The SUGAR Study; SBRT and Relugolix) for Prostate Cancer

Unfavorable Intermediate Risk (UIR) Prostate Cancer is prostate cancer that is localized and curable but may require more treatment than external beam radiotherapy (EBRT) alone. In contrast, favorable intermediate risk (FIR) prostate cancer can be treated by EBRT alone. There is evidence that some prostate cancer that is classified through clinical factors as FIR can act more aggressively if also associated with a high risk gene expression score. This type of prostate cancer (traditionally favorable intermediate risk, but with a gene signature that predicts for aggressive disease) presents a treatment dilemma. Recent evidence suggests that androgen deprivation therapy (ADT) is generally beneficial for intermediate risk prostate cancer and so it is possible that these patients (with favorable intermediate risk based on non-genetic factors but with high genetic risk) may also benefit. However, ADT causes very bothersome side effects including hot flashes, fatigue, sexual disfunction, and in some cases, heart problems. In order to balance the benefit and harms of ADT in combination with radiation, we could reduce the length of ADT and make it precisely overlap with radiation treatment. The oral ADT medication Relugolix (Orgovyx) is ideal for this purpose. In addition to shortening ADT, it is important to measure any potential benefit when ADT is added to stereotactic body radiotherapy (SBRT). SBRT is a shorter and more intense version of standard fractionation EBRT. Therefore, a multicenter randomized phase II study comparing prostate cancer control and quality of life with SBRT + Ultrashort GNRH Antagonist Relugolix (SUGAR) vs. SBRT alone for a category of clinicogenomic unfavorable intermediate risk patients with favorable clinical features and high risk genetic features.