Heterogeneity of Glycolytic Phenotype Determined by [sup.18]F-FDG PET/CT Using Coefficient of Variation in Patients with Advanced Non-Small Cell Lung Cancer

We investigated the role of Coefficient of Variation (CoV), a first-order texture parameter derived from [sup.18]F-FDG PET/CT, in the prognosis of Non-Small Cell Lung Cancer (NSCLC) patients. Eighty-four patients with advanced NSCLC who underwent [sup.18]F-FDG PET/CT before therapy were retrospectively studied. SUVmax, SUVmean, CoV, total Metabolic Tumor Volume (MTV[sub.TOT]) and whole-body Total Lesion Glycolysis (TLG[sub.WB]) were determined by an automated contouring program (SUV threshold at 2.5). We analyzed 194 lesions: primary tumors (n = 84), regional (n = 48) and non-regional (n = 17) lymph nodes and metastases in liver (n = 9), bone (n = 23) and other sites (n = 13); average CoVs were 0.36 ± 0.13, 0.36 ± 0.14, 0.42 ± 0.18, 0.30 ± 0.14, 0.37 ± 0.17, 0.34 ± 0.13, respectively. No significant differences were found between the CoV values among the different lesion categories. Survival analysis included age, gender, histology, stage, MTV[sub.TOT], TLG[sub.WB] and imaging parameters derived from primary tumors. At univariate analysis, CoV (p = 0.0184), MTV[sub.TOT] (p = 0.0050), TLG[sub.WB] (p = 0.0108) and stage (p = 0.0041) predicted Overall Survival (OS). At multivariate analysis, age, CoV, MTV[sub.TOT] and stage were retained in the model (p = 0.0001). Patients with CoV > 0.38 had significantly better OS than those with CoV ≤ 0.38 (p = 0.0143). Patients with MTV[sub.TOT] ≤ 89.5 mL had higher OS than those with MTV[sub.TOT] > 89.5 mL (p = 0.0063). Combining CoV and MTV[sub.TOT], patients with CoV ≤ 0.38 and MTV[sub.TOT] > 89.5 mL had the worst prognosis. CoV, by reflecting the heterogeneity of glycolytic phenotype, can predict clinical outcomes in NSCLC patients.