Prognostic value of lymph node ratio versus American Joint Committee on Cancer N classification for surgically resected human papillomavirus‐associated oropharyngeal squamous cell carcinoma

Abstract

Background We compared prognostic values of lymph node ratio (LNR) and AJCC 8 N classification in surgically resected human papillomavirus (HPV)‐associated oropharyngeal squamous cell carcinoma (OPSCC). Methods Using the National Cancer Database, we identified patients with HPV‐associated OPSCC from 2010 to 2016 who underwent definitive surgical resection. Patients were analyzed by nodal grouping (LNR, N stage) and adjuvant radiation therapy(RT). Primary endpoint was overall survival. Results We identified 4166 patients. Survival analysis showed significant improvement for LNR≤6% versus >6% (5 year OS% 92.7% vs. 83.7%, p < 0.001). N classification demonstrated good prognostic ability (5 year OS% for pN0, pN1, pN2 were 91.3%, 90.1%, 78.8%, p < 0.001), but poor separation among stages (compared to pN0: pN1 HR 1.40 [95% CI 0.63, 3.09], p = 0.41; pN2 HR 2.50 [95% CI 1.08, 5.81], p = 0.033). RT improved survival in the LNR > 6% group (5 year OS% 85.4% vs. 74.9%, p < 0.001; HR 0.41 [95% CI 0.28, 0.58], p < 0.001). Conclusions LNR should be considered an adjunct category in future staging systems for HPV‐associated OPSCC.