Double Positivity for HPV DNA/P16INK4a Does Not Influence Survival of Patients With Oral Squamous Cell Carcinoma.

BACKGROUND/AIM: We investigated the prevalence of human papillomavirus (HPV) in a prospective cohort of patients with squamous cell carcinoma of the oral cavity (OSCC) using both p16INK4a and HPV DNA, i.e., double positivity, as a definition criterion. Additionally, we examined the association of HPV with survival.

PATIENTS AND

METHODS

Samples from 280 OSCC patients were analyzed for HPV-positivity using p16INK4a immunohistochemistry (IHC) and in situ hybridization (ISH)/LCD arrays, for HPV low and high-risk types. Only patients positive for both p16INK4a and HPV DNA were considered as HPV-positive. Survival probabilities and 95% confidence intervals were estimated using the Kaplan-Meier method. Cox proportional hazards models were used to assess HPV association with disease-free survival (DFS), cause-specific survival (CSS) and overall survival (OS) in a competing risks scenario.

RESULTS

Specimen from 30 (10.7%) patients were p16+ and HPV DNA+, while 31 (11.0%) were either p16+ or HPV DNA+ only. OS probabilities at five years for HPV-positive and -negative groups were 50.9% (35.4%-73.1%) and 52.9% (47.0%-59.5%), respectively. HPV double positivity influenced neither OS, CSS nor DFS: HR=0.84 (0.43-1.63), 1.64 (0.76-3.54) and 1.13 (0.55-2.35), respectively.

CONCLUSION

In contrast to oropharyngeal cancer, the prevalence of HPV in OSCC is low and the presence of HPV does not influence survival outcomes. Hence, there is no evidence to support a parallel transfer of therapy regimen for HPV-positive OPC to OSCC, in terms of therapy de-escalation and/or vaccination.