Oropharyngeal Squamous Cell Carcinoma Outcomes by p16INK4a Antigen Status in a Veteran Population.

BACKGROUND

The correlation between head and neck squamous cell carcinoma (SCC) and human papillomavirus (HPV) has been of great interest. We aimed to study immunoexpression of the p16INK4a (p16) antigen, a surrogate marker for high-risk HPV infection, in oropharyngeal SCC among veterans to estimate HPV-related cancer and survival. Secondary aims included stratification of race and ethnicity, degree of tobacco and alcohol use, tumor location, stage, and age at diagnosis.

METHODS

A retrospective electronic health record review was performed between January 1, 2000, and December 31, 2008, at a tertiary-level US Department of Veterans Affairs (VA) medical center for veterans who were treated for oropharyngeal SCC, had follow-up for a minimum of 2 years, and for whom paraffin-embedded tissue was available. Paraffin-embedded tissue was analyzed for p16 expression.

RESULTS

We identified 66 veterans who met the inclusion criteria. p16 expression was observed in 29% of the patients. All patients were male with no difference in age at diagnosis between the groups. Among patients with p16-negative status, 60% were African American, whereas among patients with p16-postive status, 32% were African American (P = .04). Among patients with p16-postive status, 22% were tobacco-naïve, and 18% were alcohol-naïve vs 0% and 4%, respectively, of patients with p16-negative status (P = .005 and P = .12, respectively). Two-year survival was the same for both groups (P = .52).

CONCLUSIONS

We observed p16 expression in 29% of VA patients with oropharnygeal SCC, which was less than observed in non-VA populations. At presentation, both groups demonstrated a predilection for tonsil location and late stage without significant difference in age or disease-specific survival. Disparities in racial distribution and tobacco use between patients with and without p16-positive status appear like that reported in non-VA populations; however, the frequently reported younger age at presentation, lower stage, and improved prognosis were not observed.