Tumor lysis syndrome (TLS) describes biochemical and clinical abnormalities resulting from spontaneous or treatment-induced necrosis of rapidly proliferating tumors such as Burkitt's lymphoma (BL). TLS can lead to complications like acute kidney injury (AKI) which can be fatal. In patients who had AKI in childhood, the frequency of kidney problems increases in later ages. Therefore, there is a need to examine long term kidney functions in patients with TLS. The purpose of our study is to investigate the laboratory and clinical features of tumor lysis syndrome in childhood non-Hodgkin lymphomas (NHL) and to reveal its impact on long term kidney function in survivors.

Our study was a single center retrospective study. 107 patients (0-18 years of age) admitted to our hospital between 1998-2020 years with a diagnosis of NHL and who received chemotherapy were included in the study. Clinical and laboratory characteristics of the patients at the time of diagnosis and within 14 days from the start of chemotherapy were examined. The presence of TLS and its laboratory and clinical features were examined according to the Cairo-Bishop criteria. The relationship between TLS and age, gender, histopathological subgroup, tumor stage, lactate dehydrogenase (LDH) level at presentation, bone marrow and kidney involvement were investigated. The presence of AKI was determined according to the Kidney Disease: Improving Global outcomes criteria. Long-term renal functions of the patients were investigated.

80.3% of the patients with a median age of 9.8 years were male. The most common histopathological subgroup was BL (77.5%), while the majority of patients (76.7%) had advanced disease. Clinical TLS (CTLS) was observed in 12.1% of the cases, and isolated laboratory TLS (LTLS) was observed in 18.7%. Hyperhydration±alkalinization and allopurinol were used in first-line treatment and prophylaxis. A significant correlation was found between young age, advanced stage, high lactate dehydrogenase level at presentation and LTLS. Bone marrow involvement was found to be significantly higher in the group with CTLS. AKI was observed in 12.1% of the patients. Out of a total of 103 patients whose treatment was completed, 93 (90.3%) patients survived and 10 deaths were observed. No death due to TLS was observed. The mean survival time was 215.55±7.502 months. After an average of 6.9 years, when the glomerular filtration rate values of the patients at the first admission and at the last admission were compared, a mean decrease of 10 mL/min/1.73 m2 was detected. However, it was not found to be statistically significant.

In our study, lower age, advanced stage, high LDH level at presentation were found to be risk factors for TLS. Long-term renal function loss was not detected in the survivors, for whom early and careful prophylaxis/treatment approaches were applied for TLS. The survivors are still being followed up.