Abstract
567
Introduction: To explore the value of combination of volume-based parameters on pre-treatment MRI and 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) images, and find the optimal prognosticator for survival of locally advanced pancreatic cancer (LAPC) patients treated by SBRT and S-1 (a prodrug of 5-FU combined with two modulators). Materials and Methods: 17 patients with LAPC were enrolled, and before underwent SBRT and S-1 treatment, all patients performed by FDG PET/CT and diffusion weighted imaging (DWI) scan at 3.0 T (b = 600 s/mm2). The mean signal intensity (SIb = 600) of region-of-interest (ROI) were measured. Maximum standardized uptake value (SUVmax) was measured on FDG PET/CT images. Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were calculated under different thresholds respectively at the fixed(2.0,2.5,3.0) and relative(30%,40%,50%) value of SUVmax. Survival analysis was performed utilizing the univariate and multivariate analyses, and independent prognostic factors were determined by the Cox proportional hazard models, of which the predicting significance was further accessed by drawing survival curves, scatter diagram.
Results: At a median follow-up of 13.32(range, 3.6-25 months)months, no population withdrew the follow-up. Median overall survival(OS) and progression-free survival(PFS) were respectively 11.6 and 8.7 months. On univariate analysis, MTV(40%)<5.6cm3, TLG (40%)< 29.9, were significantly correlated with superior OS and PFS,. Multivariate analysis further demonstrated that both MTV (40%) and AD were independent prognostic factors for OS and PFS (p<0.05).
Conclusions: The combination of pretreatment SIb = 600 and FDG-PET/CT parameters, such as SUVmax, MTV, and TLG, may be significant prognostic factors in LAPC patients underwent SRBT and S1 therapy Keywords: Locally advanced pancreatic cancer, Stereotactic Body Radiation Therapy, FDG PET/CT, metabolic tumor volume, prognosis