Adjuvant therapy with a doxorubicin regimen and long-term tamoxifen in premenopausal breast cancer patients: an Eastern Cooperative Oncology Group trial.

Abstract

PURPOSE A randomized trial was performed in premenopausal postoperative women with ipsilateral axillary node-positive (N+) breast carcinoma and known estrogen receptor (ER) status to assess the efficacy of an Adriamycin (doxorubicin; Adria Laboratories, Columbus, OH)-based induction regimen and 5 or more years of tamoxifen (Tam). PATIENTS AND METHODS Patients received 12 28-day cycles of cyclophosphamide 100 mg/m2 orally days 1 to 14, methotrexate 40 mg/m2 intravenously (IV) days 1 and 8, fluorouracil 600 mg/m2 IV days 1 and 8, prednisone 40 mg/m2 orally days 1 to 14, and Tam 10 mg orally twice daily (CMFPT), or the same regimen plus halotestin 10 mg orally twice daily (CMFPTH) alternating monthly with 22-day cycles of vinblastine 4.5 mg/m2 IV day 1, Adriamycin 45 mg/m2 IV day 1, thiotepa 12 mg/m2 IV day 1, halotestin, and Tam (ALTER). Prednisone in the ALTER regimen was stopped after the second CMFPTH cycle. After 12 cycles, patients were again randomized to stop or continue Tam. After 5 years, patients on Tam were again randomized to continue or stop Tam; the results from this randomization are still coded. Among 533 analyzed induction cases, 263 received CMFPT and 270 ALTER. Among 396 analyzed maintenance cases, 201 continued Tam and 195 were observed. Pretreatment characteristics were balanced among treatments. The median follow-up times are 5.1 years for induction and 4.1 years for maintenance. RESULTS The time to relapse (TTR) was superior for the ALTER regimen (P = .04) and for the maintenance Tam (P = .05). Overall survival comparisons between the regimens are not statistically different. A longer TTR was associated with decreasing nodal involvement, ER+ status, and increasing age. The favorable effects of decreasing nodal involvement and ER+ status carried over to survival; a progesterone receptor-positive (PgR+) status and decreasing tumor size were also associated with longer survival. Development of amenorrhea was associated with improved TTR and survival. Toxicity was similar for the two induction regimens and for the two maintenance regimens. Overall relapse patterns were similar among the induction regimens, but continuing Tam led to fewer locoregional relapses. CONCLUSION The results suggest significant overall TTR therapeutic benefits of an Adriamycin-containing alternating induction regimen and of continuing maintenance Tam therapy for at least 5 years.