18F-FDG-PET/CT for the assessment of the contralateral neck in patients with head and neck squamous cell carcinoma.

ABSTRACT

OBJECTIVES/HYPOTHESIS: The aim was to compare the value of 18-Fluoro-Deoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) regarding contralateral lymph node (LN) metastasis in the neck. STUDY DESIGN: Retrospective analysis of 61 patients staged by 18F-FDG-PET/CT. METHODS: Cytology/histology served as a reference standard. Further, metabolic midline invasion (MI) of the primary tumor and the presence of bilateral LN metastases were assessed. RESULTS: A true positive rate in the ipsilateral neck of 80% versus 65% in the contralateral neck was found (P = 0.067). Median-standardized uptake value (SUV)-max for suspicious LN ipsilaterally was 7.6 versus 5.8 contralaterally (P = 0.038). There was no positive correlation between metabolic MI and bilateral metastasis (P = 0.82). CONCLUSIONS: The rate of true positive detected LN by 18F-FDG-PET/CT is less on the contralateral neck side; therefore, all suspicious LNs should be verified by cytology. A high SUV in the contralateral neck suggests metastatic disease regardless of nodal size. Metabolic MI needs to be addressed carefully as it was not predictive for bilateral LN involvement. LEVEL OF EVIDENCE 4.