Efficacy and dosimetry prognostic factors of image guided 125I seed implantation for locally recurrent soft tissue sarcoma.

11073 Background: To observe the effect of ultrasound / CT guided radioactive 125 I seed implantation in the treatment of recurrent soft tissue sarcoma and its relationship with physical dosimetry prognostic factors. Methods: The data of 37 patients with recurrent soft tissue sarcoma who received ultrasound/CT-guided 125 I seed implantation from November 2005 to December 2015 were retrospectively analyzed. The local progression-free survival rate and overall survival rate were evaluated. The relationship of local progression-free survival rate and overall survival with physical dosimetric parameters was analyzed. Results: Thirty-seven patients, 20 males and 17 females, with a median age of 53 years (16-79 years), received a median radiation dose of 60 Gy (28 Gy-120 Gy). The median tumor volume was 46.8 cm 3 (0.5-252.2 cm 3 ), the median particle activity was 0.67 mCi (0.4-0.84 mCi), and the median implanted particle number was 60 (3-158). The median follow-up time was 20 months (range: 1~144 months). The median overall survival time was 20.0 months (95% CI 16.4-23.6 months). The overall survival rates of 1, 3 and 5 years were 62.2%, 34.3% and 27.7% respectively. The median local progression-free time was 63.0 months. The 1-year, 3-year and 5-year local progression-free survival rates were 68.9%, 55.0% and 47.1%, respectively. Correlation analysis showed that HI was positively correlated with total survival and local progression-free survival (P = 0.001). Multivariate analysis showed that HI ( > 0.25) was an independent prognostic factor for long overall survival (P = 0.048, HR 0.39), and D 90 ( > 110 Gy) was an independent prognostic factor for long local progression-free survival (P = 0.024, HR 0.17). Conclusions: Ultrasound/CT guided 125 I seed implantation is a safe and effective method for the treatment of recurrent soft tissue sarcoma with high local control rate. The HI and D 90 of the postoperative plan maybe affect the therapeutic efficacy.