A retrospective comparison of proton therapy and carbon ion therapy for stage I non-small cell lung cancer.

Background And Purpose: This retrospective study aimed to compare the clinical outcomes and late toxicities of proton therapy (PT) with those of carbon ion therapy (CIT) for stage I non-small cell lung cancer (NSCLC).

Material And Methods: A total of 111 patients who underwent particle therapy for stage I NSCLC between April 2003 and December 2009 were enrolled in this study. PT (n=70) and CIT (n=41) were delivered to total doses of 52.8-80 GyE in 4-26 fractions and 52.8-70.2 GyE in 4-26 fractions, respectively. The median follow-up time was 41 months.

Results: Differences in outcome between the PT and CIT groups regarding 3-year overall survival (72% and 76%, respectively), progression-free survival (44% and 53%, respectively), and local control (81% and 78%, respectively) were not statistically significant. In multivariate analysis, the type of treatment beam did not correlate with overall survival. The severity of late toxicities was comparable between the two groups.

Conclusions: Clinical results in the PT group were comparable to those in the CIT group. However, this study was a retrospective analysis of a highly heterogeneous population. Consequently, more homogeneous prospective data, large multicentric databases and, ideally, randomized trials are warranted.