[Favorable effect of sildenafil on erectile dysfunction in patients after radiotherapy for prostate cancer; randomised, double-blind, placebo-controlled crossover study].

Objective. To determine the efficacy of sildenafil in patients with erectile dysfunction after external beam radiotherapy for prostate cancer. Design. Randomised, double-blind, placebo-controlled, cross-over study. Method. A total of 406 patients with erectile dysfunction reported in their medical records who had completed external beam radiotherapy at least 6 months prior to the study, were approached by letter. Sixty patients were included in a study which lasted 12 weeks. They received 50 mg of sildenafil citrate or placebo for two weeks; during week 2 the dose could be increased to I00 mg in the case of unsatisfactory erectile response. At week 6 patients crossed over to the alternative treatment. Data were collected using the validated 'International index of erectile function' (IIEF) questionnaire, and side-effects were recorded. Patients were given the possibility of continuing to a 6-week open-label phase. Results. The mean age of those participating was 68 years. All patients completed the double-blind phase. For the majority of questions in the IIEF questionnaire, there was a significant increase in mean scores from baseline with sildenafil, but not with placebo. Successful intercourse was reported by 55% of the patients with sildenafil, versus 18% with placebo. Ninety per cent of the patients required a dose adjustment to too mg sildenafil, and I00% of the patients in the placebo group increased the dose. Side-effects were mild or moderate. Patients who proceeded to the open-label phase reported the same results as in the double-blind phase. Conclusion. Sildenafil improved erectile function in about half of the patients with erectile dysfunction after external beam radiotherapy for prostate cancer, and it was well tolerated.