CT-guided 125I seed brachytherapy for abdominal metastatic lymph nodes

Objective: To investigate the safety and clinical efficacy of CT-guided radioactive seed 125I implantation in treating abdominal and retroperitoneal metastatic lymph nodes. Methods: Twenty-seven patients with pathologically proved abdominal malignancy (17 males and 10 females) were enrolled in this study. The primary tumors included liver cancer (n=13), pancreatic cancer (n=8) and gastric cancer (n=6). A total of 31 abdominal and peritoneal metastatic lymph nodes (diameter of 2.2-4.7 cm) were detected and CT-guided radioactive seed 125I implantation was carried out. Halarism 125I experience formula was used to design the distribution of seed 125I. Under CT guidance, 125I seeds were implanted into the metastatic lymph nodes at a distance interval of 1.0-1.5 cm. After implantation, CT scanning was immediately performed to check the distribution of 125I seeds to observe the possible complications. CT or PET-CT re-examination was performed at 3 months after 125I seed implantation. Results: Of the 27 patients, 125I seed implantation was successfully accomplished in 25 (92.6%) at the first time and the particle distribution met the radioactive requirements well. In the remaining 2 patients the particle distribution did not meet the requirements and replacement of 125I seed had to be made. In this group, 8 patients had severe pain before treatment and in six of them the pain was markedly relieved at 1-3 weeks after seed 125I implantation, with a response rate of 75.0%. The patients were followed up for three months and all the 27 patients survived. According to the results of CT or PET-CT re-examination, 12 of 27 patients (44.4%) achieved complete remission (CR), 8 (29.6%) achieved partial remission (PR), 4 (14.8%0 showed no change (NC) and 3 (11.1%) had progressive disease (PD). The overall response rate was 74.1% (20/27). No severe complications, such as acute pain, massive bleeding, infection and bone marrow suppression, occurred. Conclusion: For the treatment of abdominal and retroperitoneal metastatic lymph nodes CT-guided interstitial implantation of radioactive seed 125I is effective, minimal invasive and safe with few complications. (authors)