Preservation of organs related to future sexual function during prostate stereotactic body radiotherapy: feasibility analysis through a re-optimization process.

Preserving the quality of life and sexual function of patients with a localized prostate cancer remains a challenge for physicians and a major issue for patients. The present study aimed at demonstrating the feasibility of a dosimetric preservation of the sexual organs during prostate stereotactic radiotherapy planning. Patients from a single centre were retrospectively included in the RPAH-2 trial and randomized in Arm B if they presented with either a low- or intermediate- risk prostate cancer. A 37.5Gy in 5 fractions stereotactic body radiotherapy was delivered on the prostate gland. The corpus cavernosum, penile bulb and internal pudental arteries were retrospectively delineated before a re-optimization process. During this process, RPAH-2 trial dose constraints were respected on Gross Tumor Volume (GTV), Planning Target Volume and usual organs at risk. Pre-defined dose setting delivered to corpus cavernosum, penile bulb and internal pudental arteries were collected and compared before and after the re-optimization process. Nine patients were included in the study. A decrease of the median of each investigated dose setting (except D90% for corpus cavernosum) was reported after the re-optimization for corpus cavernosum, penile bulb and internal pudental arteries. Our study demonstrated the feasibility of a dosimetric preservation of structures considered as relevant to preserve sexual function after prostate stereotactic radiotherapy.