Radiographic Imaging Does Not Reliably Predict Macroscopic Extranodal Extension in Human Papilloma Virus-Associated Oropharyngeal Cancer.

BACKGROUND: Radiographic concern for lymphatic extranodal extension (ENE) impacts upfront management decisions for patients with human papilloma virus (HPV) oropharyngeal squamous cell carcinoma (OPSCC). Therefore, we set out to evaluate the accuracy of preoperative contrast-enhanced computed tomography (CECT) to predict major ENE (> 2 mm).

METHODS: Twenty-seven consecutive patients with HPV-associated OPSCC who presented at our institutional multidisciplinary tumor board were staged radiographically with positron emission tomography (PET/CT) and CECT, and underwent primary transoral robotic resection and neck dissection. CECT imaging results were correlated with pathologic ENE (pENE).

RESULTS: CECT specificity for all pENE was 69 and 75% for radiologist 1 and 2, respectively. For pENE > 2 mm, the sensitivities were 88 and 100%, but specificities were 52.6 and 63.2%. Positive predictive values (PPV) were 43.8 and 53.3%; negative predictive values were 90.9 and 100%. On logistic regression analysis, only size ≥3 cm (OR 4.7-5.4, p < 0.02, 95% CI 1.3-44.0) demonstrated significant correlation with major ENE > 2 mm.

CONCLUSIONS: Preoperative imaging for HPV-associated OPSCC had a PPV for pENE > 2 mm of 44-55%, based on any interruption in the capsule or invasion into the perinodal fat. The PPV is low and equipoise in treatment decision making for patients with HPV-associated OPSCC may require other imaging characteristics.