Gunstig effect van sildenafil op erectiele disfunctie bij patiënten na radiotherapie voor prostaatkanker; gerandomiseerd, dubbelblind, placebogecontroleerd en gekruist onderzoek

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 100 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 100 mg sildenafil, and 100 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.