Oral Metronomic Chemo-Hormonal-Therapy of Metastatic Breast Cancer with Cyclophosphamide and Megestrol Acetate

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.