High Risk Human Papillomavirus, Human Immunodeficiency Virus and Epstein Barr-virus in Head and Neck Squamous Cell Carcinoma Patients at Kenyatta National Hospital

Abstract

Background: Smoking and alcohol are the traditional well-known risk factors for head and neck cancer (HNC). In the recent past, human papillomavirus (HPV) has been recognized as risk factor for some head and neck squamous cell carcinomas (HNSCC) specifically Oropharyngeal Squamous Cell Carcinoma. The HPV is classified into 5 groups namely alpha, beta, gamma, mu and nu on the basis of the DNA sequence similarities. The alpha HPVs show tropism for cutaneous and mucosal epithelium and are further categorized into low and high-risk types depending on their ability to cause malignancy. The fifteen high risk human papillomavirus (HR-HPV) types associated with malignancy in the cervix, anogenital and head and neck areas are HPV 16, 18, 31, 33, 35, 39, 45, 51,52, 56, 58, 68, 69, 73 and 82. High risk HPV associated HNSCC is characterized by specific features not seen in HPV-negative HNC like male gender, younger age, higher socio-economic status and minimal or no alcohol and cigarette use among others. HPV status, when known, plays a role in the choice of treatment for HNSCC. This has not been adopted at Kenyatta National Hospital (KNH) for lack of supportive evidence of HPV presence in HNSCC at the institution. Objectives: The primary objectives of the study were to determine the prevalence and genotypes of HR-HPV among patients with HNSCC at KNH as well as their clinical and pathological characteristics and predictors. The secondary objectives of the study were to determine the prevalence of HR-HPV among Human Immunodeficiency Virus (HIV) positive HNSCC patients and the presence of HR-HPV and Epstein Barr Virus (EBV) co-infection in the nasopharyngeal carcinoma (NPC) patients among the HNSSC patients at KNH; as well as the characteristics of the respective patients. Study design: This was a descriptive cross-sectional study.

Study setting: The study was carried out at the Ear Nose and Throat – Head and Neck (ENT-HN) and Maxillofacial clinics and wards at KNH. The histology and HIV work up was carried out at the hospital’s pathology and immunology laboratories respectively while polymerase chain reaction (PCR) test was done at the KAVI-Institute of Clinical Research (KAVI-ICR) laboratory. Study Duration: The study was conducted between January 2015 and December 2018. Study population: This comprised of patients with HNSCC who presented to the ENT-HN and Maxillofacial Departments of KNH during the study period and consented to participate in the study. Materials and Methods: One hundred and sixty patients with HNSCC were enrolled. Their demographic details and medical history were taken. A complete ENT-HN examination was done. The appropriate haematological work-up, including HIV immunoassay, and radiological work-up for the tumours was done. Two tissue biopsies were taken from the primary tumour for histomorphological diagnosis and DNA extraction. The extracted DNA was subjected to HPV real time PCR for all patients and to EBV real time PCR for the sixty-two nasopharyngeal carcinoma patients. Data analysis: This was performed using SPSS version 21.0 statistical software. Summary statistics such as means, median and standard deviations were used to describe the distribution of the continuous variables. Descriptive analysis was performed on all variables and summarized into

frequency tables and charts. Pearson Chi square was applied to categorical data to test for association between independent and dependent variables. Fisher’s exact test was employed when cell numbers were small. A p-value less than 0.05 was considered significant. Results: One hundred and sixty patients with HNSCC aged 16 to 87 years with median age of 54.0 years were recruited into the study. There were 117(73.1%) males and 43(26.9%) females. Sixty-two (38.8%) of the patients had nasopharyngeal carcinoma. Most 136(85%) of the patients were drawn from Nairobi and its environs with majority140(87.5%) presenting with advanced disease (stage 3). Twelve (7.5%) of the 160 HNSCC patients tested positive for HR-HPV. Of these, ten were HPV 56, one was HPV 52 and one HPV 33. There was no HPV type 16 or 18. Out of the 160 patients with HNSCC, 10(6.3%) tested positive for HIV and only two (20%) of the ten HIV positive patients both of whom had NPC, tested positive for HPV 56. There were no differences in clinical or pathological characteristics between HR-HPV and non- HR-HPV associated HNSCC. All 62 nasopharyngeal carcinoma patients tested positive for EBV while seven (11.3%) tested positive for both EBV and HR-HPV. Conclusion: The prevalence of HR-HPV at KNH is low (7.5%) among HNSCC patients. Only three HR-HPV types 33, 52 and 56 were detected. There were no clinical or pathological predictors for HR-HPV associated HNSCC. In contrast there was high (20%) prevalence of HR-HPV among HIV positive HNSCC patients, and all the cases had HPV 56. There is 100% EBV and 11.3% HR-HPV presence in NPC patients at KNH with features consistent with high NPC incidence status. Recommendations: Considering the low prevalence and the absence of HPV types 16 and 18 in HNSCC patients at KNH, the role of HR-HPV in HNSCC in this population is insignificant and

does not warrant routine testing for HR-HPV in all HNSCC patients. The relatively higher prevalence of HR-HPV among HIV positive HNSCC patients may be useful in directing the focus of future studies to these specific populations. Finally, due to the high prevalence of EBV in NPC, it may be prudent to adopt EBV serology in screening and follow up of NPC patients