The epidemiology of head and neck squamous cell carcinoma in The Netherlands during the era of HPV-related oropharyngeal squamous cell carcinoma: Is there really evidence for a change?

Background
Several recent studies have shown that incidence of oropharyngeal carcinomas is rising in the Western World. This increase has been attributed to changes in the etiology of oropharyngeal carcinomas with a growing role for infections with Human Papilloma viruses. This nationwide study evaluates and compares trends in incidence, clinical behavior and tumor characteristics of oropharyngeal and oral squamous cell cancer.

Methods
This study comprised all 16,480 patients with primary squamous cell carcinoma of the oral tongue (OTSCC), oral cavity excluding oral tongue (OCSCC), and oropharynx (OPSCC) diagnosed from 1989 through 2008 in The Netherlands. We assessed trends in age-standardized incidence, second cancer risk and subsite specific relative survival (RS) over time.

Results
Incidence of OTSCC and OPSCC in males and incidence of all subsites in females increased significantly from 1989 through 2008. In males increases in incidence were largely restricted to the 50-64 year age group (estimated annual percentage change 2.2% and 3.2% for OTSCC and OPSCC, respectively), while in females incidence increased for most age groups. The incidence of OCSCC (excl. oral tongue) and OPSCC before 50 years of age decreased. Patients with OPSCC showed the poorest prognosis with a relative survival of 41.6% after 5 years and 29.4% after 10 years (P < 0.001) over the entire period 1989-2008. However survival increased substantially for OPSCC patients over time (5-year RS of 37.2% in 1989-1993 to 47.6% in 2004-2008, P < 0.001).

Conclusion
Although incidence of OPSCC did increase since 1989, especially in females, similar increases were seen for OCSCC (excl. oral tongue) and OTSCC. Our study does not appear to support that HPV is the main contributor to a rising incidence of OPSCC as the effects of changes in smoking and alcohol use cannot be discounted.

Keywords
Head and neck cancer; Oropharynx; Oral cavity; Epidemiology; The Netherlands; HPV; Tobacco; Alcohol; Incidence