['To determine the effects of anemia on local relapse-free, relapse-free, and overall survival (LRFS, RFS, and OS, respectively) in premenopausal, primary breast cancer patients receiving adjuvant polychemotherapy, and to determine which conventional prognostic factors affected these outcomes.', 'Four hundred twenty-four premenopausal patients with early-stage primary breast cancer and hormone receptor-expressing tumors were treated with i.v. cyclophosphamide/methotrexate/5-fluorouracil (CMF) polychemotherapy as part of an adjuvant phase III trial (Austrian Breast and Colorectal Cancer Study Group Trial 5). The influence of anemia (hemoglobin <12 g/dL) on LRFS, RFS, and OS was evaluated in a retrospective analysis.', 'Of 424 patients, 77 (18.2%) developed anemia on CMF chemotherapy. After a median follow-up time of 5 years, 8.9% of nonanemic patients had local relapse compared with 19.6% of anemic patients (P=0.0006). Although mastectomy was associated with anemia (26% versus 13.7% in breast conserving surgery; P=0.002), multivariate analysis did not show mastectomy per se to be a significant risk factor for LRFS. Age, lymph node status, and hemoglobin had an independent significant influence on LRFS (P<0.005). Anemic patients had a relative risk of 2.96 (95% confidence interval, 1.41-6.23) for developing local relapse in comparison with nonanemic patients.'] Is anemia a significant prognostic factor in local relapse-free survival of premenopausal primary breast cancer patients receiving adjuvant cyclophosphamide/methotrexate/5-fluorouracil chemotherapy?