Epidemiological Study of p16 Incidence in Head and Neck Squamous Cell Carcinoma 2005-2015 in a Representative Northern European Population

Simple Summary Human papillomavirus (HPV) infection is a known risk factor for developing head and neck squamous cell carcinoma (HNSCC), especially in the oropharyngeal region. Determining HPV status is important, as both survival and treatment response are dependent on HPV expression. p16 immunohistochemistry is a widely used method to detect HPV positivity in cancer. The aim of this study was to determine the prevalence and associations of p16 positivity with survival in all patients diagnosed with new HNSCC in Southwest Finland between 2005 and 2015. p16 positivity involved a high locoregional correlation, as 72% of all p16-positive tumors were located in the oropharynx. p16 positivity in the oropharynx was associated with an increased likelihood of lymph node metastasis, a smaller primary tumor size and a sparse history of smoking and alcohol consumption. Notably, in all studied categories, HNSCC patients benefited from combining chemotherapy with radiotherapy, regardless of p16 expression. The incidence of human papillomavirus (HPV)-associated head and neck squamous cell carcinomas (HNSCC) has increased globally. Our research goal was to study HNSCC incidence in a representative Northern European population and evaluate the utility of the HPV surrogate marker p16 in clinical decision-making. All new HNSCC patients diagnosed and treated in Southwest Finland from 2005-2015 (n = 1033) were identified and analyzed. During the follow-up period, the incidence of oropharyngeal (OPSCC) and oral cavity squamous cell carcinoma (OSCC) increased, while the incidence of laryngeal squamous cell carcinoma (LSCC) decreased. This clinical cohort was used to generate a population-validated tissue microarray (PV-TMA) archive for p16 analyses. The incidence of p16 positivity in HNSCC and OPSCC increased in southwest Finland between 2005 and 2015. p16 positivity was mainly found in the oropharynx and was a significant factor for improved survival. p16-positive OPSCC patients had a better prognosis, regardless of treatment modality. All HNSCC patients benefited from a combination of chemotherapy and radiotherapy, regardless of p16 expression. Our study reaffirms that p16 expression offers a prognostic biomarker in OPSCC and could potentially be used in cancer treatment stratification. Focusing on p16 testing for only OPSCC might be the most cost-effective approach in clinical practice.