Survival and prognostic factors analysis of carbon ion radiotherapy for limited-stage small cell lung cancer

Objective To investigate the clinical efficacy, safety and prognostic influencing factors of carbon ion radiotherapy (CIRT) in patients with limited-stage small-cell lung cancer (LS-SCLC). Methods The clinical data of 39 patients with LS-SCLC who received CIRT from June 2020 to August 2026 were retrospectively analyzed. Survival outcomes and adverse reactions were evaluated, and Cox regression was used to analyze prognostic factors. Results All patients completed the treatment. The 3-month objective response rate (ORR) was 64.10%. The 1- and 2-year local control rates were both 91.2%. The 1- and 2-year overall survival (OS) rates were 91.65% and 62.45%, with a median OS of 44 months. The 1- and 2-year progression-free survival (PFS) rates were 72.00% and 47.77%, with a median PFS of 24 months. Serum levels of NSE, CYFRA21-1, SCC and CEA decreased significantly after treatment. Acute treatment-related adverse reactions were mainly grade I-II and could be relieved after symptomatic treatment. Stratified Cox regression indicated that KPS score was an independent protective factor for OS. Univariate analysis suggested that the magnitude of post-treatment reduction in SCC and CYFRA21-1 was potentially associated with survival outcomes. Conclusion CIRT achieves favorable local tumor control with low acute radiotherapy-related toxicity, and can serve as an alternative therapeutic option for LS-SCLC. This is a single-center, small-sample retrospective study, and the conclusions regarding efficacy and prognosis need to be further verified in larger-sample cohorts.