Chemotherapy with cyclophosphamide, adriamycin, and 5-fluorouracil compared to chemotherapy plus hormonal therapy with tamoxifen in the treatment of advanced breast cancer: an interim analysis.

Between February 1980 and August 1982, the Cancer and Leukemia Group B (CALGB) performed a randomized study aimed to compare chemotherapy with CAF (Cyclophosphamide, Adriamycin, 5-Fluorouracil) versus the same chemotherapeutic regimen plus tamoxifen (T-CAF) in stage IV breast cancer patients. Patients were stratified on the basis of menopausal status, estrogen receptors (ER) status, dominant site of metastasis and prior adjuvant treatment. Overall 474 patients were entered into the study of whom 433 were assessable for response. 314 patients were postmenopausal, 85 premenopausal and 34 patients were unknown as far menopausal status was concerned. No difference was evident among postmenopausal patients in overall response rate and duration of responses between T-CAF and CAF (52% vs 50% respectively). Similarly no difference was shown among premenopausal patients, response rates being 63% with T-CAF and 60% with CAF. Lack of benefit from adding T to chemotherapy was seen also according to the different strata, including patients with ER positive tumors. The failure for this combination to be synergistic might reflect an effect of T on tumor kinetics interfering with the activity of chemotherapy.