Extranodal Extension Improves AJCC-8 Accuracy in HPV+ Oropharyngeal Cancer in a High-Risk Population

The American Joint Committee on Cancer's 8th edition (AJCC-8) separates oropharyngeal squamous cell carcinomas (OPSCCs) into human papillomavirus-positive (HPV+) tumors and HPV-negative tumors. Although AJCC-8 improves prognostic prediction for survival for the majority of HPV+ OPSCC, outliers are still encountered. The goal of this manuscript is to validate the AJCC-8 as a better metric of survivability than the AJCC-7 in an historically under-served rural population with confounding variables, such as tobacco use, alcohol consumption, and poor health care access and to analyze the role of extranodal extension (ENE) in this population.

Retrospective cohort study.

Compared to AJCC-7, AJCC-8 had a higher odds ratio (OR) for predicting mortality of stage IV HPV+ OPSCCs versus stages I-III. On multivariate analysis, HPV+ OPSCCs with ENE had a higher OR of mortality compared to ENE- OPSCCs. In addition, HPV+ OPSCC patients with a Charlson Comorbidity Index (CCI) > 3 had a higher OR of mortality compared to those with a CCI ≤ 3. Patients with Medicaid/self-pay status had a higher OR of mortality compared to those with private insurance/Medicare. Finally, patients from rural populations had a higher OR of presenting with stage IV disease, a CCI > 3, and Medicaid/self-pay status.

Despite not being a discrete part of the AJCC-8 staging rubric, ENE was found to have a significant impact on mortality among this population, whereas tobacco use had no effect. Rural patients were more likely to present with stage IV disease, CCI > 3, and Medicaid/self-pay status. Stage IV disease was also associated with a higher OR of mortality.

4 Laryngoscope, 133:2621-2626, 2023.