Metabolic information on staging FDG-PET-CT as a prognostic tool in the evaluation of 97 patients with gastric cancer

Background and objective: Gastric cancer remains a leading cause of malignancy-related mortality. Many patients with locally advanced disease succumb despite peri-operative chemotherapy and the survival benefit of chemotherapy for advanced disease is modest, suggesting that current staging is imperfect. The role of fluorine-18-2-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) in the staging of gastric cancer remains to be determined. This study aimed to determine, and compare with computerized tomography (CT), the association between FDG-PET uptake in the primary tumour and regional lymph nodes, and overall survival in patients with all stage gastric cancer. Methods: Patients with histologically confirmed gastric cancer (any stage) who, at diagnosis, had received a staging FDG-PET-CT at our institution between 2006 and 2011 were included. Records were retrospectively analysed. Patients with >50 % of tumour above the gastro-oesophageal junction or an active second malignancy were excluded. Results: 97 patients were included in the analysis. Surgery with curative intent was performed in 68 patients. In univariate analysis, an association with overall survival was seen in patients who had FDG-PET-positive primary tumours (hazard ratio (HR) for death 3.33, 95 % confidence interval (95 % CI) 1.63-6.80, p = 0.001). FDG-PET lymph node positive (vs node negativity) was associated with inferior overall survival (HR 8.66, 95 % CI 4.59-16.37, p < 0.0001), and remained an independent predictor in the multivariate analysis. In contrast, positive lymphadenopathy identified on CT was not associated with overall survival (HR 1.34, 95 % CI 0.79-2.29, p = 0.82). Conclusion: FDG-PET-positive tumours are associated with an inferior overall survival. In contrast to CT, FDG-PET-positive lymphadenopathy is associated with a decreased overall survival.