Necrosis on Pre-treatment 18F-FDG PET/CT Predicts Worse Prognosis in Patients With Stage IIIB Non-small Cell Lung Cancer.

Abstract

\n ObjectiveThe presence of pathological necrosis in the tumor is known to be a factor indicating worse survival. Our study aimed to define necrosis in staging 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in patients with stage IIIB non-small-cell lung cancer (NSCLC) to investigate whether this is a poor prognostic marker. Methodology\ufeffTo evaluate necrosis on 18F FDG PET/CT, we drew a region of interest (ROI) in the area showing visually very low/or no FDG uptake on PET and PET/CT fusion images. If SUVmax was less than blood pool SUVmax and showed significantly less attenuation [10 to 30 Hounsfield Units (HU)] than surrounding tissue on low-dose correlative CT with non-intravenous contrast, we defined it as necrotic (PETNECROSIS). We evaluated the relationship of SUVmax, tumor size, and PETNECROSIS with Progression-free survival (PFS) using a cox proportional hazard regression model.ResultsPFS analysis was performed in 16 patients treated with standard chemoradiotherapy (CRT) regimen. Tumor size\u2009≤\u200942mm vs\u2009>\u200942mm (p\u2009=\u20090.044, HR: 6.103, 95CI%: 1.053–35.358) and PETNECROSİS presence/absence (p\u2009=\u20090.027, HR: 6.719, 95CI%: 1.245–36.264) were independent predictors for PFS. Patients with tumor size\u2009≤\u200942mm and PETNECROSİS absence were associated with higher 1-year PFS rate than patients with tumor size\u2009>\u200942mm and PETNECROSİS presence (86% vs 63.5% p\u2009=\u20090.005 and 87.5% vs 29%, p\u2009=\u20090.001 respectively).ConclusionPETNECROSİS is helpful to distinguish patients who would suffer worse survival in stage IIIB NSCLC.