Tumor lysis syndrome in pediatric patients with hematological malignancies

BACKGROUND: Tumor lysis syndrome (TLS) is a common complication of hematological malignancies and consists of either hyperkalemia, hyperphosphatemia, hyperuricemia, or hypocalcemia. These metabolic derangements may result in clinical tumor lysis syndrome in the form of acute kidney injury (AKI), arrhythmias, seizures, and sudden death. OBJECTIVES: This study was conducted to determine the incidence and outcome of TLS and to identify local risk factors in children with hematological malignancies. PATIENTS AND METHODS: This was a retrospective chart review of children ≤18 years diagnosed with acute lymphoblastic leukemia (ALL), acute myeloid leukemia, or non-Hodgkin lymphoma between 2014 and 2018. TLS was diagnosed and stratified according to the risk of developing tumor lysis using the Cairo and Bishop definition and Cairo stratification. RESULTS: Among 180 patients, only 11 patients (6%) developed TLS. Four patients had laboratory TLS (LTLS) (36.3%) and six had CLTS (54.5%). The male-to-female ratio was high (2.4:1 in the TLS group). Hyperphosphatemia and hypocalcemia were the most frequently occurring criteria for LTLS (81.8%). The strongest predictors for TLS were hyperuricemia and hypocalcemia at presentation (P < 0.001) followed by diagnosis of T-cell ALL, preceding AKI splenomegaly, high initial white blood cell, and lactate dehydrogenase, with P < 0.05. AKI secondary to tumor lysis occurred in six patients (54.5%), of which five needed dialysis. One patient had seizures secondary to tumor lysis (9.1%) and no patient died from TLS. CONCLUSION: There is a wide variation in reported incidence of TLS from 6% to 45%, likely due to different TLS definitions applied, diverse cohorts and duration. A universal definition and risk-stratified approach to prevent tumor lysis in patients with hematologic malignancies is needed to help in proper comparison between studies.