[18F] Fluorodeoxyglucose PET/CT and prediction of histopathological response to neoadjuvant chemotherapy for adenocarcinoma of the oesophagus and oesophagogastric junction

BackgroundThe aim of this prospective study was to assess whether [F-18]fluorodeoxyglucose PET can be used to predict histopathological response early in the course of neoadjuvant chemotherapy in patients with adenocarcinoma of the oesophagus and oesophagogastric junction. MethodsFollowing the PET response criteria in solid tumours (PERCIST 1.0) as a standardized method for semiquantitative assessment of metabolic response, FDG-PET/CT was performed before (PET1) and after (PET2) initiation of the first cycle of chemotherapy. The relative changes in the peak standardized uptake value (SUL) and total lesion glycolysis (TLG) between PET1 and PET2 were correlated with histopathological response, defined as less than 50 per cent viable tumour cells in the resection specimen. A receiver operating characteristic (ROC) curve analysis was used to identify the optimal cut-off value with the highest accuracy of histopathological response prediction. ResultsPET2 was performed a median of 16 (range 12-22) days after the start of chemotherapy. Some 27 of 90 patients who underwent surgery had a histopathological response. There was no association between the median SUL or median TLG and the histopathological response. A post hoc analysis in 47 patients with PET2 performed 16days or less after the start of chemotherapy showed that TLG, but not SUL, was associated with the histopathological response (P=0009). The optimal cut-off value of TLG was 66 per cent or more. ConclusionFDG-PET/CT after the first cycle of chemotherapy does not predict histopathological response in patients with adenocarcinoma of the oesophagus and oesophagogastric junction. Of no use