PurposeWe investigated the role of computed tomography (CT)-guided Iodine-125 (125I) seed implantation in combination with chemotherapy for the treatment of stage III non-small cell lung carcinoma (NSCLC).Material and methodsThe data from 182 patients with stage III NSCLC who were treated with radioactive 125I seed implantation between June 2002 and June 2009, and who received sequential platinum-based combination chemotherapy using the most common combination of platinum and gemcitabine, were retrospectively reviewed. The 182 patients received a prescribed dose of 110.0 Gy, with a median radioactivity of 0.70 mCi (range, 0.64-0.78 mCi, 2.37-3.26 × 107 Bq). The median number of 125I seeds was 38 pellets (range, 6-105 pellets). The median post-operation dose covering 100% of the target volume (D100) was 94.5 Gy (range, 54.6-125.5 Gy). The median D90 was 143.0 Gy (range, 121.6-184.0).ResultsThe 1-, 3-, and 5-year overall survival rates were 83.35%, 25.57%, and 11.34%, respectively; the median survival time was 24.76 months. At 1, 3, and 5 years, the local control rates were 92.01%, 86.51%, and 76.45%, respectively; the median local control time was 25.28 months. For patients with stage IIIA and IIIB NSCLC, the median survival times were 26.67 and 24.59 months, respectively (p = 0.2). Pre-treatment hemoglobin level, tumor volume, and postoperative D100 were significantly associated with survival. A total of 24 patients experienced pneumothorax (incidence rate, 13.20%), and 17 patients experienced hemothorax (incidence rate, 5.0%).ConclusionsCT-guided 125I seed implantation combined with chemotherapy is an effective, minimally invasive method for the treatment of stage III NSCLC. Furthermore, hemoglobin levels before treatment, D100, and the maximum diameter of the tumor may be prognostic factors in patients with NSCLC treated sequentially with radiotherapy and chemotherapy.