Testing Shorter Duration Radiation Therapy Versus the Usual Radiation Therapy in Patients With High Risk Prostate Cancer

This phase III trial compares stereotactic body radiation therapy (SBRT), (five treatments over two weeks using a higher dose per treatment) to usual radiation therapy (20 to 45 treatments over 4 to 9 weeks) for the treatment of high-risk prostate cancer. SBRT uses special equipment to position a patient and deliver radiation to tumors with high precision. This method may kill tumor cells with fewer doses over a shorter period of time. This trial is evaluating if shorter duration radiation prevents cancer from coming back as well as the usual radiation treatment.

PRIMARY OBJECTIVE:

1. To compare metastasis-free survival, determined using conventional imaging, between men with high-risk prostate cancer randomized to ultrahypofractionation (stereotactic body radiation therapy [SBRT]) to those randomized to moderate hypofractionation and conventional fractionation.

SECONDARY OBJECTIVES:

1. To compare physician-reported toxicity as measured by Common Terminology Criteria for Adverse Events (CTCAE) version (v)5 between treatment arms.

II. To determine if ultrahypofractionation is non-inferior to moderate hypofractionation and conventional fractionation with respect to patient-reported urinary function (assessed by Expanded Prostate Cancer Index Composite [EPIC]-26 urinary domains).

III. To determine if ultrahypofractionation is non-inferior to moderate hypofractionation and conventional fractionation with respect to patient-reported bowel function (assessed by EPIC-26 bowel domain).

IV. To compare patient-reported fatigue (assessed by Patient Reported Outcomes Measurement Information System [PROMIS]-Fatigue) between treatment arms.

1. To compare patient-reported treatment burden (assessed by COmprehensive Score for financial Toxicity [COST]) between treatment arms.

VI. To compare failure-free survival between treatment arms. VII. To compare metastasis-free survival based on molecular imaging between treatment arms.

VIII. To compare overall survival between treatment arms.

EXPLORATORY OBJECTIVES:

1. To compare patient-reported sexual function (assessed by EPIC-26 sexual domain) between treatment arms.

II. To compare patient-reported quality of life (assessed by European Quality of Life Five Dimension Five Level Scale Questionnaire [EQ-5D-5L]) between treatment arms.

OUTLINE: Patients are randomized to 1 of 2 arms.

ARM I: Patients undergo SBRT for a total of 5 treatments over 2 weeks.

ARM II: Patients undergo external beam radiation treatment (EBRT) for 20-45 treatments over 4 to 9 weeks.

Patients are followed up every 6 months for 5 years.