Oropharyngeal Squamous Cell Carcinoma and Human Papillomavirus in African American Populations Open Access

Rereddy, Shruthi Kirthi (2015)

Permanent URL: https://etd.library.emory.edu/concern/etds/vh53wv862?locale=en


Purpose: Oropharyngeal squamous cell carcinoma (OPSCC) mortality in the U.S. is higher among African American patients compared to Caucasians. Tumors positive for human papillomavirus (HPV) are associated with decreased OPSCC mortality risk. Variation in tumor HPV status may explain the OPSCC mortality difference by race. This study examines overall survival in African American and Caucasian patients with HPV-positive and HPV-negative OPSCC.

Study Design: A retrospective cohort of 223 patients with biopsy-proven squamous cell carcinoma of the oropharynx was identified from tumor board registries and surgical logs. Patient demographics, risk factors, tumor characteristics, treatment modality, and comorbid disease were abstracted from medical records. Tumor HPV status was determined by p16 immunohistochemistry (IHC). Prevalence of p16-positive disease was compared between races using Chi square tests. Associations between p16-positive disease and race were analyzed using univariate and multivariate logistic regression models. Survival was analyzed using Kaplan-Meier plots and Cox proportional hazards models.

Results: The prevalence of p16-positive disease varied by race with 77.7% of Caucasian patients testing positive compared to 56.3% of African American patients (p=0.003). African American patients had significantly poorer survival compared to Caucasian patients both overall and when stratified by p16-negative and p16-positive groups (p<0.0001, p=0.0253, p=0.0024, respectively). African American patients had decreased survival compared to Caucasian patients even after adjusting for p16 status, tumor stage, alcohol and tobacco use, and socioeconomic factors (HR=2.10, p=0.0244).

Conclusions: Caucasian OPSCC patients were more likely to have p16-positive tumors compared to African American patients, however this difference did not fully explain the mortality risk difference between the two races even after adjusting for socioeconomic and behavioral factors. This study contributes to the growing evidence that tumor HPV status varies by race and may contribute to racial disparities in outcomes for OPSCC.

Table of Contents

Introduction. 1

Background. 3

Methods. 7

Results. 12

Discussion. 16

References. 21

Tables and Figures. 24

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