Chapter 1 - Epidemiology, Risk factors and Pathogenesis of Squamous Cell Tumours
HPV infection: It is the cause of a distinct subset of HNSCCs that occur primarily in the oropharynx. The proportion of HPV-positive (HPV+) OPCs is growing.
HPV Type 16 (HPV16) is responsible for more than 90% of HPV+ OPCs. The time from first oral HPV infection to the development of cancer is estimated to be more than a decade.
Measures of sexual behaviour (number of vaginal and oral partners, history of genital warts) have been associated with HPV+ OPC.
Patients with HPV+ OPC are less likely to be smokers than HPV-negative (HPV-) patients. However, approximately 50% of patients with HPV+ OPC have a history of tobacco use.
Individuals with HPV+ OPC tend to be male and white, although these characteristics do not predict HPV positivity. In addition, they present at a younger age at diagnosis.
HPV+ OPC is characterised by an earlier T stage at presentation but with extensive nodal involvement. However, prognosis is better compared with tobacco-related HNSCC.
Incidence patterns by ethnic origin have changed over time. Incidence of HNSCC in Black people has been declining since the 1990s and is currently lower than in White people.
Other risk factors for HNSCC include immunosuppression (organ transplant recipients, human immunodeficiency virus), systemic diseases (lichen) and genetic diseases (Fanconi anaemia).
Nasopharyngeal and paranasal sinus cancers are associated with the Epstein-Barr virus (EBV). Nasopharyngeal cancer is common in endemic areas (Southern China, Northern Africa).
Revision Questions
- Which type of HPV is associated with the majority of HPV+ OPCs?
- What are the clinical features of HPV+ OPC?
- Which virus is associated with nasopharyngeal cancer?
