A RISK MODEL FOR THROMBOCYTOPENIA REQUIRING PLATELET TRANSFUSION AFTER CYTOTOXIC CHEMOTHERAPY

Severe thrombocytopenia is a rare but life-threatening side effect of cytotoxic chemotherapy for which risk factors are not well known. Our objective was to delineate a risk model for chemotherapy-induced throm bocytopenia requiring platelet transfusions in cancer patients. Univar iate and multivariate analysis of risk factors for chemotherapy-induce d thrombocytopenia requiring platelet transfusions were performed on t he cohort of the 1,051 patients (CLB 1996) treated with chemotherapy i n the Department of Medicine of the Centre Leon Berard (CLB) in 1996. In univariate analysis, performance status (PS) greater than 1, platel et count less than 150,000/mu L at day 1 (dl) before the initiation of chemotherapy, dl lymphocyte count less than or equal to 700/mu L, dl polymorphonuclear leukocyte count less than 1,500/mu L, and the type o f chemotherapy (high risk v others) were significantly associated (P < .01) with an increased risk of severe thrombocytopenia requiring plate let transfusions. Using logistic regression, dl platelet count less th an 150,000/mu L (odds ratio [OR], 4.3; 95% confidence interval [CI], 1 .9 to 9.6), dl lymphocyte counts less than or equal to 700/1 mu L (OR, 3.37; 95% CI, 1.77 to 6.4), the type of chemotherapy (OR, 3.38; 95% C I, 1.77 to 6.4), and PS greater than 1 (OR, 2.23; 95% CI, 1.22 to 4.1) were identified as independent risk factors for platelet transfusions . The observed incidences of platelet transfusions were 45%, 13%, 7%, and 1.5% for patients with greater than or equal to 3, 2, 1, or 0 risk factors, respectively. This model was then tested in 3 groups of pati ents treated with chemotherapy used as validation samples: (1) the ser ies of 340 patients treated in the CLB in the first 6 months of 1997, (2) the prospective multicentric cohort of 321 patients of the ELYPSE 1 study, and (3) the series of 149 patients with non-Hodgkin's lymphom a treated in the CLB within prospective phase III trials (1987 to 1995 ). In these 3 groups, the observed incidences of platelet transfusions in the above-defined risk groups did not differ significantly (P >.1) from those calculated in the model. This risk index could be useful to identify patients at high risk for chemotherapy-induced thrombocytope nia requiring platelet transfusions. (C) 1998 by The American Society of Hematology.