Cervical nodal metastases from head and neck squamous cell carcinoma: MRI criteria for treatment assessment.

BACKGROUND The purpose of this study was to assess MRI criteria for detecting residual malignant head and neck squamous cell carcinoma (HNSCC) nodes after chemoradiotherapy (CRT). METHODS One hundred and six metastatic nodes were assessed 6 weeks posttreatment by MRI for necrosis, extranodal neoplastic spread (ENS), size, and percentage of size change. Size measurements were reanalyzed after dividing posttreatment nodes into "discrete solid," "discrete necrotic," and "indiscrete" groups. Results were correlated with nodal response at 2 years. RESULTS Eighty-three residual nodes were benign and 23 were malignant. Significant predictors of outcome were percentage of change in solid volume (total-necrotic volume; p = .0002) for all posttreatment nodes and percentage of change in total volume for "discrete solid" posttreatment nodes (p = .0003), the latter showing a ≤78% reduction of predicted residual malignant nodes with a negative predictive value (NPV) of 98.2% and positive predictive value (PPV) of 60%. Necrosis, ENS, and size of "discrete necrotic" and "indiscrete" nodes were not significant criteria. CONCLUSION Necrosis and ENS were inaccurate criteria for residual malignant nodes and hindered the accuracy of size measurements. © 2016 Wiley Periodicals, Inc. Head Neck 38: E1598-E1604, 2016.