Impact of Nodal Metastases in HPV-Negative Oropharyngeal Cancer.

Background: The updated American Joint Committee on Cancer (AJCC) 8th Edition staging manual restructured nodal classification and staging by placing less prognostic emphasis on nodal metastases for human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPSCC). However, there was no change for HPV-negative OPSCC. The purpose of our study is to examine the impact of nodal metastases on survival in HPV-negative OPSCC.

Methods: HPV-negative OPSCC was queried from the National Cancer Database (NCDB) and Surveillance, Epidemiology and End Results program (SEER) databases. Univariable and multivariable models were utilized to determine the impact of nodal status on overall survival. These patients were reclassified according to AJCC 8 HPV-positive criteria (TNM8+) and risk stratification was quantified with C-statistic.

Results: There were 11,147 cases of HPV-negative OPSCC in the NCDB and 3,613 cases in SEER that were included in the nodal classification analysis. Unlike nonoropharyngeal malignancies, increased nodal stage is not clearly associated with survival for patients with OPSCC independent of HPV status. When the TNM8+ was applied to HPV-negative patients, there was improved concordance in the NCDB cohort, 0.561 (plus minus) 0.004 to 0.624 (plus minus) 0.004 (difference +0.063) and the SEER cohort, 0.561 (plus minus) 0.008 to 0.625 (plus minus) 0.008 (difference +0.065).

Conclusions: We demonstrated a reduced impact of nodal metastasis on OPSCC survival, independent of HPV status and specific to OPSCC.

Impact: We demonstrate, for the first time that when nodal staging is deemphasized as a part of overall staging, we see improved concordance and risk stratification for HPV-negative OPSCC. The exact mechanism of this differential impact remains unknown but offers a novel area of study.