181 - Long-Term Patient-Reported Health-Related Quality of Life in the Randomized FORMULA-509 Trial of Salvage Radiotherapy and 6 Months of GnRH Agonist with Either Bicalutamide or Abiraterone Acetate Plus

K. E. Hoffman¹, P. L. Nguyen², D. Rathkopf³, A. Zurita-Saavedra⁴, D. E. Spratt⁵, R. T. Dess⁶, S. Liauw⁷, R. Szmulewitz⁸, D. J. Einstein⁹, G. Bubley⁹, J. B. Yu¹⁰, Y. An¹¹, A. C. Wong¹², F. Y. Feng¹³, R. R. Mckay¹⁴, B. S. Rose¹⁵, K. Y. Lee¹⁶, A. Kibel¹⁷, M. E. A. Taplin¹⁶, and M. A. Kollmeier¹⁸; ¹Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, ²Department of Radiation Oncology, Brigham and Women’s Hospital/Dana-Farber Cancer Institute, Boston, MA, ³Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, ⁴MD Anderson Cancer Center, Houston, TX, ⁵Case Western, Cleveland, OH, ⁶Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, ⁷Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL, ⁸University of Chicago, Chicago, IL, ⁹Beth Israel Deaconess Medical Center, Boston, MA, ¹⁰Saint Francis Radiation Oncology, Hartford, CT, ¹¹Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT, ¹²University of California San Francisco, Department of Radiation Oncology, San Francisco, CA, ¹³Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, ¹⁴University of California San Diego, La Jolla, CA, ¹⁵Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA, ¹⁶Dana-Farber Cancer Institute, Boston, MA, ¹⁷Brigham and Womens Hospital, Boston, MA, ¹⁸Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY

Purpose/Objective(s): The randomized FORMULA-509 trial demonstrated that for patients with a PSA >0.5 after prostatectomy receiving salvage radiation and 6 months of GnRH Agonist, the addition of abiraterone acetate plus prednisone (AAP) and apalutamide (Apa) improved metastasis-free survival compared to bicalutamide. Here we present the patient-reported health-related quality of life (HRQoL) results through three years. Materials/

Methods: Validated questionnaires were administered at baseline, end of treatment, and 1 and 3 years after completion of treatment. Patients completed Expanded Prostate Cancer Index Composite (EPIC)-26, PROMIS Fatigue, and Saint Louis University Mental Status Exam (SLUMS). EPIC-26 is scored from 0 to 100 with 100 indicating higher function. PROMIS Fatigue is scored using a standardized T score with higher score indicating greater fatigue. SLUMS is scored from 0 to 30 with 27 to 30 interpreted as normal, 21 to 26 as mild neurocognitive disorder and 20 or less as dementia. Scores between treatment arms were compared using the t-test. Results were interpreted using established thresholds for clinically meaningful differences (4-6 for EPIC-26 hormonal domain, 5-10 for PROMIS Fatigue).
Results: 345 patients were randomized (172 bicalutamide; 173 AAP/Apa). Completion rates at baseline, end of treatment, 1 year, and 3 years, were 96%, 80%, 70% and 57% for EPIC-26; 95%, 79%, 67% and 57% for PROMIS Fatigue; and 96%, 80%, 70% and 34% for SLUMS. From baseline to end of treatment, both arms demonstrated clinically meaningful declines in EPIC-26 hormonal domain (median change -15 bicalutamide; -15 AAP/Apa) and increase in PROMIS Fatigue (median change 6 bicalutamide; 7.4 AAP/Apa). From end of treatment to 1 year after treatment patient-reported HRQoL improved to near baseline for both EPIC-26 hormonal function (bicalutamide median score baseline: 95, end: 75, 1 year: 90; AAP/Apa baseline: 95, end: 75, 1 year: 90) and fatigue (bicalutamide median score baseline: 43.1, end: 48.6, 1 year: 46.0; AAP/Apa baseline: 43.1, end: 51.0, 1 year: 46.0) with further improvement in EPIC-26 hormonal function at 3 years (bicalutamide: 95.0; AAP/Apa: 95.0) and stable fatigue at 3 years (bicalutamide: 46.0; AAP/Apa: 46.0).cMedian SLUMS score was within normal range at baseline (27 bicalutamide; 27 AAP/Apa), end of treatment (28, 28) and 1 (27, 27) and 3 (27, 27) years after treatment. There was no difference in patient-reported hormonal function, fatigue, or mental status between treatment arms, at end of treatment (p=0.40; 0.78; 0.41 respectively), 1 year after treatment (p=0.78; 0.89; 0.76), and 3 years after treatment (p=0.45; 0.95; 0.86). Conclusion: The addition of AAP/Apa improved oncologic outcomes without causing a detectable difference in patient-reported hormonal function, fatigue, or mental status compared to bicalutamide through three years after treatment.