Cystic nodal metastasis in patients with oropharyngeal squamous cell carcinoma receiving chemoradiotherapy: Relationship with human papillomavirus status and failure patterns

Objectives: We investigated the relationships of cystic nodal metastasis, human papillomavirus (HPV) status, and treatment failure patterns in patients with oropharyngeal squamous cell carcinoma (OPSCC) treated with chemoradiotherapy. Methods: We retrospectively reviewed pretreatment MRI and clinical courses of patients with OPSCC whose tumors were tested for HPV-induced p16 expression via immunohistochemistry and who completed chemoradiotherapy. Cervical cystic nodal metastasis and necrotic nodal metastasis were classified on MRI. Results: Of 98 patients eligible for analysis, 33 were p16-positive. Cystic nodal metastasis was significantly more prevalent in p16-positive than in p16-negative patients (39.4% versus 18.5%, respectively; p = 0.025). Necrotic nodal metastasis was significantly more prevalent in p16-negative than in p16-positive patients (73.8% versus 51.5%, respectively; p = 0.027). On multivariate analysis, necrotic nodal metastasis (odds ratio [OR] = 7.310, p = 0.011) was an independent predictor of regional failure, while advanced nodal stage (OR = 4.119, p = 0.022) and cystic nodal metastases (OR = 0.087, p = 0.026) were independent positive and negative predictors of distant failure, respectively. Conclusions: Cervical cystic and necrotic nodal metastases are associated with HPV-induced p16-positive and p16-negative OPSCC, respectively. Patients with necrotic nodal metastasis at presentation have an increased risk of regional failure. Distant failure is directly and inversely correlated with advanced nodal stage and cystic nodal metastasis, respectively.