Maintenance of patient-reported health-related quality of life post neoadjuvant relugolix prior to the initiation of prostate radiation therapy.

Introduction: Studies have demonstrated that injectable GnRH receptor agonists further suppress cancer progression when paired with radiotherapy (RT) in patients with intermediate- to high-risk prostate adenocarcinoma. Relugolix is a newly available oral GnRH receptor antagonist that achieves swift and profound castration (total testosterone <20 ng/dl) at high rates, which may shape patients' health-related quality of life. The main objective of this prospective study was to explore the effects of neoadjuvant relugolix on health-related quality of life in prostate cancer patients immediately prior to stereotactic body radiation therapy (SBRT). Methods: Patients treated at Georgetown between January 2021 and September 2023 with neoadjuvant relugolix per an institutional protocol were included in the study (IRB 12-1775). The five-item EQ-5D-3L, a well-established tool for quantifying patient-reported health status, was administered to each patient at baseline (prior to relugolix treatment) and again 1 h before the start of SBRT. Higher EQ Visual Analog Scale (VAS) overall scores reflected better quality of life (range 0 to 100). In line with the questionnaire framework, individual elements (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression) were rated on a three-point scale from 1 (no problems) to 3 (severe problems). McNemar's test and paired-sample t-test were performed to analyze changes pre- and post-relugolix treatment. Our investigation determined clinical significance based on minimally important difference (MID) calculated as 0.5 times the baseline standard deviation. Results: Among the 87 patients, average age was 71 years, 42% were non-white, and 24% were considered obese (BMI ≥30 kg/m²). Relugolix was initiated a median of 4 months before SBRT initiation (IQR: 3.9-5.4), with 87% of patients reaching profound castration (<20 ng/dl). The VAS overall score was notably higher at baseline (mean ± SD: 82 ± 10) compared to the paired score before RT (79 ± 14, p = 0.02), although this difference was not clinically significant. No statistically or clinically significant changes were observed in any of the five individual items. Conclusion: The use of neoadjuvant relugolix prior to prostate radiation therapy had no clinically significant impact on patient-reported health-related quality of life. Moreover, no statistically significant reductions were observed in any of the five individual health-related quality of life measures. As a key direction for future research, relugolix-associated changes to healthy-related quality of life should be contrasted to those brought about by injectable GnRH agonists.