October 31, 2012 — Sildenafil citrate (SC), a phosphodiesterase type 5 inhibitor, administered before, during and after radiation therapy improved overall sexual function of prostate cancer patients, according to research presented at the American Society for Radiation Oncology’s (ASTRO’s) 54th Annual Meeting.
This is the first prospective, randomized, double-blind, placebo controlled trial to determine if daily, adjuvant use of SC before, during and after radiation therapy preserves erectile function in prostate cancer patients. The study included 290 patients with clinically localized prostate cancer who were treated with external beam radiation therapy and/or permanent interstitial implantation and were randomly assigned to two groups (2:1 randomization): those who received a 50 mg dose daily of SC, and those who received a placebo.
Patients in both groups were asked to complete the international index of erectile function (IIEF) and international prostate symptom score (IPSS) questionnaires before therapy and at six, 12 and 24 months after radiation treatment. Results from 144 patients, those who completed the surveys before therapy and at least one additional time period, indicate that those in the SC group experienced improved overall sexual function compared to the placebo group at all time points, accounting for IIEF scores of 58.6 vs. 49.4, 56.3 vs. 48.2 and 54.9 vs. 47.6, respectively. Patient characteristics including age, use of brachytherapy, androgen deprivation therapy and baseline IIEF scores were similar in both treatment groups.
Patients received medication three days before their radiation treatment and continued with a daily dose for six months, after which daily use of SC or the placebo was discontinued and taken on an as-needed basis only. IIEF scores were based on patient feedback about their erectile function, orgasmic function, sexual desire, intercourse satisfaction and overall satisfaction.
“Our study found that prostate cancer patients treated with sildenafil citrate and adjuvant radiation treatment had improved overall erectile function and overall satisfaction of their sexual activity and function,” said Michael J. Zelefsky, M.D., lead author of the study and a radiation oncologist at Memorial Sloan-Kettering Cancer Center in New York. “The most significant improvements were seen at six and 12 months following treatment, with a slight dip at the 24-month mark, suggesting that future trials need to be conducted to demonstrate if a longer treatment duration can further improve patient outcomes.”
The abstract, “Results of a Prospective Randomized Double-blind Placebo Controlled Trial Evaluating the Use Prophylactic Sildenafil Citrate During Radiation Therapy in the Treatment of Prostate Cancer,” was presented in detail during a scientific session at ASTRO’s 54th Annual Meeting on Monday, Oct. 29, 2012.
For more information: www.astro.org
November 13, 2025 
