Erectile function preservation after radiotherapy using a dose-optimization approach on sexual structures for localized prostate cancer

Abstract

Purpose: Erectile function preservation is an important quality of life factor in patients treated for prostate cancer. A dose-optimization approach on sexual structures was developed and evaluated to limit erectile dysfunction after radiotherapy.

Materials and methods: Twenty-three men with localized prostate cancer and no erectile dysfunction were enrolled in the study. All patients received a prescription dose between 76 and 78Gy. Computed tomography/magnetic resonance image registration was used to delineate the prostatic volume and the sexual structures: internal pudendal arteries (IPA), penile bulb and corpus cavernosum. Erectile function was evaluated using the 5-items International Index of Erectile Function (IIEF-5) score every 6 months during the 2 years after radiotherapy and once a year afterwards. No erectile dysfunction, mild erectile dysfunction and severe erectile dysfunction were defined if the IIEF-5 scores were 20-25, 17-19 and < 17, respectively.

Results: The mean follow-up was 4.5 years. The mean age of the patients was 66.3 years. At 2 years, 67% of the patients had no erectile dysfunction, 11% had mild erectile dysfunction and 22% had severe erectile dysfunction. No significant difference was found between the patients with and without erectile dysfunction (IIEF-5≥20 and IIEF-5<20, respectively) for any of the parameters: dosimetric values (internal pudendal arteries, penile bulb, corpus cavernosum), age, comorbidity and smoking status. The biochemical-relapse free survival was 100% at 2 years.

Conclusion: This approach with dose-optimization on sexual structures for localized prostate cancer found excellent results on erectile function preservation after radiotherapy, with 78% of the patients with no or mild erectile dysfunction at 2 years.

Keywords: Cancer; Dose; Dose optimization; Erectile function; Fonction érectile; IRM; Magnetic resonance imaging; Optimisation; Prostate; Prostate cancer; Radiotherapy; Radiothérapie; Sexual structures; Structures sexuelles.