Renal toxicity in children undergoing total body irradiation for bone marrow transplant

Contribution of total body irradiation (TBI) to renal toxicity in children undergoing the bone marrow transplant (BMT) remains controversial. We report our institutional retrospective study that evaluates the frequency of acute and chronic renal dysfunction in children after using total body irradiation (TBI) conditioning regimens.

Between 1995 and 2003, 60 children with hematological malignancies underwent TBI as part of a conditioning regimen before allogeneic BMT. Patients received 4-14Gy at 1.75-2Gy/fraction in six-eight fractions. Lung shielding was used in all patients to limit lung dose to less than 10Gy; renal shielding was not utilized. All patients had baseline renal function assessment and renal dysfunction post-BM was mainly evaluated on the basis of persistent serum creatinine elevation at acute (0-90 days) and chronic (>90 days) intervals after completion of BMT.

Acute renal dysfunction (ARD) was documented in 27 patients (45%); the majority had concurrent diagnosis of veno-occlusive disease (VOD) or graft-versus-host disease (GVHD) and other potential causes (sepsis, antibiotic). The risk for delayed renal dysfunction (DRD) at 1 year approached 25% for surviving patients. The ARD was strongly linked with the risk of the DRD. There was no statistically significant relationship between ARD, DRD and underlying diagnosis, GVHD, VOD or TBI doses with both univariate and multivariate analyses. The younger age (<5 years) had significantly increased risk for the development of ARD (p=0.011).

Our analysis validates high incidence of renal dysfunction in the pediatric BMT population. In contrast to other reports we did not find total body irradiation dose to be a risk factor for renal dysfunction. Future prospective studies are needed to assess risk factors and interventions for this serious toxicity in children following allogeneic BM.