Impact of Lymph Node Yield on Survival in Surgically Treated Oropharyngeal Squamous Cell Carcinoma.

Objectives: (1) To estimate the association between neck dissection lymph node yield (LNY) and survival among patients with surgically treated human papilloma virus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC). (2) To identify a clinically relevant quality metric for surgical treatment of HPV-related OPSCC.

Study Design: Retrospective cohort study.

Setting: National Cancer Database.

Subjects And Methods: From the National Cancer Database, 4130 patients were identified with HPV-associated OPSCC treated with primary surgery from 2010 to 2016. Based on prior literature, an adequate neck dissection LNY was defined as ≥18 lymph nodes. To determine whether LNY is associated with survival, univariable and multivariable Cox proportional hazards regression was performed. Analysis was stratified by adjuvant therapy regimen.

Results: A total of 2113 patients (51.2%) underwent surgery with or without adjuvant radiation (S ± RT), and 2017 patients (48.8%) underwent surgery with adjuvant chemoradiation. LNY ≥18 was associated with a 5-year survival benefit of 7.15% (91.7% for LNY ≥18, 84.5% for LNY <18, = .004) for the S ± RT cohort on unadjusted survival analysis. For the S ± RT group, LNY ≥18 was associated with decreased hazard of death (hazard ratio, 0.45; 95% CI, 0.29-0.70; < .001) after adjustment for patient characteristics, TNM staging, surgical margins, extranodal extension, and treating facility characteristics. For surgery with adjuvant chemoradiation, the adjusted hazard ratio estimate for LNY ≥18 was 0.64 (95% CI, 0.41-1.00), but the result was not statistically significant ( = .052).

Conclusion: An adequate LNY from a neck dissection may affect survival when HPV-related OPSCC is treated with up-front surgery.