RESUMEN
Metronomic chemotherapy is an anticancer strategy which uses conventional cytotoxic drugs administered at very low dose in close intervals. We have designed a phase II trial to investigate the safety and antitumor activity of the newest metronomic chemo-hormonal-therapy with daily cyclophosphamide and twice daily megestrol acetate (mCM regimen) in patients with metastatic pretreated breast cancer.Twenty-nine pretreated post-menopausal patients with multiple metastatic sites were enrolled. four patients had a triple negative status, nineteen a positive hormonal ER and PgR status, and three ERB-B2 over-expression. Patients received treatment with cyclophosphamide (50 mg/daily day 1-21/q28) and fractionated megestrol acetate (80 mg twice a day). The overall objective response rate was 31.0%, disease control rate 41.3%, mean time to tumor progression 7.4 months (CI 95%, 3.8-10.88, range 1-48 months) and mean overall survival 13.4 months (CI 95%, 7.24-17.18, range 1-53 months). The mCM regimen was active and well tolerated.