After initial surgery, 240 pre-, peri- or postmenopausal patients with early node-negative breast carcinoma were randomized to receive either no hormone therapy or adjuvant therapy with medroxyprogesterone acetate at high dosage (HD-MPA; 500 mg IM per day times 28 or 500 mg intramuscularly (i.m.) 5 days a week for 5 weeks then 500 mg i.m. twice weekly for the 5 following months. After a median follow-up time of 3 years, relapse-free survival and overall survival appeared significantly improved in the HD-MPA arm. Side effects were tolerable.