Utility of FDG PET in patients with squamous cell carcinomas of the oral cavity

The utility of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in oral cavity cancer has received little attention in a clinician's perspective. We systematically evaluated the clinical roles of FDG PET in patients with oral cavity squamous cell carcinomas (SCCs).

Between August 2001 and February 2005, 82 new patients with resectable oral cavity SCCs underwent CT/MRI and FDG PET at initial staging and follow-up. The sensitivity and specificity of CT/MRI and FDG PET for neck metastases were compared with histopathologic reference of 67 patients who underwent neck dissection. The relationships between the maximal standardized uptake value (SUV) of primary tumors and clinicopathologic parameters, such as gender, age, tumor thickness, local invasiveness, T and N categories, tumor-node-metastasis stage, and histological grade, as well as with disease-free survival (DFS), were assessed.

FDG PET was more sensitive than CT/MRI for detecting cervical metastases on a level-by-level basis (38/43 vs. 28/43; P=0.002). Age, T and N categories, tumor thickness (>8mm) and SUV (>5.0) were also significant variables of 3-year DFS in univariate analysis. T category was an independent determinant of DFS in multivariate analysis (P<0.05). During a mean follow-up of 36 months, FDG PET correctly diagnosed locoregional recurrences in 20 patients, distant metastases in six and second cancers in five.

FDG PET may have potential roles in initial staging, survival prediction, and the detection of recurrences and second cancers.