The prognostic significance of intratumoral heterogeneity of 18F-FDG uptake in patients with oral cavity squamous cell carcinoma

Purpose This study aimed to evaluate the prognostic significance of two major indices of intratumoral heterogeneity of 18F-fluorodeoxyglucose uptake by positron emission tomography (PET)/computed tomography (CT), namely heterogeneity index (HI) and heterogeneity factor (HF), in patients with oral squamous cell carcinoma. Methods We performed a retrospective analysis of 62 patients who underwent resective surgery. HI, HF, maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were obtained from pretreatment PET. HI was obtained by dividing SUVmax by SUVmean for the primary lesion; HF was obtained by taking the derivative (dV/dT) of the volume-threshold function from 30 to 70%. Univariate and multivariate analyses for the overall survival (OS) and disease-free survival (DFS) were performed using PET and clinicopathological parameters. Results Univariate and multivariate analyses of OS revealed that higher HI levels (threshold for the SUVmean is 30% of the SUVmax) were associated with poorer OS [hazard ratio (HR) = 11.57; 95% confidence interval (CI) = 1.45–92.28; P = 0.021]. Moreover, univariate and multivariate analyses of DFS revealed that higher TLG levels (threshold for the MTV and SUVmean is 4.0 of the SUV) were associated with poorer DFS (HR = 14.48; 95% CI = 1.27–164.78; P = 0.031). Conclusions HI and TLG may be statistically significant prognostic factors for OS and DFS, respectively.