Prospective Evaluation of Renal Function Parameters in Children with Newly Diagnosed Acute Lymphoblastic Leukemia: A Cross-Sectional Study

Abstract Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy. Although survival outcomes have improved, renal impairment remains a clinically significant yet underrecognized complication. This study aimed to evaluate early renal function changes in children with ALL from diagnosis through remission induction. In this prospective cohort study, 60 children aged 1 to 12 years with newly diagnosed ALL were enrolled at a tertiary care center in India between October 2019 and March 2021. Renal function was assessed at baseline and 3 months postinduction using serum and urinary biomarkers, including creatinine, phosphate, potassium, uric acid, fractional excretion of sodium (FeNa%), and spot calcium/creatinine ratios. Tumor lysis syndrome (TLS) diagnosis was based on modified Cairo–Bishop criteria. Data were analyzed across age groups, immunophenotypes, and risk stratification categories. Thirteen patients met the TLS criteria at diagnosis, and showed significant improvement in serum biochemistry (p-value < 0.0001) by 3 months. Although serum creatinine remained within normal limits, significant declines were observed in serum phosphate (p < 0.001), potassium (p = 0.001), uric acid (p = 0.018), and FeNa% (p = 0.002), indicating subclinical renal stress. Urinary markers, including creatinine (p = 0.005) and calcium/creatinine ratio (p < 0.001), also changed significantly. T-cell ALL and high-risk patients exhibited more pronounced derangements, consistent with higher tumor burden and greater risk of TLS. Ultrasonography remained largely unremarkable. Biochemical and urinary changes are evident early in children with newly diagnosed ALL even when conventional renal function is normal, pointing out to the possibility of renal stress or change in tubular function especially in high-risk and T-cell ALL. Early biochemical surveillance, including urinary indices, is crucial for timely intervention and nephroprotection. These findings are particularly relevant in low-resource settings, where renal sequelae may go unrecognized.