To evaluate the efficacy of different target area selection in implantation of ¹²⁵I radioactive seeds in treatment of non-small cell lung cancer.

Sixty patients with non-small cell lung cancer confirmed by pathology undergoing treatment in The 2^nd Hospital of Tianjin Medical University between January 2012 and December 2014 were enrolled. Patients were divided into two groups according to the sequence number, with 30 patients in each group. In group 1, target area was defined along the tumor margin based on lung-window CT, and treatment plan system (TPS) was used to make pre-operative plans and guide the implantation process of ¹²⁵I radioactive seeds. In group 2, target area was extended by 0.5 cm in all dimensions outside the tumor margin based on lung-window CT, and TPS was also used with the same implantation method. Patients were followed up for one year, chest CT and pulmonary function examinations were conducted, and the locoregional recurrence rate and status of radiation-induced pulmonary damage were observed in two groups. Chest CT examination performed 6 months after operation was utilized to evaluate the treatment efficacy according to response evaluation criteria in solid tumors.

All patients went through implantation procedure successfully, with no death during follow-up. There was no significant difference in effective rate between two groups (86.7% vs 90.0%; χ²=0.991, P=0.326). The recurrence rate in group 1 was significantly higher than that in group 2 (20.0% vs 6.7%; χ²=2.071, P=0.043). There was no significant difference between preoperative and postoperative lung function indicators of FEV₁% and DLCO% in two groups (P>0.05).

Extending the target area by 0.5 cm outside the tumor margin in implantation of ¹²⁵I radioactive seeds in treatment of non-small cell lung cancer can reduce the risk of locoregional recurrence, with no effect on treatment efficacy and no obvious radioactive lung injury.