2917 - Comparison of Patient-Reported Side Effects Between Leuprolide and Relugolix in Prostate Cancer Patients Receiving Radiation Therapy

Purpose/Objective(s): Androgen deprivation therapy (ADT) is commonly used in the treatment of prostate cancer but is associated with significant side effects. Leuprolide, a gonadotropin-releasing hormone (GnRH) agonist, and relugolix, an oral GnRH antagonist, differs in mechanism of action and delivery method. This study evaluates differences in patient-reported side effects between prostate cancer patients treated with Leuprolide versus Relugolix.

Materials/Methods: At a single institution, patient-reported outcomes were collected prospectively as part of routine clinical care using the validated Expanded Prostate Cancer Index Composite–Clinical Practice (EPIC-CP) to assess energy, hot flashes, mood, sexual function, erections, and orgasm. Patients were grouped by ADT type. Outcomes were analyzed at 0–3, 3–6, 6–12, and =12 months post-ADT. Responses were dichotomized as presence versus absence of a moderate/severe problem. Chi-square testing compared groups at each interval.

Results: A total of 774 patients were included (Leuprolide =661; Relugolix=113). The mean duration of ADT was 6.8 months overall (Leuprolide = 7.2 months vs. Relugolix= 6.3 months), and the average age was 68 years. Fatigue and hot flashes were similar between groups at all time points. Sexual function and orgasm impairment were common and did not differ between groups. Depressed mood was less frequently reported with relugolix at 6–12 months (5.6% vs 20.1%, p<0.05) post ADT cessation, with no other mood differences observed. Erectile dysfunction increased over time in both groups; rates were higher with relugolix at =12 months (95.0% vs 80.3%) but were not statistically significant.

Conclusion: Overall post-ADT symptom burden was comparable between agents; however, differences in mood were observed beyond 6 months following treatment completion. Although relugolix and leuprolide have different mechanisms of action, whether there is a difference in quality-of-life impact post ADT cessation remains unclear.