Preliminary patient-reported outcomes analysis of 3-dimensional radiation therapy versus intensity-modulated radiation therapy on the high-dose arm of the Radiation Therapy Oncology Group (RTOG) 0126 prostate cancer trial

BACKGROUND The authors analyzed a preliminary report of patient-reported outcomes (PROs) among men who received high-dose radiation therapy (RT) on Radiation Therapy Oncology Group study 0126 (a phase 3 dose-escalation trial) with either 3-dimensional conformal RT (3D-CRT) or intensity-modulated RT (IMRT). METHODS Patients in the 3D-CRT group received 55.8 gray (Gy) to the prostate and proximal seminal vesicles and were allowed an optional field reduction; then, they received 23.4 Gy to the prostate only. Patients in the IMRT group received 79.2 Gy to the prostate and proximal seminal vesicles. PROs were assessed at 0 months (baseline), 3 months, 6 months, 12 months, and 24 months and included bladder and bowel function assessed with the Functional Alterations due to Changes in Elimination (FACE) instrument and erectile function assessed with the International Index of Erectile Function (IIEF). Analyses included the patients who completed all data at baseline and for at least 1 follow-up assessment, and the results were compared with an imputed data set. RESULTS Of 763 patients who were randomized to the 79.2-Gy arm, 551 patients and 595 patients who responded to the FACE instrument and 505 patients and 577 patients who responded to the IIEF were included in the completed and imputed analyses, respectively. There were no significant differences between modalities for any of the FACE or IIEF subscale scores or total scores at any time point for either the completed data set or the imputed data set. CONCLUSIONS Despite significant reductions in dose and volume to normal structures using IMRT, this robust analysis of 3D-CRT and IMRT demonstrated no difference in patient-reported bowel, bladder, or sexual functions for similar doses delivered to the prostate and proximal seminal vesicles with IMRT compared with 3D-CRT delivered either to the prostate and proximal seminal vesicles or to the prostate alone. Cancer 2015;121:2422-2430.