CT-guided ¹²⁵I seed implantation in the treatment of malignant pulmonary metastases

Objective: To evaluate the clinical outcomes and the prognostic factors in patients with pulmonary metastases treated with CT-guided radioactive ¹²⁵I seed implantation (CTRISI). Methods: A total of 50 patients were treated with implantation of ¹²⁵I radioactive seeds under computed tomography (CT) guidance or combined with surgical resection. There were 10 (20%) patients with colorectal cancer, 8 (16%) patients with malignant fibrous histiocytoma, 5 (10%) patients with sarcoma, 22 (44%) patients with other cancer, respectively. CTRISI was the only treatment in 45 patients (90%) and combined with surgical resection in 5 (10%). The local control rate, the survival rate and the factor associated with overall survival were evaluated. Results: The D_90% was (112.3±12.2) Gy, the V₉₀ was 91.3%±8.2%, and the postoperative matched peripheral dose (MPD) was 106.2 Gy. The local control rate for 1-, 2-, 3-, 4-, 5-year were 95.8%, 86.5%, 56.6%, 42.4%, 31.1%, respectively. At a mean follow-up of 26 months (7-74 months), 6 patients were alive. The median survival time was 27.1 months. The survival rate for 1-, 2-, 3-, 4-, 5-year were 83.4%, 52.3%, 38.7%, 20.3%, 13.7%, respectively. Lesion size ≤4 cm or >4 cm was an important prognostic factor associated with overall survival(χ² = 4.621, P < 0.05) and disease-free survival(χ² = 7.548, P < 0.05). Conclusions: CTRISI is safe in these patients with pulmonary metastases, with promising results. Surgical resection remains the standard for resectable patients, while CTRISI alone or combined with surgery might offer an alternative in selected patients. (authors)