Accuracy of Computed Tomography to Predict Extracapsular Spread in p16-Positive Squamous Cell Carcinoma

Objective: To determine the accuracy of pretreatment, contrast-enhanced computed tomography (CT) in the diagnosis of extracapsular spread (ECS) in cervical lymph node metastases from p16-positive head-and-neck squamous cell carcinoma (HNSCC). Study Design: Retrospective observational study. Methods: Sixty-five (n=65) patients diagnosed between 2004 and 2013 with p16-positive HNSCC and with cervical lymph node metastases measuring at least 1 centimeter in diameter on pathological assessment were included. All patients underwent primary surgical treatment. Subjects' preoperative contrast-enhanced neck CT scans were independently assigned a score for the likelihood of ECS (5-point scale) by two board-certified neuroradiologists. Receiver-operating characteristic curves were generated, and optimal sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated for each radiologist. Results: On histological analysis, the majority of patients (58%; 38/65) were found to have ECS, and 29% (19/65) of patients had >= three metastatic lymph nodes. For radiologist 1, PPV and NPV for ECS detection were 72% (95% confidence interval (CI), 53%-87%) and 53% (95% CI, 36%-70%), respectively. For radiologist 2, PPV and NPV for ECS detection were 82% (95% CI, 60 %-95%) and 53% (95% CI, 38%-69%), respectively. Conclusion: CT is not a reliable method for determining the presence of ECS in p16-positive HNSCC patients.