Clinical report of two dose fractionation modes using carbon ion beam therapy in the lymph node drainage area for lung cancer / 中华放射肿瘤学杂志

ABSTRACT

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.