18F-FDG PET/CT of advanced gastric carcinoma and association of HER2 expression with standardized uptake value

Objective(s): expression of her2 in gastric carcinoma has direct prognostic and therapeutic implications in patient management. the aim of this study is to determine whether a relationship exists between standardized uptake value (suv) and expression of her2 in advanced gastric carcinoma. methods: we analyzed the 18f-fdg pet/ct results of 109 patients that underwent gastrectomy for advanced gastric carcinoma. the 18f-fdg pet/ct imaging was requested at the initial staging before surgery. the examinations were evaluated semi-quantitatively, with calculation of maximum standardized uptake values (suvmax). the clinicopathologic factors, including her2 overexpression, were determined from tissue obtained from the primary tumor. metabolic and clincopathologic parameters were correlated using a t-test, one way anova and chi-square test. results: immunohistochemically, 26 patients (23.8%) showed her2 overexpression. this overexpression was significantly associated with high suv level (p=0.02). the suv level was significantly correlated with tumor size (p=0.02) and differentiation (p < 0.001), and lauren histologic type (p=0.04). multivariate analysis showed her2 overexpression, large tumor size, and differentiation (p=0.022, p=0.002, p < 0.001) were significantly correlated with the high level of suv in advanced gastric carcinoma. no association was found between suv and t stage and lymph node metastasis. a receiver-operating characteristic curve demonstrated a suvmax of 3.5 to be the optimal cutoff for predicting her2 overexpression (sensitivity; 76.9%, specificity; 60.2%). conclusion: an association exists between high suv and her2 overexpression and 18f-fdg pet/ct could be a useful tool to predict the biological characteristics of gastric carcinoma.