Tumor lysis syndrome in patients with acute myeloid leukemia: identification of risk factors and development of a predictive model.

BACKGROUND Despite the prophylactic use of allopurinol, tumor lysis syndrome (TLS)-related morbidity and mortality still occur in a number of patients with acute myeloid leukemia (AML). The aim of this study was: (i) to analyze the incidence and outcome of TLS in a large series of patients with AML receiving hyperhydration and allopurinol, (ii) to identify risk factors for TLS, and (iii) to develop a prognostic scoring system for estimating individual risk of TLS. DESIGN AND METHODS The study included 772 adult patients with AML receiving induction chemotherapy between 1980 and 2002. TLS was divided into laboratory TLS (LTLS) or clinical TLS (CTLS). The population study was randomly divided into training and test subsets, so that a prognostic model for CTLS was developed in one set and validated in the other. RESULTS Overall, 130 patients (17%) developed TLS (5% CTLS and 12% LTLS). Unlike LTLS, CTLS was associated with a higher rate of death from induction therapy. Multivariate analysis showed that pretreatment serum lactate dehydrogenase (LDH) levels above laboratory normal values, creatinine >1.4 mg/dL, uric acid >7.5 mg/dL and white blood cell (WBC) counts >25 x 10(9)/L were independent risk factors for CTLS and LTLS. The scoring system, based on pretreatment WBC counts, and uric acid and LDH serum levels, had excellent discrimination and was accurate for predicting CTLS and LTLS. CONCLUSIONS TLS is frequently observed in AML patients during induction therapy. Only the development of CTLS had an impact on higher mortality rate from induction therapy. The scoring system derived from this study can be used to obtain an accurate estimate of the individual risk of TLS, allowing for risk-adapted prophylaxis against this complication.