A systematic review of the HPV-attributable fraction of oropharyngeal squamous cell carcinomas in Germany

The prevalence of oropharyngeal squamous cell carcinoma (OPSCC) is increasing globally while the prevalence of other head and neck cancers is decreasing. The most likely reasons for this are a decreasing influence of smoking and the growing relevance of infections with the human papilloma virus (HPV) as a risk factor. A rise in the HPV-attributable fraction (HPV-AF) of OPSCC has been observed in many countries, yet a comprehensive review of prevalence rates and trends in Germany is lacking. To determine the current HPV-AF of OPSCC in Germany and to assess whether it has changed during the last decades, we performed a systematic literature review. We screened Medline and EMBASE for studies that reported the tumor HPV status of newly diagnosed OPSCC patients treated at medical centers in Germany by testing for both HPV DNA and p16(INK4a) overexpression to confirm involvement of HPV in tumorigenesis. Out of 287 screened studies, 14 studies with data from a total of 1819 OPSCC patients treated between 1988 and 2015 were included in the data synthesis. The reported average HPV-AF varied considerably between the studies, ranging from 11.5% (1988-2008) to 55.0% (2004-2009). Two of the included studies did not only provide the HPV-AF for the entire observed calendar period but also for separate years, allowing to more accurately assess changes over time. These studies reported increases in the HPV-AF from 21% in 2000 to 53% in 2015 and from 38% in 2004 to 71% in 2013, respectively.