Clinical utility of 18F-FDG PET-CT and CT/MRI for detecting nodal metastasis in oropharyngeal squamous cell carcinoma patients with N0 neck

Abstract

PURPOSE: To investigate the clinical utility of [18F]fluorodeoxyglucose positron emission tomography-computed tomography ([18F]FDG PET-CT) compared with CT or magnetic resonance imaging (MRI) for detecting nodal metastasis in oropharyngeal squamous cell carcinoma (SCC) patients with N0 neck and to investigate whether various pretreatment imaging modalities support the rationale for elective neck treatment in patients with oropharyngeal SCC.MATERIALS AND METHODS: A total of 49 patients with clinically negative (N0) neck (42 men and 7 women; average age, 59.1 years) underwent primary tumor resection and neck dissection as a primary treatment. All patients were preoperatively evaluated with PET-CT and CT/MRI, and the diagnostic accuracy of each imaging modality was assessed by correlation with histopathologic results of the surgical specimen.RESULTS: Twenty-five (51.0%) of our 49 patients were found to have neck metastases. On a level-by-level analysis, the sensitivity of PET-CT, CT/MRI, and a combination of PET-CT and CT/MRI was 54.6%, 54.6%, and 60.6%, respectively, at all neck levels. False negative results were found in 15 (9.3%) of 162 neck levels on each of PET-CT and CT/MRI. On a patient-by-patient analysis, the sensitivity of PET-CT for neck metastases was 64.0% and increased slightly to 68.0% after combined interpretation with CT/MRI.CONCLUSION: Addition of PET-CT examination to CT/MRI was found to be helpful for detecting nodal metastasis in the preoperative evaluation of patients with oropharyngeal SCC and N0 neck. However, PET-CT with CT/MRI showed still low sensitivity in the assessment of nodal metastasis in clinically N0 neck; therefore, preoperative imaging modalities may not abrogate the need for elective neck management in these patients.