Adjuvant CMFVP versus tamoxifen versus concurrent CMFVP and tamoxifen for postmenopausal, node-positive, and estrogen receptor-positive breast cancer patients: a Southwest Oncology Group study

Abstract

Purpose: To compare chemohormonal therapy, chemotherapy alone, and hormonal therapy alone in postmenopausal patients with estrogen receptor (ER)-positive operable breast cancer and positive axillary nodes with respect to survival and disease-free survival (DFS).

Patients and methods: Eight hundred ninety-two postmenopausal women with ER-positive, node-positive breast cancer were enrolled by the Southwest Oncology Group (SWOG) from July 1979 to March 1989 and 74 by the Eastern Cooperative Oncology Group (ECOG) between June 1987 and March 1989. Patients were stratified according to number of involved nodes and type of primary surgery and randomized to receive the following: (1) tamoxifen 10 mg twice daily by mouth for 1 year; (2) cyclophosphamide 60 mg/m2/d by mouth for 1 year, methotrexate 15 mg/m2 intravenously (IV) weekly for 1 year, fluorouracil (5-FU) 400 mg/m2 IV weekly for 1 year, vincristine .625 mg/m2 IV weekly for the first 10 weeks, and prednisone during weeks 1 to 10 with doses decreasing from 30 mg/m2 to 2.5 mg/m2 (CMFVP); or (3) the combination of tamoxifen and CMFVP.

Results: The median follow-up duration is 6.5 years, with a maximum of 12.8 years. Treatment arms are not significantly different with respect to either survival or DFS (log-rank, 2 df, P = .82 and .23, respectively). The 5-year survival rate is 77% for the tamoxifen arm, 78% for CMFVP, and 75% for the combination. No significant differences were observed in node or receptor level subsets. Severe or worse toxicity was experienced by 56% of patients on CMFVP and 61% on CMFVP plus tamoxifen, compared with 5% on tamoxifen alone.

Conclusion: CMFVP chemotherapy, either alone or in combination with tamoxifen, has not been shown to be superior to tamoxifen alone in the treatment of postmenopausal women with node-positive, ER-positive, operable breast cancer.