182 - Quality of Life in Patients Enrolled in a Randomized Clinical Trial Evaluating Hypofractionated Radiotherapy for Intermediate Risk Prostate Cancer

N. S. Sanmamed^1,2, P. Chung³, I. Dayes⁴, A. Liu⁵, C. N. Catton³, J. Wright⁴, and J. M. Martin⁶; ¹Hospital Clinico San Carlos, Madrid, Spain, ²Hospital Clínico Universitario San Carlos, Madrid, ON, Spain, ³Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada, ⁴Juravinski Cancer Centre, Hamilton, ON, Canada, ⁵princess margaret cancer center, toronto, ON, Canada, ⁶Department of Radiation Oncology, Calvary Mater Newcastle & School of Medicine and Public Health, University of Newcastle, Newcastle, NSW, Australia

Purpose/Objective(s): The PROFIT study was designed to evaluate hypofractionated (HF) radiotherapy versus conventional fractionation (CF) for patients with intermediate-risk prostate cancer (IR-PCa). Similar efficacy and toxicity outcomes were previously reported. Here the long-term patient-reported outcomes (PROs) following treatment are presented. Materials/

Methods: A total of 1206 men with IR-PCa were randomized to receive 78 Gy in 39 fractions over 8 weeks (CF) or 60 Gy in 20 fractions over 4 weeks (HF). PROs were evaluated at baseline, 24 and 48 months using the Expanded Prostate Cancer Index Composite (EPIC), American Urological Association Symptom Score (AUASS) and, the 12-item Short Form Health Survey (SF-12) which combine 2 parts: a physical component summary (PCS) and a mental component summary (MCS). A minimally important difference (MID) was defined as a deterioration of domain- or subdomain-specific health-related quality of life (HRQoL) score at each time point compared to baseline = 0.5 standard deviation. Wilcoxon’s rank sum test was used for comparing all continuous measures, and Pearson’s Chi-squared test was used for comparing MID between two arms at each visit. Statistical significance was declared only when p<0.01. Statistical analyses were performed using R version 4.3.0.
Results: At baseline, 87.9% of patients in the CF and 88.5% in the HF arm provided completed forms dropping to 76.5% and 77.9% at 48 months, respectively. AUASS was similar and stable (median of 5) over time in both arms (p>0.2). No significant differences were found between the two arms in the urinary, bowel, sexual and hormonal domains or subdomains at any time point (p>0.02). The greatest decline over time occurred in sexual domain, decreasing =10 points from baseline to 24 months in both arms. SF-12 means of both, PSC and MSC, were similar and remained stable at all time points. At 24 months, MSC summary was significantly higher in CF arm (46 in CF arm vs 45 in HF arm; p 0.005), but not maintained at 48 months. The proportion of patients reporting MID was similar in both arms across all scores except in the bowel function at 48 months, where there was a significant difference in favor to the HF arm (51.5% in CF arm vs 39.5% in HF arm; p 0.001) and a trend in bowel summary (53.4% in CF arm vs 44% in HF arm; p 0.01) Overall treatment satisfaction was high in both arms, = 88% of patients were either satisfied or extremely satisfied with treatment.
Conclusion: Findings from the PROFIT study suggest no differences in urinary, bowel and sexual HRQoL between CF and HF. However, the proportion of patients reporting MID in bowel function at 48 months was significantly higher in the CF arm. At 24 months SF-12 MCS were significantly higher in the CF arm but no longer present at 48 months.