3243 - Testosterone Recovery and Associated Impact on Patient-Reported Health-Related Quality of Life (HRQoL) after Treatment with 6 Months of GnRH Agonist with or without Abiraterone Acetate plus Prednisone

S. Moningi¹, P. L. Nguyen¹, D. Rathkopf², A. Zurita-Saavedra³, D. E. Spratt⁴, R. T. Dess⁵, S. Liauw⁶, R. Szmulewitz⁷, D. J. Einstein⁸, G. Bubley⁸, J. B. Yu⁹, Y. An¹⁰, A. C. Wong¹¹, F. Y. Feng¹², R. R. Mckay¹³, B. S. Rose¹⁴, K. Y. Shin¹⁵, M. E. A. Taplin¹⁶, M. A. Kollmeier¹⁷, and K. E. Hoffman¹⁸; ¹Department of Radiation Oncology, Brigham and Women’s Hospital/Dana-Farber Cancer Institute, Boston, MA, ²Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, ³Department of Genitourinary Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, ⁴Case Western, Cleveland, OH, ⁵Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, ⁶Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL, ⁷University of Chicago, Chicago, IL, ⁸Beth Israel Deaconess Medical Center, Boston, MA, ⁹Saint Francis Radiation Oncology, Hartford, CT, ¹⁰Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT, ¹¹University of California San Francisco, Department of Radiation Oncology, San Francisco, CA, ¹²Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, ¹³University of California San Diego, La Jolla, CA, ¹⁴Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA, ¹⁵Department of Data Science, Dana-Farber Cancer Institute, Boston, MA, ¹⁶Dana-Farber Cancer Institute, Boston, MA, ¹⁷Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, ¹⁸Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX

Purpose/Objective(s): The FORMULA-509 trial randomized patients receiving salvage radiation between 6 months of GnRH agonist plus bicalutamide or 6 months of GnRH agonist plus AAP/Apa. Here we evaluate factors associated with testosterone recovery after trial treatment and the impact of testosterone recovery on patient-reported HRQoL. Materials/

Methods: Testosterone was evaluated prior to treatment, at 3 months, at 6 months (end of systemic treatment), and at least every six months after treatment. Validated Expanded Prostate Cancer Index Composite (EPIC)-26 questionnaire was administered at baseline, end of treatment, and 1 year after completion of treatment. A change of 4 or more was considered a clinically meaningful change in the hormonal function domain. Log-rank test compared testosterone recovery between treatment groups. Wilcoxon rank sum and chi-square compared characteristics between those who did and did not recover testosterone. Multivariate logistic regression evaluated factors associated with lack of testosterone recovery. Chi-square evaluated frequency of clinically meaningful change in hormonal function.
Results: 345 patients were randomized (172 bicalutamide; 173 AAP/Apa). Median follow-up was 34 (6-53) months. There was no difference in testosterone recovery (>190 ng/dL) between treatment groups (p=0.10). 52.6% [95%CI 42.7-58.0] of patients recovered testosterone 6 months after treatment (bicalutamide: 51.2%; AAP/Apa 54.0%); 74.5% [69.8-79.2] 12 months (70.5%; 78.6%); 81.9% [77.7-86.1] 18 months (77.7%; 86.2%); and 88.8% [85.4-92.3] 30 months after treatment (85.8%; 91.9%). On univariate analysis, older age (median 67 vs 63 years; p<0.01), lower baseline testosterone (median 274 vs 379 ng/dL; p<0.01) and higher PSA at enrollment (median 0.3 vs 0.2; p=0.02) were associated with lack of testosterone recovery 1 year after treatment. Race, Gleason score, and treatment arm were not associated with testosterone recovery. On multivariate analysis, age at enrollment, baseline testosterone, and PSA at enrollment remained significant (all p <0.05). In the subset of patients who completed EPIC-26 1 year after treatment (n=219), those patients who did not have testosterone recovery were more likely to report a clinically meaningful decline in hormonal function relative to baseline than those who did achieve testosterone recovery, but it was not statistically significant (59% vs. 43% reporting clinically meaningful functional decline, p=0.06).
Conclusion: The addition of AAP/Apa did not lengthen time to testosterone recovery. Older men or those with lower baseline testosterone or higher PSA prior to treatment were less likely to recover testosterone 1 year after treatment. Patients who did not have testosterone recovery at 1 year were more likely to report decline in hormonal function.