Risk Stratification of Metastatic Neck Nodes by CT and PET in Patients with Head and Neck Cancer Receiving Definitive Radiotherapy

The aim of this study was to investigate the prognostic impact of CT and F-18-FDG PET/CT on the outcome of metastatic neck node (MNN) in patients with head and neck cancer receiving definitive radiotherapy or chemoradiotherapy. Methods: This patient-based study included 91 patients diagnosed with pharyngeal cancers with MNN (N1, 15; N2, 70; N3, 6). All had pretreatment CT and PET/CT before definitive chemoradiotherapy/radiotherapy. Parameters of MNNs for each patient, including maximal diameter, nodal volume, radiologic central necrosis, maximum standardized uptake value, metabolic tumor volume, and total lesion glycolysis (TLG), were retrieved for the analysis. Nodal relapse-free survival (NRFS) and survivals were calculated using the Kaplan-Meier method. Independent predictors were identified using Cox regression analysis. Results: After a median follow-up of 18 mo, 64 patients remained nodal relapse-free, and 27 experienced neck recurrence. Multivariate analysis showed that the application of 40% of the maximal uptake of nodal TLG (N-TLG40%) 38 g or greater (P = 0.03; hazard ratio, 2.63; 95% confidence interval, 1.10-6.30) and radiologic necrosis on CT scan (P = 0.001; hazard ratio, 10.99; 95% confidence interval, 2.56-47.62) were 2 adverse features for NRFS. Patients who had an N-TLG40% 38 g or greater and central radiologic necrosis had a significantly inferior 2-y NRFS (53% vs. 77% and 45% vs. 95%, respectively). Conclusion: The outcome of MNNs in patients with head and neck cancer receiving chemoradiotherapy/radiotherapy can be predicted according to radiologic necrosis and N-TLG40% value. The 2 adverse features should be validated in future trials. In this way, patients can be treated alternatively or aggressively.