Evaluation of Lymph Node Metastasis in Oropharyngeal Squamous Cell Carcinoma

Abstract

Objectives: (1) Examine the association between histopathologic variables and neck metastasis. (2) Analyze the effect of human papillomavirus (HPV) status on lymph node (LN) metastasis. Methods: Medical records of 93 patients who underwent transoral robotic surgery (TORS) with concurrent neck dissection for oropharyngeal squamous cell carcinoma (SCC) between 2008 and 2013 were reviewed. Results: At the time of presentation, 60 (64.5%) patients had tonsil cancer, 14 (15%) had base of tongue, and 19 (21%) had carcinoma of unknown primary. High risk types of HPV and p16 positivity were 74.4% and 85.4%, respectively. Mean primary tumor size was 2.3 cm (range, 0.3-5.1 cm). Nodal status based on pathologic examination were N0 in 7 (7.5%) patients, N1 in 12 (12.9%), N2a in 25 (26.9%), N2b in 37 (39.8), N2c in 5 (5.4%), and N3 in 7 (7.5%). Average positive LN number was 2.56 (range, 0-37). Extracapsular spread (ECS) was identified in 29.1% of all patients. Primary tumor size had no effect on positive LN size, number or ECS. HPV positivity (rs = 0.25, P = .021), p16 overexpression (rs = 0.36, P = .001), and lymphovascular invasion (rs = 0.34, P = .001) were significantly associated with increased positive LN number. Positive LN number correlates with ECS (rs = 0.28, P =.009). Conclusions: HPV positivity, p16 overexpression, and lymphovascular invasion increase the risk of cervical lymph node metastasis. Increased primary tumor size does not necessarily mean advanced neck disease.