Investigating the Reliability of Fluorodeoxyglucose 18 Positive Emission Tomography-Computed Tomography Detection of Regional Lymph Node Metastasis in Head and Neck Malignancy.

Purpose: This study investigated whether fluorodeoxyglucose 18 positive emission tomography (PET)-computed tomography (CT) may be relied on to direct surgical management of the neck in patients with head and neck cancer by assessing the accuracy with which it is able to detect the presence and location of regional lymph node metastasis compared with histologic examination.

Patients And Methods: This retrospective study reviewed consecutive cases of head and neck cancer in which patients received a PET-CT scan within 3 weeks of undergoing a neck dissection performed by the Ascension Macomb-Oakland oral and maxillofacial surgery residency program from July 2013 through July 2018. Neck dissection specimens were orientated by the surgeon according to neck level and submitted for histopathologic examination. These histopathologic results served as the standard reference with which preoperative PET-CT results were compared.

Results: A total of 156 cases were reviewed in this study, 84 of which were included for data analysis. PET-CT exhibited an overall sensitivity of 68.9% and specificity of 61.5% in detecting regional lymph node metastasis (positive predictive value, 67.4%; negative predictive value, 63.2%). PET-CT showed a sensitivity of 71.4% and specificity of 75.0% for 34 cases involving pT1 lesions (positive predictive value, 66.7%; negative predictive value, 79.0%). Of 25 true-positive PET-CT scans correctly correlating with pN neck specimens, 16 (64%) were inaccurate in identifying the proper levels of metastatic disease identified by histopathologic assessment. These scans flagged 44 neck levels positive for disease, 18 (41%) of which were histologically proven false positive. Of the 48 neck levels in these cases confirmed positive for metastasis by histopathologic assessment, 22 (46%) failed detection by what would otherwise be considered true-positive PET-CT scans.

Conclusions: The results of this study suggest that PET-CT is unable to adequately detect the overall presence or precise location of metastatic disease in the neck and so cannot be relied on to direct surgical management of the neck in patients with head and neck cancer.