Comparison of FDG-PET based tumor-to-blood standard uptake ratio and standard uptake value with patient outcome in NSCLC

Ziel/Aim:

It has been demonstrated that the tumor-to-blood standard uptake ratio (SUR) shows a higher linear correlation with the metabolic trapping rate of ¹⁸F-fluorodeoxyglucose (FDG) in comparison to the tumor standard uptake value (SUV). The aim of this study was to compare the association of SUR and SUV with patient outcome in NSCLC.
Methodik/Methods:
In total 72 patients (66.3±9.4 years) with newly diagnosed, untreated NSCLC were retrospectively included. All patients underwent FDG-PET/CT with dosages ranging from 179 to 254 MBq. Primary tumors were segmented using an
adaptive tumor-to-background thresholding algorithm (ROVER, ABX, Radeberg, Germany). The blood SUV was determined from a cylindrical three-dimensional region of interest placed in the aorta and the maximum SUR (SUR_max) was calculated as ratio of tumor SUV_max to blood SUV. The association of SUR_max and SUV_max with progression free survival (PFS) and overall survival (OS) was analyzed using the cox proportional hazard model. 95%-confidence intervals are given for hazard ratios (HR).
Ergebnisse/Results:
Progression was observed in 47 patients (65.3%) with a median time of PFS of 10.8 months (range, 0.7-31.4 months). 33 patients died (median OS, 15.4 months [range, 0.7-32.5 months]). The median follow-up time was 20.9 months
(range, 5.2-32.5 months). SUR_max was significantly correlated with SUV_max (Spearman's rho, 0.92; p<0.001). Cox regression model revealed a significant association of SUR_max with PFS (HR, 1.08 [1.01-1.15]; p=0.029) and a tendency for significance with OS (HR, 1.07 [0.99-1.16]; p=0.071) whereas no significant association was observed for SUV_max neither for PFS (HR, 1.01 [0.98-1.03]; p=0.548) nor for OS (HR, 1.01 [0.98-1.04]; p=0.558).
Schlussfolgerungen/Conclusions:
The maximum tumor-to-blood standard uptake ratio (SUR_max) showed a stronger association with patient outcome in comparison to SUV_max. These encouraging results have to be confirmed in further investigations.