Epoetin treatment of anemia associated with cancer therapy: A systematic review and meta-analysis of controlled clinical trials

Epoetin treatment offers an attractive but costly alternative to red blood cell transfusion for managing anemia associated with cancer therapy. The go al of this review is to facilitate more efficient use of epoetin by 1) quan tifying the effects of epoetin on the likelihood of transfusion and on qual ity of life in patients with cancer treatment-related anemia and 2) evaluat ing whether outcomes are superior when epoetin treatment is initiated at hi gher hemoglobin thresholds. Two independent reviewers followed a prospectiv e protocol for identifying studies. Outcomes data were combined with the us e of a random-effects meta-analysis model. Double-blind, randomized, contro lled trials that minimized patient exclusions were defined as higher qualit y for sensitivity analysis; randomized but unblinded trials and trials with excessive exclusions were included in the meta-analysis but were defined a s lower quality. Twenty-two trials (n = 1927) met inclusion criteria, and 1 2 (n = 1390) could be combined for estimation of odds of transfusion. Epoet in decreased the percentage of patients transfused by 9%-45% in adults with mean baseline hemoglobin concentrations of 10 g/dL or less (seven trials; n = 1080), by 7%-47% in those with hemoglobin concentrations greater than 1 0 g/dL but less than 12 g/dL (seven trials; n = 431), and by 7%-39% in thos e with hemoglobin concentrations of 12 g/dL or higher (five trials; n = 308 ). In sensitivity analysis, the combined odds ratio for transfusion in epoe tin-treated patients as compared with controls was 0.45 (95% confidence int erval [CI] = 0.33 to 0.62) in higher quality studies and 0.14 (95% CI = 0.0 6 to 0.31) in lower quality studies. ne number of patients needed to treat to prevent one transfusion is 4.4 for all studies, 5.2 for higher quality s tudies, and 2.6 for lower quality studies. Only studies with mean baseline hemoglobin concentrations of 10 g/dL or less reported statistically signifi cant effects of epoetin treatment on quality of life; quality-of-fife data were insufficient for meta-analysis. No studies addressed epoetin's effects on anemia-related symptoms. We conclude that epoetin reduces the odds of t ransfusion for cancer patients undergoing therapy. Evidence is insufficient to determine whether initiating epoetin earlier spares more patients from transfusion or results in better quality of life than waiting until hemoglo bin concentrations decline to nearly 10 g/dL.