A RANDOMIZED CROSSOVER TRIAL OF TAMOXIFEN VERSUS OVARIAN ABLATION FORMETASTATIC BREAST-CANCER IN PREMENOPAUSAL WOMEN - A REPORT OF THE NATIONAL-CANCER-INSTITUTE OF CANADA CLINICAL-TRIALS GROUP (NCIC CTG) TRIAL MA.1

We concluded a randomized crossover trial comparing tamoxifen 40 mg da ily with ovarian ablation for treatment of metastatic breast cancer in premenopausal women. Objective responses (complete response (CR) plus partial response (PR)) were observed in 5/20 patients treated initial ly with tamoxifen and in 3/19 patients initially treated with ovarian ablation (p = 0.69). Seven additional patients were stable (SD) on tam oxifen while five additional patients were stable after ovarian ablati on, for CR + PR + SD rates of 12/20 (60%) for tamoxifen and 8/19 (42%) for ovarian ablation (p 0.34). Median time to disease progression was 184 days for tamoxifen and 126 days for ovarian ablation (p = 0.40, l ogrank test, odds ratio for progression 0.71). Overall survival times were also similar: a median of 2.35 years for tamoxifen and 2.36 years for ovarian ablation (p = 0.98, logrank test, odds ratio for death 1. 07). Side effects from tamoxifen included hot flashes and menstrual ab normalities. With one exception? these toxicities were not sufficient to require dose reduction. In this small study, tamoxifen was associat ed with similar response rates, response durations, and survival times to those observed with ovarian ablation.