Characteristics and Impact of p16 Expression in Patients With Oropharyngeal Squamous Cell Carcinoma in Tanzania.

Abstract

Oropharyngeal cancer is on the rise, despite declines in other head and neck cancers. The primary cause of this increase is human papillomavirus (HPV) infection, which accounts for over a quarter of new cancer patients in Tanzania. These cancers are largely preventable through HPV vaccination. HPV-associated oropharyngeal squamous cell carcinoma (OPSCC) is recognized as a distinct molecular and clinical entity, with unique demographics, staging, survival, and prognosis. International guidelines recommend that all staging, prognosis, and treatment decisions for OPSCC occur after determining the p16 expression, a surrogate immunohistochemical marker for HPV infection. However, current Tanzanian guidelines and clinical practice do not incorporate p16 immunohistochemistry (IHC) testing, despite the availability of qualified pathologists and laboratories. This retrospective hospital-based cohort study was conducted at the Ocean Road Cancer Institute (ORCI) and Muhimbili National Hospital in Dar es Salaam, Tanzania. A total of 83 patients with OPSCC were included. We assessed the sociodemographic and clinicopathologic profiles and the impact of p16 expression on overall survival (OS) in patients with OPSCC treated at the ORCI. The prevalence of p16-positive OPSCC was found to be 43.4%. Patients with p16-positive tumors were younger and predominantly male and had a 3-year OS of 36% compared with 16.6% in those with p16-negative tumors. Our findings support the use of p16 IHC as a prognostic biomarker for OPSCC. In addition, the high prevalence of p16-positive OPSCC in our cohort suggests the broader implementation of gender-neutral HPV vaccination across Tanzania.