Tamoxifen and chemotherapy for axillary node-negative, estrogen receptor-negative breast cancer: Findings from National Surgical Adjuvant Breast and Bowel Project B-23

Purpose: Uncertainty about the relative worth of doxorubicin/cyclophosphami de (AC) and cyclophosphamide/methotrexate/fluorouracil (CMF), as well as do ubt about the propriety of giving tamoxifen (TAM) with chemotherapy to pati ents with estrogen receptor negative tumors and negative axillary nodes, pr ompted the National Surgical Adjuvant Breast and Bowel Project to initiate the B-23 study. Patients and Methods: Patients (n = 2,008) were randomly assigned to CMF pl us placebo, CMF plus TAMI AC plus placebo, or AC plus TAM. Six cycles of CM F were given for 6 months; four cycles of AC were administered for 63 days. TAM was given daily for 5 years. Relapse-free survival (RFS), event-free s urvival (EFS), and survival (S) were determined by using life-table estimat es. Tests for heterogeneity of outcome used log-rank statistics and Cox pro portional hazards models to detect differences across all groups and accord ing to chemotherapy and hormonal therapy status. Results: No significant difference in RFS, EFS, or S was observed among the four groups through 5 years (P =.96,.8, and .8, respectively), for those a ged less than or equal to 49 years (P = .97, .5, and .9, respectively), or for those aged greater than or equal to 50 years (P = .7, .6, and .6, respe ctively). A comparison between all CMF- and all AC-treated patients demonst rated no significant differences in RFS (87% at 5 years in both groups, P = .9), EFS (83% and 82%, P = .6), or S (89% and 90%, P = .4). There were no s ignificant differences in RFS, EFS, or S between CMF and AC in patients age d less than or equal to 49 or greater than or equal to 50 years. No signifi cant difference in any outcome was observed when chemotherapy-treated patie nts who received placebo were compared with those given TAM. RFS in both gr oups was 87% (P = .6), 87% in patients aged 49 (P =.9), land 88% and 87%, r espectively (P = .4), in those aged greater than or equal to 50 years. Conclusion: There was no significant difference in the outcome of patients who received AC or CMF. TAM with either regimen resulted in no significant advantage over that achieved from chemotherapy alone.