A descriptive study of human papilloma virus in upper aero-digestive squamous cell carcinoma at Uganda cancer institute assessed by P16 immunohistochemistry.

Background: Cancer burden in sub-Saharan Africa is on the rise with one-third of cancers estimated to be caused by infectious agents. Head and neck squamous cell cancer (HNSCC) is the sixth most common malignancy in sub-Saharan Africa and includes tumors in the Upper Aero-digestive Tract (UADT). The established risk factors are tobacco and alcohol exposure with a recent recognition of the role of Human Papilloma Virus (HPV). The HPV related HNC is seen predominantly in the oropharynx, presents at a younger age and has a better prognosis. With a rapidly increasing incidence of these cancers in the developed world, it was important to study HPV in HNC in Uganda. The HPV can be detected using P16 immunohistochemistry as a surrogate marker thus making it suitable for screening. The study aimed at establishing the presence of HPV and the commonly affected sites in UADT squamous cell carcinoma (SCC) at Uganda Cancer Institute (UCI) using P16 immunohistochemistry.

Methodology: This was a cross sectional study in which 59 patients with histologically proven SCC from the oral cavity, oropharynx, larynx and hypopharynx were recruited. These patients' demographics and clinical data were collected. Tissue sections from retrieved histology samples were stained by Haematoxylin and Eosin to reconfirm SCC. Subsequently, P16 expression was determined using P16 immunohistochemistry.

Results: Seventy-one patients were enrolled and 59 patients with confirmed SCC of the sites of interest were analyzed. The majority (79.7%) of the participants were male and over 50 years. 59.3% were tobacco smokers, 66.1% used alcohol, 52.2% used both. Only 27.1% used none of the substances. Only 27.1% of the participants were HIV positive. Most of the tumors were in the larynx (37.3%) and 64.4% were overall TNM stage 4. The overall prevalence of HPV in UADT SCC at UCI was 20.3, 95%CI 10.9-32.8. The oropharynx had the highest prevalence (30.8%).

Conclusion: The prevalence of HPV in UADT SCC at UCI is significant at 20.3%. The most affected site, is the oropharynx. Vigilant HPV screening of these sites with confirmation where possible is recommended.