Impact of whole body positron emission tomography on initial staging and therapy in patients with squamous cell carcinoma of the oral cavity.

The aim of this study is to evaluate the additional clinical information provided by whole body positron emission tomography (PET) with fluorodeoxyglucose (FDG) for initial staging of patients with squamous cell carcinoma (SCC) of the oral cavity. PET scans from the head to the pelvic floor of 34 consecutive patients (22 male, 12 female; mean age 71 years) with histologically confirmed SCC of the oral cavity were retrospectively evaluated. Clinical information including CT of the head and neck and chest X-Ray or chest CT was compared with information on nodal involvement and distant metastases or secondary tumours obtained with PET. The primary tumour was identified with PET in 33 of 34 patients (97%). In 27 Patients (81%) the clinical N-stage was confirmed with PET. In two Patients (6%) additional pathologic loco-regional lymph nodes were found. In five patients more lymph nodes were identified with CT. Distant lesions were seen with PET imaging in bone, lung, mediastinum, liver and colon. In three patients (6%) distant metastases were correctly identified. In another four patients (12%) a secondary cancer was detected. One false positive finding was described with PET. In five of 34 patients (15%) the additional findings as revealed with PET lead to a change of treatment. Whole body PET provides relevant additional information to a standard clinical staging procedure in patients with oral cavity SCC. The detection of distant metastases and secondary primary tumours can have a great impact on patient management.