Human papillomavirus-related small cell carcinoma of the oropharynx

HPV specific testing: a requirement for oropharyngeal squamous cell carcinoma patients

Human papillomavirus (HPV) testing is now recommended as part of the work up for patients with oropharyngeal squamous cell carcinoma (OPSCC) and those patients with cervical lymph node metastasis of unknown origin. The laboratory testing strategy should accurately assess the presence or absence of oncogenic HPV infection in routinely collected tumour samples that are subject to standard fixation protocols, alcohol-fixed cytological preparations and formalin-fixed tissue samples. The HPV status should correlate with biologically relevant outcome measures such as overall, disease-specific and disease-free survival. Whilst increased expression of p16 by immunohistochemistry is considered to be a surrogate marker of oncogenic HPV infection and is a validated independent prognostic biomarker, only HPV specific tests provide definitive evidence of the aetiological agent. We provide an overview of HPV testing in OPSCC, justifying the use of HPV specific tests. We examine the analytical accuracy of HPV specific tests against the 'reference' test--high risk HPV mRNA in fresh tissue--and contrast this with the performance of p16 immunohistochemistry as a stand alone test. We highlight the added value of HPV specific tests in prognostication, clinical trial design, and population-based disease surveillance. We consider that HPV specific testing is the starting point for developing increasingly informative biomarker panels in the context of 'stratified medicine'. We briefly frame test information in the context of disclosure of HPV status to patients. We conclude that only a testing strategy that includes HPV specific tests can deliver more effective care for patients with OPSCC. The international head and neck oncology community should work together to clearly define the minimum requirements for assigning a diagnosis of HPV-related OPSCC in order to ensure consistent reporting of this emerging and increasingly prevalent disease.

HPV-related squamous cell carcinoma variants in the head and neck

The great majority of HPV-related carcinoma of the oropharynx is nonkeratinizing squamous cell carcinoma. More recently, an increasing number of squamous cell carcinoma variants that are HPV positive are being reported in the oropharynx, as well as in other head and neck sites. As a result, several clinical and pathologic questions have emerged. Importantly, questions raised include whether the virus is biologically active and involved in the pathogenesis of these tumors, and whether there are clinical implications with regard to patient outcome and treatment modality changes that may be needed in HPV-related variants. Examples of HPV-related squamous cell carcinoma variants that will be addressed here include: basaloid squamous cell carcinoma, undifferentiated carcinoma, adenosquamous carcinoma, papillary squamous carcinoma, and small cell carcinoma. Some investigations have suggested a favorable prognosis in some variants, analogous to that of the conventional nonkeratinizing (basaloid) carcinoma, while others showed poorer outcome. So far, the number of studies on this subject is limited and the number of cases evaluated in each investigation is few. Because of this, it is prudent at this stage not to alter management protocols as a result of identification of HPV in these variants and to await additional studies.