The utility of quantitative ۱۸F-FDG PET/CT-derived parameters as prognostic factors for predicting overall survival in radioiodine-refractory differentiated thyroid cancer

Objective: This study investigates the relationship between quantitative ۱۸F-FDG PET/CT metabolic parameters and overall survival (OS) in patients with radioiodine-refractory differentiated thyroid cancer (RAI-R DTC).Patients and Methods: We conducted a prospective analysis of ۱۲۷ patients with RAI-R DTC. Quantitative metabolic parameters including SUVmax, SUVmean, SULpeak, total metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were assessed in ۱۸F-FDG -avid recurrent or metastatic lesions via ۱۸F-FDG PET/CT imaging. Patients were monitored for disease progression and mortality for at least one year post PET/CT imaging. Receiver operating characteristic (ROC) curves were used to establish cut-off values for predicting ۵-year mortality, while the Kaplan-Meier method estimated the ۵-year survival rate. Univariate and multivariate Cox regression analyses identified prognostic factors associated with OS.Results: The metabolic parameters derived from ۱۸F-FDG PET/CT demonstrated high sensitivity and specificity for predicting ۵-year OS. ROC curve analysis established optimal cut-off values for SUVmax (۲۰.۲۷ g/mL), SUVmean (۶.۱ g/mL), SULpeak (۸.۰۶ g/mL), TLG (۴۵.۷۴ g/mL × cm³), and MTV (۷۶۰۰ mL) (AUC: ۰.۸۵, ۰.۸۱۲, ۰.۸۶۲, ۰.۹۰۶, and ۰.۸۱۷, respectively; p < ۰.۰۰۱). Kaplan-Meier analysis revealed significantly lower OS in patients with higher values of these parameters compared to those with lower ones (survival rates: ۴۲.۱% vs. ۹۵.۶%, ۶۵.۵% vs. ۹۶%, ۵۲.۳% vs. ۹۶.۳%, ۴۶.۵% vs. ۹۷.۳%, and ۵۲.۸% vs. ۹۸.۳%, respectively; p < ۰.۰۰۱). Univariate Cox regression identified SUVmax, SUVmean, SULpeak, TLG, and MTV as significant predictors of ۵-year OS (p < ۰.۰۵). In multivariate analysis, SULpeak and MTV emerged as independent predictors of OS.Conclusion: Quantitative ۱۸F-FDG PET/CT-derived parameters are significant predictors of ۵-year OS, exhibiting high sensitivity and specificity. Elevated values of these parameters correlate with increased mortality rates. Our findings suggest that SULpeak and MTV are independent prognostic factors for ۵-year OS in patients with radioiodine-refractory DTC.

کلیدواژه ها:

Differentiated thyroid cancer ، radioiodine-refractory ، ۱۸F-FDG PET/CT ، ۱۸F-FDG metabolic parameters ، Overall survival