Dynamic whole‑body positron emission tomography/computed tomography for predicting treatment response to chemoradiotherapy in patients with esophageal cancer

Most positron emission tomography/computed tomography (PET/CT) studies are based on static whole-body images; however, dynamic whole-body PET/CT (DW-PET/CT) enables quantification of tissue glucose metabolism dynamics. The aim of the present study was to investigate whether DW-PET/CT can predict treatment response in patients with esophageal squamous cell carcinoma (ESCC) treated with chemoradiotherapy (CRT). A total of 56 patients with ESCC who underwent pretreatment DW-PET/CT were evaluated. DW-PET/CT parameters of the main tumor, including the Patlak slope (PS, absolute rate of tracer consumption) and Patlak intercept (PI, degree of tracer perfusion in the tumor), were calculated using four DW-PET/CT image series acquired every 5 min starting 60 min after injection of ¹⁸F-fluorodeoxyglucose. The maximum standardized uptake value (SUVmax) of the tumor was also measured 60 min after tracer injection. The relationships of these PET-derived parameters with treatment response were analyzed using area under the receiver operating characteristic curve (AUC) analyses. The treatment responder group included 38 patients, whereas there were 18 non-responders according to the Response Evaluation Criteria in Solid Tumors. Tumors of responders showed significantly higher SUVmax, PS and PI than those of non-responders (P=0.04, 0.0012 and 0.0018, respectively). PS and PI demonstrated good performance in predicting treatment response with AUC values of 0.71 and 0.76, respectively, whereas the SUVmax showed a poor performance with an AUC value of 0.67. The tumor contraction rate during CRT was significantly and positively correlated with PS and PI (R=0.60, P=0.0061 and R=0.54, P=0.0265, respectively). In conclusion, DW-PET/CT may enable pretreatment prediction of the CRT treatment response in patients with ESCC.