Permanent Iodine-125 Seed Implantation for the Treatment of Nonresectable Retroperitoneal Malignant Tumors

PURPOSE: This study aimed to investigate the outcomes of permanent Iodine-125 ((125)I) radiotherapy for patients with unresectable retroperitoneal malignant tumor. METHODS: Twenty-six patients with retroperitoneal malignant tumors were implanted with (125)I seeds under ultrasound guidance from June 2012 to June 2015. The patients were then followed up for 3 to 36 months after the implantation. During the follow-up, pain relief, control of tumor growth, over survival rate, and complications were evaluated. RESULTS: Most of the patients (90%, 24/26) suffered from mild to severe pain before (125)I seed treatment. After 1-month treatment, 16 patients had 100% pain relief, 4 patients had at least 50% pain relief, and 4 patients had no response, showing 83.3% of pain relief response. Results of computed tomography scan after 2-month (125)I treatment indicated that 3 patients had complete remission in the tumor size, 20 patients had partial remission in tumor size, 2 patients were stable, and 1 patient had progressive disease, accounting for 88.4% response in tumor size remission. The median survival of the 26 patients was 11 months. The 1-year and 2-year overall survival rates were 46% and 27%, respectively. The median survival of the 5 patients with pancreatic cancer was 9.4 months. None of the patients had any severe complications. CONCLUSIONS: (125)I implantation could effectively relieve the pain in the patients with advanced primary or metastatic retroperitoneal malignant tumors and suppress local tumor progress.