Clinical application of CT-guided 125I seed interstitial implantation for recurrent rectum carcinoma

Objective: To explore the safety and clinical efficacy of CT-guided radioactive seed implantation in treating recurrent rectum carcinoma. Methods: CT-guided 125I radioactive seed implantation was carried out in 20 patients with recurrent rectal carcinoma. Treatment planning system was used preoperatively to reconstruct three dimensional image of the tumor and to calculate the estimated seed number and distribution. The tumor matched peripheral dose (MPD) of the radioactive seeds was 80-130 Gy. The radioactivity of the seeds was 0.5-0.8 mCi / seed and the median implanted seeds was 48(range 25-95) in number. CT scan was made immediately after the implantation to check the quality of the seeds. Change of pain score, tumor size and complications were recorded during the follow-up period. Results: Twenty cases composed of 12 males and 8 females,aged 38 to 78 years (median age of 62 years). The follow-up period lasted 2-28 months. On an average, 3 to 7 days after the procedure patients experienced significant pain relief. CT scan performed 2 months after the procedure revealed that complete relief (CR) of the tumor was seen in 2 cases, partial relief (PR) in 13 cases, no change (NC) in 3 cases and progression (PD) in 2 cases. The total effective rate (CR + PR) was 75%. The median survival time was 18.8 months. The survival rate of 1 and 2 years was 75% and 25% respectively. Two cases died of tumor deterioration and 3 cases died of extensive metastases. No complications such as frequent micturation, pain on urination and hematuria occurred during the follow-up period. Conclusion: CT-guided 125I radioactive seed implantation is a safe and effective interventional treatment for recurrent rectal carcinoma with reliable short-term efficacy and excellent anti-pain effect. (authors)