Computed tomography-guided implantation of 125I seeds brachytherapy for recurrent multiple pulmonary oligometastases: initial experience and results

PURPOSE To retrospectively evaluate the efficacy and safety of computed tomography (CT)-guided percutaneous interstitial brachytherapy using 125I radioactive seeds for multiple pulmonary metastatic tumors. MATERIAL AND METHODS Between September 2013 and December 2015, 22 patients with multiple pulmonary metastases, who after conventional chemotherapy and trans-arterial chemoembolization (TACE) therapy were considered unable to withstand stereotactic body radiation therapy (SBRT), received CT-guided 125I brachytherapy. Clinical data were studied retrospectively. A planning target volume of 90% (D90) was 120-160 Gy for 125I seeds with an activity of 25.9 MBq. A CT-based evaluation performed 1, 2, and 6 months' post-implantation enabled review of local control of tumors. RESULTS Twenty-two patients with 65 pulmonary metastases successfully completed treatment. The mean value for D90 for implantation for 125I seeds was 132 Gy. Complete response (CR) + partial response (PR) was documented in 81.54%, 78.46%, and 78.46% of patients at 1, 2, and 6 months after implantation, respectively. Fourteen out of 22 patients had CR, 3 had PR, 2 had stable disease (SD), and 3 had progressive disease (PD). Most of the metastases (CR + PR + SD; 87.69% after 6 months) were controlled by implantation. CONCLUSIONS CT-guided 125I brachytherapy is a safe and effective treatment for multiple pulmonary metastatic tumors, and can achieve good short-term local control, so long as the radiation dose is sufficient.