Analysis of the Impact of Androgen Deprivation Therapy on Sildenafil Citrate Response Following Radiation Therapy for Prostate Cancer

Abstract

Radiation therapy is a widely accepted strategy for prostate cancer. Erectile dysfunction is a common complication of radiation therapy. Adjuvant androgen deprivation was shown to prolong survival in select patients. There is controversy regarding the impact of androgen deprivation on erectile function. We defined the impact of androgen deprivation on the sildenafil response in patients with erectile dysfunction following radiation therapy. Patients were enrolled prospectively if they underwent radiation therapy in the form of 3-dimensional conformal external beam or brachytherapy with or without androgen deprivation, reported functional erections before radiation therapy, experienced the onset of erectile dysfunction following the completion of radiation therapy, had comprehensive erectile dysfunction evaluation, including a thorough history and physical examination, attempted sildenafil periodically and completed the International Index of Erectile Function on at least 2 occasions throughout the first 3 years following the completion of radiation therapy. A total of 152 patients were enrolled. Mean age +/- SD was 62 +/- 14 years. No significant difference existed in age or radiation dose between patients with and without androgen deprivation exposure. Mean androgen deprivation duration was 3.8 +/- 1.8 months. For patients with conformal external beam and brachytherapy the sildenafil response, mean erectile function domain score and percent who experienced erectile function domain normalization at each time point were lower in those with vs without androgen deprivation. Androgen deprivation seems to exert a deleterious effect on erectile function in men undergoing radiation therapy for prostate cancer. This was observed in men treated with conformal external beam and brachytherapy at short-term, medium term and long-term followup.