18F-FDG PET/CT in gastro-oesophageal cancer: correlations between Partial Volume Corrected Body-Weight Standardized between Partial Volume Corrected Body-Weight Standardized primitives

AIM To assess the diagnostic value of 18F-FDG PVC-SUVBW as possible biomarker in gastric cancer (GC). MATERIALS AND METHODS 49 biopsy-proven gastrooesophageal cancer patients were enrolled in an integrated protocol. Patients underwent a basal 18F-FDG PET/CT study. 18F-FDG PET/CT specificity was assessed. Averaged PVC-SUVBW was calculated on primitive gastric lesions [1]. Correlation tests (Mann-Whitney and Kruskal Wallis tests for univariate analysis and hierarchical clustering for multivariate analysis) were performed to evaluate the relationships between 18F-FDG PVC-SUVBW and histotype and grade of gastric malignancy evaluated by biopsy. RESULTS: 18F-FDG PET/CT was able to detect gastric cancer with a specificity of 82%. In 9 biopsy-proven GC, 18F-FDG PET/CT images were classified as negative, showing no 18F-FDG uptake in the GC primitive lesions. Signet ring cell histology showed a lower 18F-FDG PVC-SUVBW compared to squamous cell carcinomas and to other adenocarcinoma subtypes (PVC-SUVBW: 5.57±3.22 g/cc vs 9.90 ± 1.91g/cc vs 9.32 ± 4.26g/cc; p=0.05). No correlations were found between tumor grading and 18F-FDG PVC-SUVBW. Multivariate analysis showed that poorly differentiated signet ring cell carcinomas were significantly associated with 18F-FDG PVC-SUVBW smaller than 6.25 g/cc (p<0.05). CONCLUSIONS Confirming literature results, 18F-FDG PET/CT shouldn't be considered the gold standard modality to evaluate gastric primitive lesions [2]. However, these preliminary results suggest that the 18F-FDG PVC-SUVBW is a valuable biomarker to assess the biological characteristic of GC in vivo. REFERENCES [1] F. Gallivanone, et al. (2011) "PVE correction in PET-CT whole-body oncological studies from PVE-affected images", IEEE Trans Nucl Sci, vol. 58(3), pp. 736-747. [2] Podoloff DA et al. (2009) NCCN task force: clinical utility of PET in a variety of tumor types. J Natl Compr Canc Netw. 7(Suppl2):S1-26.