Histopathologic findings of HPV and p16 positive HNSCC.

OBJECTIVE

Human papilloma virus (HPV) and p16INKa (p16) positivity in head and neck squamous cell carcinomas (HNSCCs) is currently thought to be an encouraging prognostic indicator. However, the histopathologic changes responsible for this behavior are poorly understood. It is our objective to elucidate these histopathologic characteristics to help define the clinical utility of these markers.

DESIGN

Retrospective cohort study.

METHODS

71 HNSCC tumors between July 1, 2008 and August 30, 2009 were examined for HPV, p16, and epidermal growth factor receptor (EGFR). Specified pathologic features were examined: perivascular invasion (PVI), perineural invasion (PNI), grade of squamous differentiation, basaloid classification.

RESULTS

HPV and p16 had no direct impact on perineural or perivascular invasion. However, HPV and p16 were strongly predictive of poorly differentiated tumors, as well as basaloid squamous cell carcinoma (SCCA) (P < .001). Additionally, upon multivariate analysis, HPV(+) and p16(+) tumors had an increased risk of nodal metastasis (HPV: odds ratio [OR] = 23.9 (2.2, 265.1) p = .01; p16: OR = 6.5 (1.4, 31.2) p = .02; PVI: OR = 6.0 (1.6, 22.8) p < .01). The area under the curve (AUC) of receiver operating characteristic (ROC) curves demonstrated improved predictive value for lymph node metastasis above standard H&E histopathologic features (76.7%) for both HPV (83.2%) and p16 (81.3%) individually.

CONCLUSIONS

HPV(+) and p16(+) are highly predictive for poorly differentiated tumors and basaloid SCCA. Additionally, HPV and p16 positivity demonstrate superior predictive value for lymph node metastasis above standard H&E histopathologic features. Although exact recommendations should be tempered by considerations of primary tumor subsite, T-stage, and depth of invasion, head and neck multidisciplinary teams should strongly consider aggressive lymph node treatment for any HPV(+) or p16(+) tumor.