Analysis of Clinical and Dosimetric Factors Associated With Change in Renal Function in Patients With Gastrointestinal Malignancies After Chemoradiation to the Abdomen

Purpose: To analyze clinical and dosimetric factors associated with change in renal function in patients with gastrointestinal malignancies after chemoradiation to the abdomen. Methods and Materials: A retrospective review of 164 patients with gastrointestinal malignancies treated between 2002 and 2007 was conducted to evaluate change in renal function after concurrent chemotherapy and three-dimensional conformal abdominal radiotherapy (RT). Laboratory and biochemical endpoints were determined before RT and after RT at 6-month intervals. Factors assessed included smoking, diabetes, hypertension, blood urea nitrogen, creatinine, creatinine clearance (CrCl), chemotherapy, and dose-volume parameters. Renal toxicity was assessed by decrease in CrCl and scored using the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer late radiation morbidity scoring schema. Results: Of 164 patients, 63 had clinical and dosimetric data available. Median follow-up was 17.5 months. Creatinine clearance declined from 98.46 mL/min before RT to 74.20 mL/min one year after chemoradiation (p < 0.0001). Mean decrease in CrCl was 21.37%. Pre-RT CrCl, percentage of bilateral renal volume receiving at least 10 Gy (V10), and mean kidney dose were significantly associated with development of Grade ≥2 renal complications at 1 year after chemoradiation (p = 0.0025, 0.0170, and 0.0095, respectively). Conclusions: We observed correlation between pre-RT CrCl, V10, and mean kidney dose and decline in CrCl 1 year after chemoradiation. These observations can assist in treatment planning and renal dose constraints in patients receiving chemotherapy and abdominal RT and may help identify patients at increased risk for renal complications.