THE PREVALENCE OF HPV POSITIVE OROPHARYNGEAL SQUAMOUS CELL CARCINOMA AT A MAJOR REFERRAL CENTER IN SOUTHERN AFRICA

Abstract

<h3>Objective</h3> Limited data on the prevalence of human papilloma virus (HPV)–positive oropharyngeal squamous cell carcinoma (OPSCC) in Southern Africa exist. The aim of the current study was to determine the prevalence of HPV-positive OPSCC at a major referral public hospital (Tygerberg Hospital) in the Western Cape region, South Africa. <h3>Methods</h3> Sequential surgical samples of 266 cases of OPSCC diagnosed over a 10-year period (2007-2017) were selected for evaluation and relevant patient characteristics were documented. p16 immunohistochemistry was performed as a screening test. All p16-positive cases were further evaluated for HR-HPV using a novel DNA polymerase chain reaction technology (BD Onclarity HPV assay). <h3>Results</h3> Of 266 cases, 14% were positive for p16 (n = 36). Of 36 p16-positive cases, 23 were negative and 13 were positive for HR-HPV (5%) when evaluated by PCR. p16 was found to have a positive predictive value of 36.1%. HPV subtypes were HPV-16 (n = 10), HPV-18 (n = 1), HPV-52 (n = 1), and HPV-31 (n = 1). One case was positive for HPV-16 and HPV-31. HPV-positive OPSCC occurred in 10 men and 3 women with a mean age of 51 years (range, 33-72 years). Most HPV-positive OPSCC were nonkeratinizing (n = 10) or partially keratinizing (n = 1). In contrast, HPV-negative OPSCC were predominantly keratinizing (n = 218). <h3>Conclusions</h3> The presence of HR-HPV in 5% of cases suggests that HR-HPV as a minor etiologic agent in OPSCC at this institution. Because of its suboptimal positive predictive value (36.1%), p16 immunohistochemistry alone is insufficient to confirm an HPV-positive OPSCC at this center and, when positive, HPV-specific testing must be performed by one of the available platforms.