Comparative Outcomes after Definitive Chemoradiotherapy using Proton Beam Therapy versus Intensity-Modulated Radiation Therapy for Esophageal Cancer: A Retrospective Single-Institutional Analysis
Menée à partir de données portant sur 343 patients atteints d'un cancer de l'œsophage traité par chimioradiothérapie entre 2007 et 2014, cette étude compare, du point de vue de la survie sans progression, de la survie sans métastase distante, de la survie sans échec locorégional et de la survie globale, l'efficacité d'une protonthérapie et d'une radiothérapie avec modulation d'intensité
Purpose : To compare clinical outcomes between proton beam therapy (PBT) and intensity-modulated radiation therapy (IMRT) in patients with esophageal cancer (EC) treated with definitive chemoradiotherapy (CRT). Methods and Materials : From 2007 through 2014, 343 EC patients who received definitive CRT with either PBT (n = 132) or IMRT (n = 211) were retrospectively analyzed. Survival, recurrence, and treatment toxicity were compared between groups. Cox proportional hazards regression model was performed to test the association between patient/treatment variables and survival. Results : Patient/treatment variables were overall well balanced except for age and race. Compared to IMRT, PBT had significantly better overall survival (OS; P = 0.011), progression-free survival (PFS; P = 0.001), distant metastasis-free survival (DMFS; P = 0.031), as well as marginally better locoregional failure-free survival (LRFFS; P = 0.075). No significant differences in rates of treatment-related toxicities were observed between groups. On multivariate analysis, IMRT had worse OS (hazard ratio [HR], 1.454; P = 0.01), PFS (HR, 1.562; P = 0.001), and LRFFS (HR, 1.461; P = 0.041) than PBT. Subgroup analysis by clinical stage revealed considerably higher 5-year OS (34.6% vs. 25.0%, P = 0.038) and PFS rates (33.5% vs. 13.2%, P = 0.005) in PBT group for patients with stage III. However, no significant intergroup differences in survival were identified for stage I/II patients. Conclusions : Compared with IMRT, PBT might be associated with improved OS, PFS, and LRFFS, especially in EC patients with locally advanced disease. These results need confirmation by prospective studies.