Patient-Reported Quality of Life Outcomes after Moderately Hypofractionated and Normofractionated Proton Therapy for Localized Prostate Cancer

Abstract

We retrospectively evaluated the three-year patient-reported quality of life (QOL) after moderately hypofractionated proton therapy (MHPT) for localized prostate cancer in comparison with that after normofractionated PT (NFPT) using the Expanded Prostate Cancer Index Composite-50. Patients who received MHPT (60–63 Gy (relative biological effectiveness equivalents; RBE)/20– 21 fractions) (n = 343) or NFPT (74–78 Gy (RBE)/37–39 fractions) (n = 296) between 2013 and 2016 were analyzed. The minimum clinically important difference (MCID) threshold was defined as one-half of a standard deviation of the baseline value. The median follow-up was 56 months and 83% completed questionnaires at 36 months. Clinically meaningful score deterioration was observed in the urinary domain at 1 month in both groups and in the sexual domain at 6–36 months in the NFPT group, but not observed in the bowel domain. At 36 months, the mean score change for urinary summary was −0.3 (MHPT) and −1.6 points (NFPT), and that for bowel summary was +0.1 and −2.0 points; the proportion of patients with MCID was 21% and 24% for urinary summary and 18% and 29% for bowel summary. Overall, MHPT had small negative impacts on QOL over three years, and the QOL after MHPT and NFPT was similar.