[The chronological process of erectile function after low-dose rate prostate brachytherapy for localised prostate...

The aim of this study was to evaluate the effect of low-dose rate prostate (LDR) brachytherapy on erectile function in correlation to the time intervals after seed implantation.

32 patients with localised prostate cancer and a median age of 74 years (range 65-83) were treated with permanent seed implantation. Erectile function was assessed by means of a validated questionnaire (IIEF-5) before and at 12, 24 and 36 months after treatment. No patient received supplemental external beam -radiation therapy or antiandrogen therapy. Of the 32 patients, 26 (81%) completed and returned the questionnaire. None of the patients used PDE-5 inhibitors or intracavernousal injection therapy.

Before treatment, 15 patients (58%) had no erectile dysfunction (ED) (score 22-25) or mild ED (score 17-21), 11 (42%) moderate or -severe ED (score 0-16). Overall, before seed implantation the mean IIEF score was 14.4. The mean IIEF score decreased by 4.4 points 12 months after treatment, 3.1 points 24 months after treatment and 9.8 points 36 months after treatment (p < 0.05). In the group of no or mild ED, the mean IIEF score dropped by 9.7 points compared to a decrease of 1.4 points in the group of mod-erate or severe ED.

Most of the patients treated with LDR brachytherapy suffered an ED in correlation to the time interval with a significant loss in the third year after treatment. In this study, the most significant loss occured in the groups that had no or only mild erectile dysfunction before treatment.