18F-FDG PET/CT Versus Contrast-Enhanced CT for Staging and Prognostic Prediction in Patients With Salivary Gland Carcinomas

Salivary gland carcinoma (SGC) is rare tumor with various histological type and metastatic potential. Pretreatment detection of metastases can contribute to planning the appropriate treatment of SGC. Therefore, the present study evaluated the utility of F-FDG PET/CT versus contrast-enhanced CT for detection of metastases and prediction of outcomes in SGC patients.Sixty-seven consecutive SGC patients who were prospectively evaluated by F-FDG PET/CT and contrast-enhanced CT and subsequently underwent surgery with or without postoperative radiotherapy/chemoradiotherapy were included. The diagnostic values of both imaging modalities for detection of metastatic diseases were compared with McNemar test and logistic regression using generalized estimating equations. Cox proportional hazard modeling was used to assess the prognostic values of the quantitative metabolic measurements detected by F-FDG PET/CT and of other clinical factors.Among 67 SGC patients, 17 (25.4%) had cervical metastasis, and 4 (6%) had distant metastasis at initial staging. The sensitivity of F-FDG PET/CT for detection of cervical metastasis was significantly higher than those of CT (P0.05), and those of F-FDG PET/CT and CT for detection of distant metastasis did not differ (P0.5). Regional and distant site metastases were most reliably predicted by high-grade pathological analysis (P0.05). Extranodal extension and metabolic tumor volume measured by F-FDG PET/CT were independent predictors of progression-free survival and overall survival (all P0.05).In SGC patients, F-FDG PET/CT detected metastatic diseases with high sensitivity and specificity, and metabolic tumor volumes helped to predict survival outcomes.