Additional diagnostic value of (18)F-FDG PET-CT in detecting retropharyngeal nodal metastases.

Abstract

This study investigated whether preoperative (18)fluorine-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) scanning improved the diagnosis of retropharyngeal lymph node (RPLN) metastasis in patients with head and neck squamous cell carcinoma (HNSCC) relative to conventional imaging alone. Case series with chart review. University hospital cancer center. Sixty-three patients with HNSCC underwent RPLN dissection in accordance with our indications and were subsequently divided into two groups: CT/magnetic resonance imaging (MRI) only (group A, n = 33) and CT/MRI with PET-CT (group B, n = 30). The preoperative radiological findings of each group were compared with the RPLN histopathologic findings, which served as the standard of reference. RPLN metastasis was confirmed histopathologically in 17 of 63 patients (27.0%): eight from group A and nine from group B. With the additional use of PET-CT in group B, the sensitivity (88.9%), specificity (85.7%), and accuracy (86.7%) were higher than the respective values in group A (62.5%, 60.0%, and 60.6%). The positive and negative predictive values for group B (72.7% and 94.7%, respectively) were also higher than those for group A (33.3% and 83.3%, respectively). False-positive results were obtained in 10 patients from group A and three patients from B; false-negative findings occurred in three patients from group A and one patient from group B. The predictive power of the radiological findings was statistically significant in group B (P = 0.0017), with an odds ratio of 47.987 (95% confidence interval, 4.3-535.0). (18)F-FDG PET-CT, when used in combination with CT/MRI, increases diagnostic efficacy in the detection of RPLN metastases and may therefore be useful in screening high-risk patients.