Sexual quality of life following prostate intensity modulated radiation therapy (IMRT) with a rectal/prostate spacer: Secondary analysis of a phase 3 trial

Daniel A. Hamstra, Beaumont Hospital
Neil Mariados, Associated Medical Professionals of NY
John Sylvester, 21st Century Oncology, Inc.
Dhiren Shah, Western New York Urology Associates, LLC /D/B/A Cancer Care of WNY
Eric Gross, The Urology Center of Colorado
Richard Hudes, Chesapeake Urology Associates d/b/a Chesapeake Urology Research Associates (The Prostate Center)
David Beyer, Cancer Centers of Northern Arizona Healthcare
Steven Kurtzman, Urological Surgeons of Northern California Inc.
Jeffrey Bogart, SUNY Upstate Medical University
R. Alex Hsi, Peninsula Cancer Center
Michael Kos, Northern Nevada Radiation Oncology
Rodney Ellis, University Hospitals Case Medical Center
Mark Logsdon, Sutter Health Sacramento Sierra Region
Shawn Zimberg, Advanced Radiation Centers of New York
Kevin Forsythe, Oregon Urology Institute
Hong Zhang, University of Rochester
Edward Soffen, CentraState Medical Center
Patrick Francke, 21st Century Oncology, Inc.
Constantine Mantz, 21st Century Oncology, Inc.
Peter Rossi, Emory University
Theodore DeWeese, Johns Hopkins University
Stephanie Daignault-Newton, University of Michigan, Ann Arbor
Benjamin W. Fischer-Valuck, Washington University School of Medicine in St. Louis
Anupama Chundury, Washington University School of Medicine in St. Louis
Hiram A. Gay, Washington University School of Medicine in St. Louis
Walter Bosch, Washington University School of Medicine in St. Louis
Jeff Michalski, Washington University School of Medicine in St. Louis

Abstract

© 2017 The Authors Background We previously reported the results of a phase 3 trial evaluating a prostate/rectal hydrogel spacer during prostate intensity modulated radiation therapy, which resulted in decreased rectal dose and toxicity and less decline in bowel quality of life (QOL). A secondary analysis was performed to correlate penile bulb dose and sexual QOL. Methods and materials Sexual QOL was measured with the Expanded Prostate Cancer Index Composite (EPIC) by mean scores, the proportion of patients with a minimal clinically important difference (MID), and analyses of the different items composing the sexual domain. Results A total of 222 men enrolled with median follow-up of 37 months. Hydrogel reduced penile bulb mean dose, maximum dose, and percentage of penile bulb receiving 10 to 30 Gy (all P <.05) with mean dose indirectly correlated with erections sufficient for intercourse at 15 months (P =.03). Baseline EPIC was low (53 [standard deviation ± 24]) with no difference between arms (P >.1). A total of 41% (88/222) of men had adequate baseline sexual QOL (EPIC >60 (mean, 77 [± 8.3]). This subgroup at 3 years had better sexual function (P =.03) with a spacer with a smaller difference in sexual bother (P =.1), which resulted in a higher EPIC summary on the spacer arm (58 [±24.1] vs control 45 [± 24.4]) meeting threshold for MID without statistical significance (P =.07). There were statistically nonsignificant differences favoring spacer for the proportion of men with MID and 2× MID declines in sexual QOL with 53% vs 75% having an 11-point decline (P =.064) and 41% vs 60% with a 22-point decline (P =.11). At 3 years, more men potent at baseline and treated with spacer had “erections sufficient for intercourse" (control 37.5% vs spacer 66.7%, P =.046) as well as statistically higher scores on 7 of 13 items in the sexual domain (all P <.05). Conclusions The use of a hydrogel spacer decreased dose to the penile bulb, which was associated with improved erectile function compared with the control group based on patient-reported sexual QOL.