3273 - Testosterone Recovery after Cessation of Luteinizing Hormone-Releasing Hormone Antagonists in Treatment of Prostate Cancer
Presenter(s)
N. Lin1, A. Tam1, Q. Feng1, J. A. Shi1, C. J. Ladbury1, N. Correnti2, S. Zheng1, J. Y. C. Wong1, S. V. Dandapani1, S. M. Glaser1, A. Rock3, A. Chehrazi-Raffle4, A. Tripathi4, S. K. Pal4, T. B. Dorff4, and Y. R. Li1; 1Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, 2City of Hope National Medical Center, Duarte, CA, 3City of Hope, Duarte, CA, 4Department of Medical Oncology & Therapeutics Research, City of Hope National Medical Center, Duarte, CA
Purpose/Objective(s): Luteinizing hormone-releasing hormone (LHRH) antagonists, such as relugolix (oral) and degarelix (injection), are a class of androgen-deprivation therapy (ADT) that inhibits production of testosterone in treatment of prostate cancer (PCa). Prolonged testosterone recovery or non-recovery is a long-term toxicity associated with LHRH antagonists. Few existing studies report faster testosterone recovery (TR) with relugolix (3 months) than degarelix (9 months) and leuprolide (4 months). Limited studies have validated these findings and evaluated potential risk factors of non-recovery from LHRH antagonists, such as age.
Materials/Methods: We retrospectively reviewed the electronic medical records of 1903 PCa patients who received relugolix or degarelix at our institution as a part of curative-intent therapy between 01/2020-02/2025. After excluding patients treated with palliative intent (duration >36 months), 296 patients remained evaluable. Demographics, clinical staging, duration of ADT (relugolix prescription and degarelix injection dates), and testosterone values were collected. Time to Testosterone Recovery (TTR) was defined from date of prescription end date of relugolix or date of last degarelix injection to date of testosterone recovery to a laboratory-defined normal threshold (200 ng/dL).
Results: The median age was 73.6 years (range 49.5-99.1 years). The racial/ethnic distribution was 58.4% White (non-Hispanic/Latino), 13.9% Hispanic/Latino, 14.2% Asian/Pacific Islander, 6.1% Black/African American, and 7.4% Other. A total of 145 patients (49%) received relugolix, with a median duration of 8.2 months (range 0.03-35.7 months), and 151 patients (51%) received degarelix, with a median duration of 6.9 months (range 0.13-31.5 months). After a median follow-up time of 14.7 months (range 0.07-90.2 months), 162 patients (54.7%) achieved testosterone recovery with a median TTR of 4.25 months. A higher proportion of patients on relugolix (87; 60%) achieved TR compared to degarelix (75; 50%). Median TTR was shorter for patients receiving relugolix compared to degarelix (3.03 vs. 9.97 months; p<0.0001). Of the patients that achieved TR, 33 (20.4%) were <65 years old, 100 (61.7%) were 65-80 years old, and 29 (17.9%) were >80 years old. No statistically significant difference between the median TTR of these groups were reported (3.17 vs. 4.72 vs. 3.5 months; p=0.76).
Conclusion: Over half of patients receiving LHRH antagonists achieved TR to a laboratory-defined normal range with a median TTR of 4.25 months. Though the median duration of relugolix was longer than degarelix, patients receiving relugolix had a shorter median TTR. No association was found between age and TTR. Future studies with larger patient populations are needed to further understand predictors of delayed TR and evaluate how shorter TTR impacts cancer control. Better understanding of how medication administration affects treatment toxicities is needed to promote PCa patient quality of life.