Prognostic value of pretreatment FDG PET-CT for short-term efficacy of radioactive iodine-125 seed implantation in patients with NSCLC

Objective: To analyze the short-term clinical effect of radioactive iodine-125 seed implantation (125I-SI) for non-small cell lung cancer (NSCLC) patients and explore the correlation between the related metabolic parameters of pretreatment FDG PET-CT and the short-term efficacy of 125I-SI in patients with NSCLC, so as to provide useful reference for 125I-SI treatment. Methods: Retrospective analysis was performed on 46 patients with NSCLC, who received 125I-SI treatment for lung tumors in Tianjin First Central Hospital from January 2016 to December 2018. The correlation among D90, gender, pathological pattern, age, maximum tumor diameter, MTV, SUVmax, SUVpeak, SUVmean, TLG, High metabolic tumor cell ratio (HMR) and CEA with short-term efficacy of 125I-SI was analyzed by two independent-sample t-test, Mann-Whitney U-test or Chi-squared test and binary logistic regression. Results: One month after 125I-SI, 0 cases were CR, and 4 cases were PR, and the total effective rate was 8.7%. After 3 months, there were 2 cases of CR, and 25 cases of PR, with a total effective rate of 58.7%; after 6 months, there were 5 cases of CR, and 27 cases of PR, with a total effective rate of 69.6%. D90 (P = 0.028, OR:1.075,95%CI:1.008-1.147), MTV (P = 0.026, OR: 0.918,95%CI: 0.851-0.990), HMR (P = 0.020, OR: 0.003,95%CI: 0-0.407) were independent predictors for the short-term efficacy. The predictable accuracy of MTV was medium (AUC=0.781; cutoff value=44.58). However, the predictable accuracy of D90 and HMR was low, with both AUC of 0.650 (the cutoff =127.8Gy and the cutoff=0.27, respectively). Conclusion: 125-SI is an effective therapy with few complications in NSCLC patients. Small MTV, high D90 and low HRM were linked with better local control of 6 months after 125-SI.