Comparison of cyclical tamoxifen and megestrol acetate with tamoxifen alone in advanced breast cancer

First-line treatment with mitoxantrone, methotrexate, vincristine, and carboplatine (MIMOC) plus cyclical hormonotherapy with tamoxifen and megestrol acetate in advanced breast cancer

Fifty patients with stage IIIB and IV breast cancer entered a prospective study receiving combination chemotherapy consisting of mitoxantrone (8 mg/m2) on day 1, methotrexate (30 mg/m2) on day 1, vincristine (1 mg/m2) on day 2, and carboplatine (250 mg/m2) on day 2 (MIMOC), plus cyclical hormonotherapy with tamoxifen (20 mg daily, days 1-10) and megestrol acetate (160 mg daily, days 11-21). The regimen was repeated every 3 weeks. None had received chemotherapy for advanced disease, although 17 patients had previously received adjuvant chemotherapy and 21 had received adjuvant hormonotherapy with tamoxifen. Twenty-seven patients had positive estrogen receptor (ER+) status, and 23 negative estrogen receptor (ER-) status. Response was observed in 31 (62%) of the 50 analyzed patients (95% CI: 48.5-75.4%), with 5 complete responses (10%). A significantly better response rate was observed in ER+ patients (p = 0.03). The median duration of response was 16 months, and the median time to disease progression was 18 months. The median overall survival was 19 months (27 for responders and 7 for nonresponders). ER+ patients had a higher probability of survival (p = 0.02). Toxicity was moderate. Nausea/vomiting and myelotoxicity were the main side effects. In conclusion, MIMOC plus cyclical hormonotherapy represents a well-tolerated and effective first-line treatment for advanced breast cancer. The observed difference in response and survival in favor of ER+ patients warrants further investigation.