ABSTRACT
PURPOSE: Occurrence of genitourinary (GU) toxicity is a common adverse event observed after external beam radiotherapy (EBRT) for prostate cancer (PCa). Recent findings suggest that the dose delivered to specific urinary organs-at-risk (OARs) such as ureters, bladder trigone, and urethra is involved in the development of GU toxicity. METHODS AND MATERIALS: A multidisciplinary task force including three radiation oncologists, a uroradiologist, and a urologist was created in 2022. First, OARs potentially involved in GU toxicity were identified and discussed. A literature review was performed, addressing several questions relative to urinary OARs: anatomical and radiological definition, radiation-induced injury, dose-volume parameters. Secondly, results were presented and discussed with a panel of radiation oncologists, members of the "Francophone Group of Urological Radiation Therapy" (GFRU). Thereafter, GFRU experts were asked to answer a dedicated questionnaire, including 35 questions on the controversial issues related to the delineation of urinary OARs. RESULTS: The following structures were identified as critical for PCa EBRT: ureters, bladder, bladder neck, bladder trigone, urethra (intraprostatic, membranous, spongious), striated sphincter, and post-enucleation or post-transurethral resection of the prostate (TURP) cavity. A consensus was obtained for 32 out of 35 items. CONCLUSION: This consensus highlights contemporary urinary structures in both upper and lower urinary tract to be considered for EBRT treatment planning of PCa. The current recommendations also propose a standardized definition of urinary OARs, for both daily practice and future clinical trials.
