Metabolic tumor burden on postsurgical PET/CT predicts survival of patients with gastric cancer

BACKGROUND: The prognostic value of postoperative (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) to patients with gastric cancer remains unclear. This study aims to investigate the prognostic value of whole body (WB) metabolic tumor burden (MTB(WB)) on postsurgical (18)F-FDG PET/CT to patients with gastric cancer. METHODS: A total of 376 patients with surgeries-confirmed gastric cancer were enrolled. Clinicopathologic information, overall survival (OS) and MTB(WB) parameters on postsurgical PET/CT, in terms of WB maximum standardized uptake value (SUV(WBmax)), WB metabolic tumor volume (MTV(WB)), and WB total lesion glycolysis (TLG(WB)) were collected. In-between differences of patient clinicopathologic characteristics, OS and MTB(WB) measurements were compared using chi-square test, Fisher’s exact test, Student’s t test or the Kaplan-Meier survival analysis. The optimal cutoffs of MTB(WB) measurements were calculated through the receiver operating characteristic (ROC) curve analysis. Univariable and multivariable Cox proportional hazard regression were performed to test the predictive value of the clinicopathologic factors and MTB(WB) measurements to patient survival. RESULTS: The PET-positive patients had significantly decreased OS based on either Kaplan-Meier survival analysis (P < 0.001) or univariable Cox regression (hazard ratio [HR] = 2.850, P < 0.001). In patients with PET-positive tumors, the associations between OS and SUV(WBmax), MTV(WB) and TLG(WB) were significant, both in univariable analysis (P < 0.001, P < 0.001 and P = 0.001, respectively) and in multivariable analysis (P = 0.002, P < 0.001 and P = 0.005, respectively). Patient OS among groups dichotomized by cutoffs of SUV(WBmax) > 8.6, MTV(WB) > 91.5 cm(3), and TLG(WB) > 477.6 cm(3) were significantly different (P = 0.001, P < 0.001 and P = 0.001, respectively). CONCLUSIONS: MTB(WB), in terms of SUV(WBmax), MTV(WB) and TLG(WB), on postsurgical (18)F-FDG PET/CT provides prognostic value to patients with gastric cancer after curative resection.