Abstract
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Objectives: To evaluate the prognostic value of metabolic parameters of primary tumor and metastatic lymph nodes on pretreatment 18F-FDG PET/CT in patients with stage III/IV head and neck squamous cell carcinoma (HNSCC).
Methods: Patients with stage III/IV HNSCC, in whom the maximum standard uptake value (SUVmax) ≥2.5 on pretreatment 18F-FDG PET/CT, were retrospectively included in the study. Five prognostic value of metabolic parameters including maximum standardized uptake value of the primary tumor (SUVT), primary tumor-to-liver uptake ratio (SUVT/L), lymph node (SUVN), lymph node-to-liver uptake ratio (SUVN/L) and lymph node-to-primary tumor uptake ratio (SUVN/T) were assessed for overall survival (OS). Receiver operating characteristic (ROC) curves were used to assess the diagnostic ability of metabolic parameters and to obtain the optimum cut-off value to discriminate the survival of patients. And Kaplan-Meier curves were used to analyze survival outcomes.
Results: Sixty-four patients with HNSCC who underwent pretreatment 18F-FDG PET/CT from January 2010 to December 2016 were analyzed retrospectively. The median follow-up duration was 19 months (range: 2-72 months). Metabolic parameters related to metastatic lymph nodes, including SUVN, SUVN/L and SUVN/T, showed good discrimination in predicting survival (AUC: 0.817, 0.736 and 0.720, P<0.0001, P=0.0021 and 0.0040) with the cut-off value of 14.52, 6.415 and 1.405, respectively. But the discrimination of SUVT and SUVT/L were poor (AUC:0.532 and 0.585, P=0.6767 and 0.2675). Kaplan-Meier curves revealed all the metabolic parameters related to metastatic lymph nodes were important survival predictors (Log-rank P<0.0001, HR 8.210, 95%CI 10.09-90.67 for SUVN; Log-rank P<0.0001, HR 5.440, 95%CI 3.38-21.36 for SUVN/L; Log-rank P=0.0004, HR 4.082, 95%CI 2.144-13.28 for SUVN/T). Conclusions Metabolic parameters related to metastatic lymph nodes, rather than metabolic parameters related to primary tumor, can predict survival effectively in III/IV HNSCC patients.