Efficacy Evaluation Using PET/CT For Malignant Tumor After Iodine-125 Seed Implantation

Part ⅠEfficacy and safety of radioactive iodine-125 seed implantation for patients with oligo-recurrence soft tissue sarcomasPurpose:To evaluate the efficacy and safety of computed tomography-guided radioactive iodine-125(125I)seed implantation for oligo-recurrence soft tissue sarcomas following surgical resection.Materials and methods:Patients with oligo-recurrence soft tissue sarcomas after curative surgical resection between June 2013 and December 2020 were included.The primary outcome measure was objective response rate according to the Response Evaluation Criteria in Solid Tumors(RECIST 1.1).The secondary outcomes included progression-free survival,overall survival,and safety profiles.Results:Twenty-nine patients receiving computed tomography-guided 125I seed implantation were included in the study.The objective response rates at 2-,6-,and 12-month follow-up were 48.3%,65.5%,and 40.9%,respectively.The median progression-free survival was 11.3 months.The median overall survival was 25.1 months,with a 1-and 2-year overall survival rate of 81.5%and 50.0%,respectively,No severe treatment-related adverse effects occured.PET/CT changed treatment plans in 14(29.8%)patients at least.Conclusion:125I seed implantation has the potential to be an effective and safe treatment for oligo-recurrence soft tissue sarcomas after surgical resection.Part ⅡComparison of different response evaluation criteria after radioactive iodine-125 seed implantationPurpose:To compare the Response Evaluation Criteria in Solid Tumors(RECIST)1.1,the European Organization for Research and Treatment of Cancer(EORTC)criteria and the Positron Emission Tomography Response Criteria in Solid Tumors(PERCIST 1.0)for response evaluation in patients treated with CT-guided 125I seed implantation.Materials and Methods:From August 2017 to November 2021,patients with histopathological unresectable malignancies were treated with 125I seed implantation,and 18F-FDG PET and/or enhanced CT scanning were performed 6-12 months after the procedure.The radiation responses were evaluated according to the RECIST 1.1,EORTC criteria and PERCIST 1.0,and the efficacies were compared among the three criteria.Results:Fifty-two lesions in 47 patients undergoing CT-guided radioactive 125I seed implantation were included in this study.Response evaluation were performed 6-12 months after the procedure,and 9 CR,6 PR,35 SD and 2 PD were found according to RECIST 1.1;15 CMR,21 PMR,10 SMD and 6 PMD were found according to EORTC;and 15 CMR,18 PMR,14 SMD and 5 PMD were found according to PERCIST 1.0.RECIST 1.1 and EORTC response classifications were coincident in 38.5%(20/52)patients;RECIST 1.1 and PERCIST 1.0 classifications were coincident in only 44.2%(17/52)patients;and EORTC and PERCIST 1.0 classifications were coincident in 84.6%(44/52)patients.Conclusion:Response evaluation after 125I seed implantation showed the EORTC was consistent with PERCIST 1.0 based on PET/CT,and RECIST 1.1 based on CT showed low consistency compared with the other two criteria.