The correlation between molecular pathological profiles and metabolic parameters of F-FDG PET/CT in patients with gastroesophageal junction cancer.

Objective: The aim of this study was to evaluate PET/FDG metabolic parameters in locally advanced GEJC and correlate it with molecular pathological profiles.

Methods: We retrospectively analyzed data from 66 patients with a histopathological diagnosis of GEJC who had undergone F-FDG PET/CT before surgical resection. Maximum standardized uptake (SUV), mean standardized uptake (SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primary tumor were measured and calculated using the region of interest (ROI) technique. The relationship between metabolic parameters and the Lauren's classification, histologic differentiation, Ki-67 staining and positivity for human epidermal growth factor receptor 2 (HER2), c-Met, and epidermal growth factor receptor (EGFR) were investigated through immunohistochemical (IHC) analyses.

Results: Of the total 66 patients, significant differences were observed between intestinal and non-intestinal (mixed and diffuse) adenocarcinomas in SUV (8.23 ± 2.83 vs. 6.29 ± 2.41, P = 0.008), SUV (4.85 ± 1.47 vs. 3.93 ± 1.22, P = 0.017), MTV (24.96 cm vs. 8.90 cm; P = 0.004), and TLG (97.38 cm vs. 37.09 cm, P = 0.005) values. SUV, MTV, and TLG of moderately differentiated adenocarcinomas were significantly higher than those of the poorly differentiated ones. SUV was significantly higher in tissues with a higher Ki-67 index or in the c-MET-negative group (P = 0.045, P = 0.036). No significant correlation was found between metabolic parameters and the expression of HER2 or EGFR in GEJC.

Conclusion: F-FDG PET/CT may be useful for predicting the molecular pathological profiles of GEJC and for determining appropriate therapeutic strategy.