Delayed renal dysfunction after total body irradiation in pediatric malignancies

Abstract

The purpose of this study was to retrospectively evaluate the incidence of delayed renal dysfunction after total body irradiation (TBI) in long-term survivors of TBI/hematopoietic stem cell transplantation (HSCT). Between 1989 and 2006, 24 pediatric patients underwent TBI as part of the conditioning regimen for HSCT at Chiba University Hospital. Nine patients who survived for more than 5 years were enrolled in this study. No patient had any evidence of renal dysfunction prior to the transplant according to their baseline creatinine levels. The median age at the time of diagnosis was 6 years old (range: 1-17 years old). The follow-up period ranged from 79-170 months (median: 140 months). Renal dysfunction was assessed using the estimated glomerular filtration rate (eGFR). The TBI dose ranged from 8-12 Gy delivered in 3-6 fractions over 2-3 d. The patients were treated with linear accelerators in the supine position, and the radiation was delivered to isocentric right-left and left-right fields via the extended distance technique. The kidneys and the liver were not shielded except in one patient with a left adrenal neuroblastoma. No patient required hemodialysis. The eGFR of four patients (44.4%) progressively decreased. The remaining patients did not demonstrate any eGFR deterioration. Only one patient developed hypertension. By evaluating the changes in eGFR, renal dysfunction among long-term survivors of TBI/HSCT could be detected. Our results suggested that the TBI schedule of 12 Gy in 6 fractions over three consecutive days affects renal function.

Keywords: long-term survivor; pediatrics; renal toxicity; total body irradiation.

Fig. 1.

This graph shows the deterioration of eGFR in Patients (Pts) 2, 4, 6 and 7, who each received 12 Gy. The patients' eGFR progressively decreased.

Fig. 2.

This graph shows the variation in eGFR over time in Pts 1, 3, 5 and 9, who received 8 Gy, 10 Gy, 12 Gy and 12 Gy, respectively. Five of the nine patients did not suffer any eGFR deterioration.

Fig. 3.

This graph shows the variation in eGFR over time in Pt. 8, in whom hypertension subsequently developed. The patient's eGFR was 80–100 ml/min/1.73 m² and did not decline.