Dose-volume histogram-based predictors for hematuria and rectal hemorrhage in patients receiving radiotherapy after radical prostatectomy

Abstract

Aim: The aim of this study was to evaluate the dose-volume histogram parameters for late hematuria and rectal hemorrhage in patients receiving radiotherapy after radical prostatectomy. Patients and Methods: Data of 86 patients treated between January 2006 and June 2019 were retrospectively evaluated. The median radiation dose was 64 Gy in 32 fractions. Receiver operating characteristic (ROC) curves were used to identify optimal cut-off values for late adverse events. Results: Eleven patients experienced hematuria, and the 5-year cumulative rate was 18%. Four patients experienced rectal hemorrhage, and the 5-year cumulative rate was 7%. ROC curve analysis demonstrated the following significant cutoff values: bladder V50 Gy: 43% (p=0.02) and V40 Gy: 50% (p=0.03) for hematuria, and rectum V60 Gy: 13% (p=0.04) and V50 Gy: 33% (p=0.03) for rectal hemorrhage. Conclusion: This is the first study to identify dose constraints that may reduce hematuria and rectal hemorrhage in patients receiving radiotherapy in the postoperative setting.