Genotypes and prevalence of high-risk human papillomavirus among patients diagnosed with head and neck cancers at Alexandria Cancer Centre, Eldoret

Abstract

Background: American Joint Committee on Cancer defines Head and neck oncology as malignancies arising from epithelial lining of: oral cavity, nasal cavity, pharynx, larynx, paranasal sinuses and salivary glands. Global Cancer Statistics 2018 data, shows proportion of head and neck cancer to all cancers being 4.9% globally, while in Kenya it is 6%. Mortality rates globally are at 51%, while in Kenya it is at 73.4%. Research has shown the role of various high risk - Human papillomavirus (hr-HPV) genotypes in the rising incidence of head and neck cases globally. Several trials have shown that patients with Human papillomavirus positive head and neck cancer have better overall survival compared to the Human papillomavirus negative patients attributed to increased sensitivity to chemo-radiation therapy. Alexandria Cancer Centre and Palliative Care Hospital is one of the major cancer facilities in Western Kenya Region that is accredited by National Hospital Insurance Fund (NHIF) thus, making it accessible to people of all walks of life. Fortunately, samples are processed at Pathologist Lancet Laboratories which is a well-established institution with equipment and protocols in place for use in the present study. Objectives: The broad objective was to assess the genotypes and occurrence of highrisk Human papillomavirus among patients diagnosed with head and neck cancer at Alexandria Cancer Centre and Palliative Care Hospital, Eldoret between January 2017 and December 2018. Methods: This was a retrospective study with laboratory analysis between January 2017 and December 2018. Patient files were reviewed. Stored tissues were retrieved and: repeat microscopy, p16 Immunohistochemistry and Human papillomavirus Polymerase Chain Reaction were carried out. Data was analyzed by use of Microsoft Excel (2016). Results: Head and neck cancer accounted for 8.8% (89/1016) of all malignancies at Alexandria Cancer Centre and Palliative Care Hospital. There were more males (64%) than females (36%), with a mean age of 50.9 ± 17.6 years. Most patients came from Western Kenya Region. About one third (35.7%) were farmers and students combined. A total of 16 samples (16/29) (55.2%) tested p16 positive, of these 2 (12.5%) tested positive with HPV PCR. One of these was from an 87-year-old female diagnosed with tongue cancer. Molecular analysis revealed the genotype to be HPV 52. The other one was from a 49-year-old male with cancer of the post nasal space who had multiple co-infections with HPV: 35, 52 and 59 genotypes. It is important to note that these genotypes have been rarely isolated elsewhere. Conclusion: The prevalence of head and neck cancer at Alexandria Cancer Centre and Palliative Care Hospital is above both the global and national average pointing to a likely higher prevalence in this region. The potential role of the unique Human papillomavirus genotypes identified in this study require further investigations. Recommendations: Further prospective studies with a larger sample size in order to try and gain a better understanding of the prevalence of Human papillomavirus and high-risk genotypes associated with head and neck cancer in Kenya. Additional data will allow to close the gap of knowledge between Western countries and the sub- Saharan African region, especially in Kenya which has a high burden for head and neck cancer. This could play a big role in assisting health authorities in implementing public health strategies like vaccinations and will aid in allocating necessary resources.