Clinical outcomes of carbon‐ion radiotherapy for locally advanced non‐small‐cell lung cancer

The efficacy and safety of carbon‐ion radiotherapy (CIRT) for locally advanced non‐small‐cell lung cancer (LA‐NSCLC) remain unclear. We reported the clinical outcomes of CIRT for LA‐NSCLC. Data for 141 eligible patients who received CIRT between 1995 and 2015 were retrospectively analyzed. Local control (LC), locoregional control (LRC), progression‐free survival (PFS) and overall survival (OS) were calculated using the Kaplan‐Meier method. The median age was 75.0 years. Overall, 21 (14.9%), 57 (40.4%), 43 (30.5%) and 20 (14.2%) patients had T1, T2, T3 and T4 disease, respectively. Moreover, 51 (36.2%), 45 (31.9%), 40 (28.4%) and 5 (3.5%) patients had N0, N1, N2 and N3 disease, respectively. Furthermore, 34 (24.1%), 42 (29.8%), 45 (31.9%) and 20 (14.2%) patients had stages IIA, IIB, IIIA and ΙΙΙB disease, respectively. Overall, 62 (44.0%), 60 (42.6%), 8 (5.7%) and 11 (7.8%) patients had adenocarcinoma, squamous cell carcinoma, large cell carcinoma, and others, respectively. The median dose was 72.0 Gy (relative biological effectiveness). No patient received concurrent chemotherapy. Median follow‐up periods were 29.3 (1.6‐207.7) and 40.0 (10.7‐207.7) months for all patients and survivors, respectively. Two‐year LC, PFS and OS rates were 80.3%, 40.2% and 58.7%, respectively. Overall, 1 (0.7%), 5 (3.5%) and 1 (0.7%) patient developed Grades 4 (mediastinal hemorrhage), 3 (radiation pneumonitis) and 3 (bronchial fistula) toxicities, respectively. Multivariate analysis showed adenocarcinoma and N2/3 classification as significant poor prognosticators of PFS. CIRT is an effective treatment with acceptable toxicity for LA‐NSCLC, especially for elderly patients or patients with severe comorbidities who cannot be treated with surgery or chemoradiotherapy.