ABSTRACT
CONTEXT.: Limited data exist on the prevalence of human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma in sub-Saharan Africa. OBJECTIVE.: To determine the prevalence of HPV-positive oropharyngeal squamous cell carcinoma at a large tertiary care center in South Africa. DESIGN.: A total of 266 oropharyngeal squamous cell carcinomas diagnosed during an 11-year period (2007-2017) were selected for evaluation. Cases staining positive for p16 immunohistochemistry were evaluated for high-risk HPV using the BD Onclarity assay (BD Diagnostics, Sparks, Maryland). RESULTS.: Of 266 oropharyngeal squamous cell carcinomas, 14% (n = 36) were positive for p16. Polymerase chain reaction for high-risk HPV performed on the p16-positive cases was negative in 23 cases and positive in 13 cases (13 of 266; 5%). p16 showed a positive predictive value of 36.1%. The HPV subtypes were HPV-16 (n = 10), HPV-18 (n = 1), HPV-52 (n = 1), and HPV-31 (n = 1). Human papillomavirus-positive cases occurred in 10 men and 3 women (mean age, 51 years) and arose from the tonsil (n = 10) or base of the tongue (n = 3). The HPV-positive cases were non-keratinizing (n = 10) or partially keratinizing (n = 1). Partially/nonkeratinizing cases revealed a modest improvement in p16 positive predictive value (11 of 21; 52.4%). CONCLUSIONS.: The presence of high-risk HPV in 5% of cases suggests that high-risk HPV is a minor etiologic agent in oropharyngeal squamous cell carcinoma in this region. Given its suboptimal positive predictive value, p16 is not a reliable marker for high-risk HPV infection in this region. When p16 is positive, HPV-specific testing is necessary. The identification of less common high-risk HPV types, HPV-52 and HPV-31, may influence current local vaccination strategies.
Subject(s)
Carcinoma, Squamous Cell , Head and Neck Neoplasms , Oropharyngeal Neoplasms , Papillomavirus Infections , Carcinoma, Squamous Cell/pathology , Cyclin-Dependent Kinase Inhibitor p16/metabolism , Female , Human papillomavirus 16/genetics , Human papillomavirus 16/metabolism , Humans , Male , Middle Aged , Oropharyngeal Neoplasms/pathology , Papillomaviridae/genetics , Papillomaviridae/metabolism , Papillomavirus Infections/complications , Papillomavirus Infections/diagnosis , Papillomavirus Infections/epidemiology , Prevalence , South Africa/epidemiology , Squamous Cell Carcinoma of Head and Neck/epidemiology , Tertiary Care CentersABSTRACT
BACKGROUND: Sentinel lymph node biopsy (SLNB) is a technique that is widely used in the management of early breast cancer. Surgeons are encouraged to validate their initial SLNB results by performing an audit in which both a SLNB and an axillary lymph node dissection (ALND) are performed. For surgeons in solo private practice this is not financially viable as the SLNB would not be paid for by the medical insurance companies. METHODS: Forty consenting patients were enrolled in the audit. The initial 5 patients (group A) were entered into a traditional audit - an ALND and a SLNB. The next 35 patients (group B) formed part of a modified audit - an axillary sample was performed if the sentinel node was negative (group B1) and an ALND if the node was positive (group B2). RESULTS: Ninety-two per cent of patients with an ipsilateral sentinel axillary node on preoperative scintigraphy had their node identified at the time of surgery. Eight patients had evidence of lymphatic spread. Two patients had parasternal sentinel nodes which were not removed. Group A had a mean of 10.8 nodes removed, group B1 5.8 nodes, and group B2 13.2 nodes. Twenty-three of 35 patients (66%) in group B were spared an axillary dissection. CONCLUSION: The modified audit of group B allowed patients to benefit from the procedure (and thus the medical aids charged) and yet permitted our team to ascertain the accuracy of the technique in our hands. We feel this is an approach that may be used by other surgeons working alone.
