Prognostic significance of 18F-Fluorodeoxyglucose positron-emission tomography parameters in patients with biliary tract cancers: a meta-analysis.

ABSTRACT

BACKGROUND AND OBJECTIVE: Numerous previous studies have assessed the prognostic role of 18F-fluorodeoxyglucose positron-emission tomography (18F FDG PET) in patients with biliary tract cancer (BTC), but those results were inconsistent. The present study aims to determine the predictive value of 18F FDG PET in BTC patients via a meta-analysis. METHODS: The underlying studies related to 18F FDG PET and BTC patients` outcomes were searched and identified in the online databases. The interested parameters include total lesion glycolysis (TLG), metabolic tumor volume (MTV), primary tumor and metastatic lymph node (LN) maximum standardized uptake value (SUVmax), as well as change of SUVmax (ΔSUVmax) during treatment. Overall survival (OS), disease-free survival (DFS), and progression-free survival (PFS) were considered as the primary endpoints. Hazard ratio (HR) and corresponding 95% confidence intervals (CIs) were defined as the effective measure and calculated by a pooled analysis. Publication bias was assessed by funnel plot, Bagg's and Egger's tests. RESULTS: Totally, 23 studies involving 1478 patients were included in the present meta-analysis. After a pooled analysis, it revealed that a high SUVmax was significantly associated with a poor OS (HR2.07, 95%CI 1.74-2.46, P = 0.000) and DFS (HR 2.28, 95%CI 1.53-3.41, P = 0.000). In addition, an increased TLG level contributed to a shorter OS (HR1.91, 95%CI 1.26-2.90, P = 0.002) and DFS (HR 4.34, 95%CI 1.42-13.27, P = 0.01). Moreover, we confirmed that an elevated MTV was significantly associated with increased mortality (HR2.04, 95%CI1.26-3.31, P = 0.004) and disease relapse (HR 3.88, 95%CI1.25-12.09, P = 0.019) risks. Besides, the present study uncovered that increased ΔSUVmax could predict poor OS (HR1.26, 95%CI1.06-1.50, P = 0.008) instead of PFS (HR 1.96, 95%CI 0.82-4.72, P = 0.280). Lastly, we found that LN SUVmax did not link to OS (HR 1.49, 95%CI 0.83-2.68, P = 0.178). No obvious publication bias was detected in the present study. CONCLUSION: 18F FDG PET parameters, including SUVmax, TLG, MTV, and ΔSUVmax, could be applied as convenient and reliable factors for predicting BTC patients` outcomes.