Clinical utility of delayed regional PET/CT after water distension for evaluating locoregional disease of gastric cancer

Objectives The aim of this study was to assess the utility of delayed regional F-18 FDG PET/CT after water gastric distension to detect the locoregional disease in the gastric cancer.

Methods Ninety-six patients (59.0 ± 11.8 years) with pathologically proven stomach cancer were enrolled. Sixty minutes after ¹⁸F-FDG injection, whole body ¹⁸F-FDG PET/CT (WB PET) with water gastric dilatation was performed. Regional gastric distant PET (regional PET) was followed 120 min post FDG injection. The detectability for loco-regional lesions were compared between WB- and regional PET.

Results Primary tumor sensitivity of WB PET (63.5%) was improved by regional PET (84.4%, p<0.0001). Of 96 stomach cancer patients, 33 patients had pathologically proven metastatic lymph nodes. In comparison with WB PET, regional PET had significantly improved sensitivity (42.4% vs. 60.6%, p = 0.0313) and equivocal specificity (88.9 vs. 85.7%, p = 0.6875) for lymph node metastasis. Higher SUVmax ratio of the primary tumor to adjacent gastric wall (SUVmax ratio) on WB PET denoted shorter progression free survival in gastric cancer (HR 1.2614; p = 0.0129).

Conclusions Two hour delayed regional PET after water gastric distension has improved accuracy for evaluating locoregional disease of gastric cancer, however, SUVmax ratio on WB PET is the only independent factor to predict progression free survival. Further prospective studies are needed to confirm our results.

Research Support this research was funded by National Research Foundation (2012R1A1A1012913 and 2012M3A9B6055379) of south Korea.