefit wa s observed in both distant disease-free survival (92% for MFT versus 8 7% for tamoxifen [P = .008]; 91% for CMFT versus 87% for tamoxifen [P = .006]) and survival (97% for MFT versus 94% for tamoxifen [P = .05]; 96% for CMFT versus 94% for tamoxifen [P = .03]). Compared with tamox ifen alone, MFT and CMFT reduced the risk of ipsilateral breast tumor recurrence after lumpectomy and the risk of recurrence at other local, regional, and distant sites. Risk of treatment failure was reduced af ter both types of chemotherapy, regardless of tumor size, tumor estrog en or progesterone receptor level, or patient age; however, the reduct ion was greatest in patients aged 49 years or less. No subgroup of pat ients evaluated in this study failed to benefit from chemotherapy. Con clusions: Findings from this and other NSABP studies indicate that pat ients with breast cancer who meet NSABP protocol criteria, regardless of age, lymph node status, tumor size, or estrogen receptor status, ar e candidates for chemotherapy.