Evaluation of the Impact of Empty Versus Full Bladder in Patients With Prostate Cancer, RELIEF Trial

PRIMARY OBJECTIVE: I. To determine whether an empty bladder during radiation therapy delivery for prostate cancer is non-inferior to standard bladder filling for change in patient-reported urinary symptoms 3 months post-treatment. SECONDARY OBJECTIVES: I. To evaluate whether an empty bladder during radiation therapy delivery for prostate cancer is non-inferior to standard bladder filling for patient-reported bowel symptoms and patient-reported severity of urinary symptoms 3 months post-treatment. II. To compare physician-assessed genitourinary and gastrointestinal Common Terminology Criteria for Adverse Events (CTCAE) toxicity related to radiation therapy in patients treated with a full versus an empty bladder 3 months post-treatment. EXPLORATORY OBJECTIVES: I. To evaluate the differences in dosimetric parameters, using both absolute and relative volumetric measures, between the full bladder and empty bladder patients and correlate with toxicity scores 3 months post-treatment. II. To compare patient experience questionnaire answers between arms. III. To compare daily treatment evaluations by radiation therapists (RTT) between arms. IV. To test for moderation of the treatment effect on the primary endpoint by the four stratification factors. V. To evaluate whether an empty bladder during radiation therapy delivery for prostate cancer is non-inferior to standard bladder filling for patient-reported urinary symptoms at end of therapy (EOT) and severity, function, and bother 3 months post- treatment. OUTLINE: Patients are randomized to 1 of 2 arms. ARM I: Patients perform standard of care (SOC) bladder filling and then undergo computed tomography (CT) and radiation therapy in 2-39 fractions at the discretion of the treating clinician on study. ARM II: Patients perform bladder emptying and then undergo CT and radiation therapy in 2-39 fractions at the discretion of the treating clinician on study. After completion of study intervention, patients are followed up at 3 months.