Among men undergoing radiation therapy for prostate cancer, daily use of the erectile dysfunction drug tadalafil did not prevent loss of erectile function when compared with placebo, according to a study.
Erectile dysfunction is a common condition resulting from many causes, including prostate cancer treatment, according to background information in the study, which was published in the April 2 issue of the Journal of the American Medical Association. An estimated 40% of men report erectile dysfunction after radiation therapy, and half of all men use erectile aids following this therapy. Tadalafil is used to treat erectile dysfunction after prostate cancer treatment, but its role as a preventive agent has not been determined.
Thomas M. Pisansky, MD, of the Mayo Clinic, Rochester, Minn., and colleagues with the Radiation Therapy Oncology Group randomly assigned 242 men with prostate cancer to receive tadalafil (5 mg) or placebo daily for 24 weeks starting with external radiotherapy or brachytherapy. The study was conducted at 76 sites in the U.S. and Canada, with participants recruited between November 2009 and February 2012 and followed-up through March 2013.
Between weeks 28 and 30 after the start of radiation therapy, among evaluable participants, 79% who received tadalafil retained erectile function compared with 74% who received placebo. A significant difference between groups was also not observed a year after the start of therapy (72% vs. 71%). Tadalafil was not associated with improved overall sexual function or satisfaction, and partners of men assigned tadalafil noted no significant effect on sexual satisfaction.
These findings do not support the scheduled once-daily use of tadalafil to prevent ED in men undergoing radiotherapy for localized prostate cancer, the authors wrote.
They add that alternative strategies to prevent ED in this context appear warranted, including different dosing or further refinements of radiation therapy delivery methods.
Study abstract: http://jama.jamanetwork.com/article.aspx?articleid=1853160