Prospective study of [18F] fluorodeoxyglucose positron emission tomography and computed tomography and magnetic resonance imaging in oral cavity squamous cell carcinoma with palpably negative neck

Purpose To assess the clinical usefulness of (F-18]fluorodeoxyglucose positron emission tomography ([F-18]FDG PET) as well as computed tomography (CT) or magnetic resonance imaging (MRI) in oral squamous cell carcinoma (SCC) patients with palpably negative neck. Patients and Methods In total, 134 oral SCC patients with palpably negative neck were prospectively evaluated with [F-18]FDG PET, CT/MRI, and their visual correlation. Histopathologic analysis was used as the gold standard for assessment of these imaging techniques. Results Thirty-five (26.1 %) of our 134 patients were found to have neck metastases. On a level-by-level basis, the sensitivity of [F-18]FDG PET for nodal metastases was two-fold higher than that of CT/MRI (41.2% v 21.6%, respectively, P =.021). Visual correlation of [F-18]FDG PET and CT/MRI yielded slightly higher sensitivity and specificity than [F-18]FDG PET alone (47.1 % v 41.2%, P =.25; 98.0% v 96.8%, P =.125, respectively). On a patient-by-patient basis, the sensitivity of [F-18]FDG PET for neck metastases was 51.4% and increased to 57.1% after visual correlation with CT/MRI. The probabilities of occult neck metastasis after using [F-18]FDG PET were 6.7% in T1 tumors, 10.8% in T2 tumors, 13.3% in T3 tumors, and 25% in T4 tumors and decreased to 3.3% in T1 tumors and to 9.2% in T2 tumors after visual correlation with CT/MRI. Conclusion [F-18]FDG PET was superior to CT/MRI for detecting palpably occult neck metastasis of oral SCC. Because [F-18]FDG PET could reduce the probability of occult neck metastasis to less than 15% in T1 to T3 tumors, it should be indicated for evaluation of these subpopulations.