The utility of quantitative 18F-FDG PET/CT-derived parameters as prognostic factors for predicting overall survival in radioiodine-refractory differentiated thyroid cancer

TL;DR

This study shows that specific PET/CT imaging parameters can predict survival in patients with a type of thyroid cancer that does not respond to standard treatment.

Contribution

The study identifies SUVpeak and MTV as independent prognostic factors for 5-year survival in radioiodine-refractory differentiated thyroid cancer.

Findings

SUVpeak and MTV are independent predictors of 5-year overall survival in radioiodine-refractory differentiated thyroid cancer.

Quantitative PET/CT parameters like SUVmax, SUVmean, and TLG show high sensitivity and specificity for predicting survival.

Higher values of metabolic parameters correlate with significantly lower survival rates in patients.

Abstract

This study investigates the relationship between quantitative 18F-FDG PET/CT metabolic parameters and overall survival (OS) in patients with radioiodine-refractory differentiated thyroid cancer (RAI-R DTC).

We conducted a prospective analysis of 127 patients with RAI-R DTC. Quantitative metabolic parameters including SUVmax, SUVmean, SUVpeak, total metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were assessed in 18F-FDG -avid recurrent or metastatic lesions via 18F-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 5-year mortality, while the Kaplan-Meier method estimated the 5-year survival rate. Univariate and multivariate Cox regression analyses identified prognostic factors associated with OS.

The metabolic parameters derived from 18F-FDG PET/CT demonstrated high sensitivity and specificity for predicting 5-year OS. ROC curve analysis established optimal cut-off values for SUVmax (20.27 g/mL), SUVmean (7.46 g/mL), SUVpeak (7.8 g/mL), TLG (45.74 g/mL×cm³), and MTV (5.78 cm3) (AUC: 0.82, 0.78, 0.82, 0.82, and 0.86, respectively; p<0.001). Kaplan-Meier analysis revealed significantly lower OS in patients with higher values of these parameters compared to those with lower ones (survival rates: 42.1% vs. 95.6%, 65.5% vs. 96%, 52.3% vs. 96.3%, 46.5% vs. 97.3%, and 57.3 % vs. 98.3%, respectively; p<0.001). Univariate Cox regression identified SUVmax, SUVmean, SUVpeak, TLG, and MTV as significant predictors of 5-year OS (p<0.05). In multivariate analysis, SUVpeak and MTV emerged as independent predictors of OS.

Quantitative 18F-FDG PET/CT-derived parameters are significant predictors of 5-year OS, exhibiting high sensitivity and specificity. Elevated values of these parameters correlate with increased mortality rates. Our findings suggest that SUVpeak and MTV are independent prognostic factors for 5-year OS in patients with radioiodine-refractory DTC.

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