Case-Matched Outcomes of Proton Beam and Intensity-Modulated Radiation Therapy for Localized Prostate Cancer

Abstract Purpose Although both intensity-modulated radiation therapy (IMRT) and proton beam (PBT) offer effective long-term disease control for localized prostate cancer (PCa), there are limited data directly comparing the 2 modalities. Methods The from 334 patients treated with conventionally fractionated (79.2 GyRBE in 44 fractions) PBT or IMRT were retrospectively analyzed. Propensity score matching was used to balance factors associated biochemical failure-free survival (BFFS). Age, race, comorbidities (not BFFS associates) remained imbalanced after matching. Univariable covariate-adjusted multivariable (MVA) Cox regression models determine if modality affected BFFS. Results Of patients, 176 (52.7%) included matched cohort exact National Comprehensive Cancer Network (NCCN) risk group. With a median follow-up time of 9.0 years (interquartile range [IQR]: 7.8-10.2 years), similar between arms 8-year estimates 85% (95% CI: 76%-91%) 91% 82%-96%, P = .39), respectively. On MVA, not significantly unmatched (hazard ratio [HR] 0.75, 95% 0.35-1.63, .47) (HR 0.87, 0.33-2.33, .78) cohorts. Prostate cancer–specific (PCSS) overall (OS) also (P > .05). However, an analysis, arm had fewer incidences secondary cancers within irradiated field (0.6%, 0.0%-3.1% versus 4.5%, 1.8%-9.0%, .028). Conclusions Both excellent PCa, no significant differences modalities BFFS, PCSS, OS patients. In cohort, malignancy noted group; however, owing low incidence patient characteristics groups, these strictly hypothesis generating require further investigation.