Patient-reported sexual toxicity after radiation therapy in long-term prostate cancer survivors
BACKGROUND This study sought to evaluate patient-reported health-related quality of life following proton therapy for prostate cancer in men ≤ 60 years old. METHODS Between August 2006 and January 2010, 262 hormone-naive men ≤ 60 years old were treated with definitive proton therapy for prostate cancer. Before treatment and every 6 months after treatment, patients filled out the Expanded Prostate Index Composite (EPIC) and the International Index of Erectile Function (IIEF) questionnaires. Potency was defined as successful sexual intercourse in the prior month or an EPIC sexual summary (SS) score ≥ 60. RESULTS Median follow-up was 24 months; 90% of men completed follow-up EPIC forms within the last year. For EPIC urinary, bowel, and hormone subscales, the average decline from baseline to 2 years was ≤5 points, except for bowel function (5.2 points). SS scores declined 12.6 points after 2 years. Potency rates declined by 11% from baseline at 2 years, but 94% of men were potent with a baseline IIEF > 21, body mass index < 30, and no history of diabetes. At 2 years after treatment, only 1.8% of men required a pad for urge incontinence. On multivariate analysis, factors associated with a significant decline in SS score were mean penile bulb dose ≥40 cobalt Gy equivalents (P = .012) and radiation dose ≥ 80 cobalt Gy equivalents (P = .017); only diabetes was significantly associated with impotence (P = .015). CONCLUSIONS Young men undergoing proton therapy for treatment of prostate cancer have excellent outcomes with respect to erectile dysfunction, urinary incontinence, and other health-related quality of life parameters during the first 2 years after treatment. Longer follow-up is needed to confirm these findings.