Purpose: Although hormonal therapy represents standard therapy for metastatic hormone-sensitive disease, many patients receive initial chemotherapy because of the location, bulk, or aggressiveness of their disease. It is uncertain whether simultaneous hormonal therapy provides additional benefit compared with chemotherapy alone. Eastern Cooperative Oncology Group trial E3186 was initiated to explore this question.
Patients and methods: Between January 1988 and December 1992, 231 patients with estrogen receptor (ER)-positive or ER-unknown metastatic breast cancer were randomized to receive either chemotherapy (cyclophosphamide, doxorubicin, and fluorouracil ¿CAF) or chemohormonal therapy (CAF plus tamoxifen and Halotestin ¿fluoxymesterone; Pharmacia-Upjohn, Kalamazoo, MI ¿CAFTH) as front-line therapy for metastatic breast cancer. Patients who experienced a complete response to induction therapy either received or did not receive maintenance cyclophosphamide, methotrexate, fluorouracil, prednisone, and TH as a secondary randomization.
Results: The response rates (complete response and partial response) of patients who received CAF and CAFTH were similar (69.2% v 68.9%, respectively; P =.99). Time to treatment failure (TTF) was slightly longer for patients who received chemohormonal therapy compared with chemotherapy alone patients (13.4 months v 10.3 months, respectively; P =.087), and TTF was significantly longer in ER-positive compared with ER-negative patients (17.4 months v 10.3 months, respectively; P =.048). However, ER status had no effect on overall survival (30.0 months for CAF v 29.3 months for CAFTH).
Conclusion: In patients with potentially hormone-sensitive metastatic breast cancer, chemohormonal therapy prolongs TTF for ER-positive patients without improving overall survival.