Radiation Dose to the Penile Structures and Patient-Reported Sexual Dysfunction in Long-Term Prostate Cancer Survivors.

Abstract

The involvement of various penile structures in radiotherapy (RT)-induced sexual dysfunction among prostate cancer survivors remains unclear and domains beyond erectile dysfunction such as orgasm, and pain have typically not been considered. The purpose of this study was to investigate sexual dysfunction post-RT for localized prostate cancer and to examine whether radiation dose to different penile structures can explain these symptoms. We investigated sexual dysfunction in two treated prostate cancer cohorts and in one non-pelvic-irradiated cohort, 328 sexually active men part of an unselected, population-based study conducted in 2008. The treated subjects were prescribed primary/salvage external-beam RT to 70 Gy@2.0 Gy/fraction. Absorbed RT doses (Dmean and Dmax ) of the corpora cavernosa (CC), the penile bulb (PB), and the total penile structure (CC + PB) were related to 13 patient-reported symptoms on sexual dysfunction by means of factor analysis (FA) and logistic regression. Three distinct symptom domains were identified across all cohorts: "erectile dysfunction" (ED, two to five symptoms), "orgasmic dysfunction" (OD, two to four symptoms), and "pain" (two to three symptoms). The strongest predictor for ED symptoms was CC + PB Dmax (P = 0.001-0.03), CC and PB Dmean predicted OD symptoms equally well (P = 0.03 and 0.02-0.05, respectively), and the strongest predictor for pain symptoms was CC + PB Dmean (P = 0.02-0.03). Sexual dysfunction following RT was separated into three main domains with symptoms related to erectile dysfunction, orgasmic dysfunction, and pain. Chances for intact sexual functionality may be increased if dose to the total penile structure can be restricted for these domains in the planning of RT .