Carbon-ion re-irradiation for recurrences after initial treatment of stage I non-small cell lung cancer with carbon-ion radiotherapy

Abstract Purpose To investigate carbon-ion radiotherapy (CIRT) for in-field recurrence of stage I non-small cell lung cancer (NSCLC) initially treated with CIRT. Materials and methods From January 2007 to March 2014, patients initially treated for stage I NSCLC with CIRT and relapsed in-field were candidates. Overall survival (OS) rate, local control (LC) rate, progressive free survival (PFS) rate, dose to the lungs and skin, and adverse effects were analyzed. Results Twenty-nine patients were eligible. Median age at re-irradiation was 74 years (range 53–90). Median observation period from the first day of re-irradiation was 29 months (4–88 months). Median prescribed dose was 46.0 Gy (RBE) as initial treatment and 66.0 Gy (RBE) in 12 fractions as re-irradiation. Two-year OS, LC, and PFS rates after re-irradiation were 69.0% (95% CI: 50.3–83.0), 66.9% (95% CI: 47.5–81.9), and 51.7% (95% CI: 34.1–68.9). Median skin maximum dose was 53.8 Gy (RBE) (range 4.4–103.1) and median of mean lung dose was 7.3 Gy (RBE) (range 2.6–14.0). There were no severer than grade 2 adverse effects except one (3.4%) grade 3 bacterial pneumonia, which was not considered radiation-induced. Conclusion CIRT for stage I NSCLC local recurrence is an acceptable definitive re-treatment.