Proton and Carbon Ion Radiotherapy for Operable Early-Stage Lung Cancer: 3-Year Results of a Prospective Nationwide Registry

Abstract

The purpose of this analysis was to report subset analysis as to progression-free survival (PFS) and overall survival (OS) of particle-beam radiation therapy for operable early-stage lung cancer. Patients of early-stage lung cancer (T1-T2aN0) who were eligible for radical surgery but did not wish to undergo surgery were treated by proton-ion (PT) or carbon-ion (CT) radiation therapy and enrolled in Japanese prospective registry. In this analysis, PFS and OS by clinical stage, tumor location, pathological confirmation and particle-ion type were evaluated. A total of 274 patients were enrolled and included in efficacy and safety analyses. Most tumors were adenocarcinoma (44%), and 105 (38%) were not histologically confirmed and diagnosed clinically. 250 (91%) of 274 patients had tumors that were peripherally situated. 138 (50%) and 136 (50%) patients were treated by PT and CT, respectively. The median follow-up time for all censored patients was 42.8 months (IQR 36.7 - 49.0). No grade 3 or severe treatment-related toxicity was observed. 3-year PFS was 81% (95% CI;76-86) and OS was 93% (95% CI;89-96), respectively. As to particle-ion type, 3-year PFS were 79.0% and 81.9% in PT and CT (p = 0.19), and 3-year OS were 93.9% and 91.1% in PT and CT (P = 0.72), respectively. For PFS, pathological confirmation, clinical stage was significant factors but there were no significant differences by tumor location or particle-ion type; for OS, clinical stage was significant factor but there was no significant difference on pathological confirmation, tumor location or particle-ion type (Table1). Table 1. 3-year PFS and OS CONCLUSION: Particle therapy for operable early-stage lung cancer resulted in excellent 3-year OS and PFS on each subset.