Incidence of and risk factors for kidney dysfunction in childhood cancer survivors

Background Although therapeutic advances have improved the life expectancy of children with cancer, the late complication of kidney dysfunction represents a challenge. We aimed to measure the cumulative incidence and identify risk factors for kidney dysfunction (eGFR < 90 mL/min/1.73 m ² ) in survivors of childhood cancer. Methods We studied children treated for cancer who survived for > 5 years. The cumulative incidence of kidney dysfunction was measured and risk factors were identified using the Kaplan–Meier method, the log-rank test, and Cox proportional hazards analysis. Results Eighty-four survivors, who were a median of 5.7 years old at the start of treatment, were studied for a median of 9.0 years. Nineteen, 12, 15, 4, 20, 14, and 34 patients were treated using cisplatin (CDDP), carboplatin, ifosfamide, nephrectomy, total-body irradiation, kidney irradiation (≥ 10 Gy), or hematopoietic stem cell transplantation, respectively; and 14 developed relapse/secondary cancer. During treatment, acute kidney injury developed in 57.5% of patients. The cumulative incidence of kidney dysfunction was 10.7% after 5 years and 21.8% after 10 years. The log-rank test identified older age (≥ 5 years) at the initiation of treatment, solid tumor, CDDP therapy, ifosfamide therapy, and nephrectomy as significant risk factors; and a Cox proportional hazards model showed that older age (HR 3.89, p  = 0.033), CDDP therapy (HR 8.80, p  < 0.001), and nephrectomy (HR 10.20, p  = 0.016) were significant risk factors. Conclusions The long-term monitoring of kidney function is important for survivors of childhood cancer who received their initial treatment when relatively old, underwent CDDP-based chemotherapy, or underwent nephrectomy.