Potential values of metabolic tumor volume and heterogeneity measured with ¹⁸F-FDG PET/CT pretreatment to evaluate local control for esophageal squamous cell carcinoma treated with nonsurgical therapy.

Objectives: The aim of the study was to evaluate the predictive value of fluorine-18 fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) pretreatment on local control (LC) and survival after radical radiotherapy or chemoradiotherapy in patients with locally advanced esophageal squamous cell carcinoma (SCC) and to discuss its potential value for establishing optimal radiation treatment plans.
Methods: Fifty-eight patients with pathologically proven esophageal SCC who underwent ¹⁸F-FDG PET/CT pretreatment in our center were retrospectively reviewed. We examined the correlation between the PET parameters of primary tumors and LC and overall survival. The coefficient of variation was used to estimate the ¹⁸F-FDG uptake in heterogeneity.
Results: The mean duration of follow-up for surviving patients was 38 months, and 36 patients died because of tumor recurrence or other diseases. The rates of 3-year overall survival and LC were 40.4 and 50.4%, respectively. Multivariate analysis of LC revealed that metabolic tumor volume (MTV) greater than 16.08 ml was the only predictor of outcome, with a lower 3-year LC (P=0.017, hazard ratio: 1.608, 95% confidence interval: 1.090-2.371). The coefficient of variations of their primary lesion were higher compared with those of patients who had smaller MTVs.
Conclusion: In this study, MTV assessed by PET/CT might be an adverse factor for predicting LC in esophageal SCC. For those with higher MTVs, higher intratumor heterogeneity suggests that irradiation may need to be boosted in stable high-uptake regions to improve LC. These results need to be prospectively validated in larger cohorts.