Title : Need of monitoring human papillomavirus infection among oral and oropharyngeal squamous cell carcinoma patients from setting with high incidence of cervical cancer
Abstract:
Background: There has been a global upsurge of oropharyngeal cancer (OPC) cases associated with increased human papillomavirus (HPV) infection. In Tanzania and Sub-Saharan African countries data on the same is lacking and HPV among OPC patients is not investigated routinely. The recommended practice, however not practiced in most LMICs, is to determine HPV infection status to oral and oropharyngeal squamous cell carcinoma (OPSCC) before treatment since the positive cases are treated with de-escalated regime because they respond better to treatment.
While the burden of HPV in cervical cancer is well established the role of HPV is not well documented in countries where cervical cancer is endemic. Without baseline data it may be difficult to later quantify the effect of HPV vaccination in reduction of OPC. It is better to start now establishing means of monitoring the prevalence of HPV in both OPC patients and where possible the health individuals in settings where HPV related cervical cancer is more prevalent.
Aim: This study aimed at determining the occurrence of HPV status to OPSCC through p16 immunohistochemistry (IHC) and in situ hybridization (ISH).
Materials and Methods: The study was done at Muhimbili National Hospital (MNH) and MUHAS Dental Clinic from August 2020 and Dec 2022. The biopsies were taken from the cases clinically suspected to have OPSCC. Following confirmation of OPSCC histologically, the blocks of 218 patients were obtained and screened for possibility of obtaining quality tissue materials for tumour microarray (TMAs) for IHC and ISH whereby blocks for 172 patients qualified. Tissues were transferred to Haukeland University Hospital (Norway) where TMAs were prepared, and then IHC and ISH were done. In addition, IHC for p53 was performed to search for association of occurrence of these biomarkers.
Results: Out of 172 cases of OPSCC the p16 overexpression was found in 15 cases (8.72%) which had over 70% of cells in the specimen stained. In-situ hybridization was done in all cases and only 2 (1.16%) were positive. The majority of p16 positive cases showed only weak stains on ISH. The majority of the 15 cases which showed p16 overexpression were located on the tongue followed by mandibular gingiva and buccal. Two thirds were males and 40% were aged below 60 years with almost all at clinical stage IV.
Conclusion: Findings concur with research done elsewhere in sub-Saharan Africa showing that HPV infection among OPSCC is low. Among these few cases males dominated. Given the current situation of genital HPV infections, there is a need for constant surveillance of the same for oral and pharyngeal area.
Recommendation: There is a necessity to routinely determine HPV status using p16 IHC and RNA ISH among OPSCC cases in Tanzania before initiation of treatment for the sake of estimating prognosis and for constant surveillance of HPV burden.
