Objective:To evaluate clinical prognosis and prognostic factors of patients with early stage (Ⅰ stage) and locally advanced (Ⅱ/Ⅲ stage) lung cancer treated with carbon ion radiotherapy (CIRT).Methods:Clinical data, treatment, adverse reactions, survival and so on of 54 lung cancer patients who received CIRT and follow-up in the Heavy Ion Center of Wuwei Cancer Hospital of Gansu Province from March 2020 to September 2022 were retrospectively analyzed. The survival curve was plotted using Kaplan-Meier method. Difference tests were performed using log-rank test. Logistic regression analysis was used to identify prognostic factors.Results:According to inclusion and exclusion criteria, 54 patients were enrolled in the study, including 10 patients with early stage lung cancer and 44 patients with locally advanced lung cancer. The median follow-up time for 10 patients with early stage lung cancer was 11.0 (6.75, 17.25) months, and the median dose of irradiation was 60 Gy [relative biological effect (RBE)]. Upon the last follow-up, 3 patients had complete response (CR) and 3 patients had partial response (PR). Four patients had stable disease (SD) and no progressive disease (PD). The 1-year and 2-year local control rates (LCR), progression-free survival (PFS) rates and overall survival (OS) rates were 100%. During treatment and follow-up, 2 patients developed grade 1 radiation pneumonia, 1 case of grade 2 radiation pneumonia, 1 case of chest wall injury (chest wall pain), and there were no adverse reactions greater than grade 2. The median follow-up time of 44 patients with locally advanced stage was 12.5 (4.25, 21.75) months, and the median irradiation dose was 72 Gy (RBE). Thirty-two (73%) patients received concurrent chemotherapy during treatment, 20 (45%) patients received sequential chemotherapy after treatment, 14 (32%) patients received immune maintenance therapy and 3 (7%) patients obtained PD and received targeted drugs. Upon the last follow-up, 3 (7%) patients had CR, 17 (39%) patients had PR, 19 (43%) patients obtained SD, and 5 (11%) patients had PD. The 1-year and 2-year LCR were 96.0% and 87.3%, 90.9% and 84.1% for the 1-year and 2-year PFS rates, and 93.2% and 86.4% for the 1-year and 2-year OS rates, respectively. The median OS and PFS of patients were not reached. Multivariate logistic regression analysis showed that maintenance therapy after radiotherapy ( P=0.027) and clinical target volume (CTV) irradiation volume ( P=0.028) were the factors affecting PFS. Simultaneous chemoradiotherapy ( P=0.042) and maintenance therapy after radiotherapy ( P=0.020) were the factors affecting OS. And gross tumor volume (GTV) ≥215 ml ( P=0.068) might be an independent risk factor for grade 2 and above radiation pneumonia. Conclusions:The domestic carbon ion system has definite clinical effect and controllable toxic and side effects in the treatment of early stage and locally advanced lung cancer. The combination of synchronous chemotherapy and further maintenance treatment can significantly improve clinical prognosis of patients without significantly increasing the risk of toxic and side effects.

Objective:To compare the adverse reactions, efficacy and survival rate of carbon ion beam irradiation in the elective lymph node (ENI) drainage area of locally advanced non-small cell lung cancer (LA-NSCLC) with relative biological effect (RBE) dose of 48 Gy using 16 and 12 fractions.Methods:A total of 72 patients with pathologically confirmed LA-NSCLC admitted to Wuwei Heavy Ion Center of Gansu Wuwei Tumor Hospital from June 2020 to December 2021 were enrolled and simple randomly divided into groups A and B, with 36 patients in each group. Patients in groups A and B were treated with carbon ion beam irradiation to the lymph node drainage area with 48 Gy (RBE) using 16 and 12 fractions. The acute and chronic adverse reactions, efficacy and survival rate were observed. The survival curve was drawn by Kaplan-Meier method. Difference test was conducted by log-rank test.Results:The median follow-up time was 13.9 (8.8-15.7) months in group A and 14.6 (6.3-15.9) months in group B. Sixteen (44.4%) patients were effectively treated in group A and 9 (25%) patients in group B. Thirty-four (94.4%) cases achieved disease control in group A and 30 (83.3%) cases in group B. Statistical analysis showed that the overall survival rate in group B was similar to that in group A ( χ2=1.192, P=0.275). Comparison of planning parameters between two groups showed CTV volume, D mean, V 5 Gy(RBE), V 20 Gy(RBE) and V 30 Gy(RBE) of the affected lung, cardiac V 20 Gy(RBE), V 30 Gy(RBE) and D mean, esophageal V 30 Gy(RBE), V 50 Gy(RBE), D max and D mean, D max of the trachea and spinal cord had no significant difference (all P>0.05). No grade 3 or 4 adverse reactions occurred in the enrolled patients during treatment and follow-up. No statistical differences were observed in the acute radiation skin reaction ( χ2=5.134, P=0.077), radiation esophagitis ( χ2=1.984, P=0.371), and advanced radiation pneumonia ( χ2=6.185, P=0.103) between two groups. Conclusions:The two dose fractionation modes of carbon ion therapy system are equally safe in the mediastinal lymphatic drainage area of LA-NSCLC, and the adverse reactions are controllable. The long-term efficacy still needs further observation.