Kidney Function and Body Composition in Adult Survivors of Unilateral, Non-Syndromic Wilms Tumor: A Report From the St. Jude Lifetime Cohort Study

Background: The relationships among treatment exposures, body composition, and estimated glomerular filtration rate (eGFR) in adult survivors of Wilms tumor have not been well studied. Methods: We evaluated body composition with dual-energy x-ray absorptiometry (DXA) and eGFR with the updated Chronic Kidney Disease Epidemiology Collaboration equations (creatinine only-eGFR(Cr), cystatin C only-eGFR(CysC), creatinine and cystatin C-eGFR(Cr+CysC)) without race in 134 adults previously treated for unilateral, non-syndromic Wilms tumor at St. Jude Children's Research Hospital between 1964 and 2004 with chemotherapy and with (hemiabdomen [HA] or whole abdomen [WA]) or without radiation therapy (RT). Z-scores for DXA variables were calculated using data from the National Health and Nutrition Examination Survey. Results: WART was associated with a lower relative total (p = 0.004) and trunk (p < 0.001) lean mass, eGFRCr (p = 0.008), eGFR(CysC), (p < 0.001), and eGFR(Cr+CysC )(p < 0.001), and higher values of cystatin C (p < 0.001). Linear regression demonstrated that relative total lean mass (p = 0.009) and relative trunk lean mass (p < 0.001) Z-scores, and eGFR(Cr) (p = 0.013) were lower among those who received WART compared to No RT patients. Conclusions: WART is associated with lower relative total and trunk lean mass Z-scores and eGFR, regardless of the equation used, and is lower in survivors treated with WART compared to unirradiated survivors of unilateral, non-syndromic WT. Assessments using other GFR measures may provide greater insight into the mechanism and magnitude of kidney function loss among WART-treated WT survivors.