Importance: The most common cause of oropharyngeal squamous cell carcinoma is human papillomavirus (HPV) infection, and currently the standard of care to determine the HPV infection status in this type of carcinoma is to use p16 immunohistochemistry as a surrogate marker of high-risk HPV infection. Although p16 immunohistochemistry is limited by the inability to determine the specific HPV genotypes, oral gargle samples may be a readily available source of HPV DNA for genotyping.
Objective: To determine the specific HPV genotypes present in both oral gargle samples and tumor specimens.
Design, setting, and participants: This prospective, biomarker cohort study conducted at a single specialized cancer hospital in Florida screened approximately 800 potentially eligible participants from May 2014 through October 2017. To be eligible for participation, patients had to meet all of the following criteria: 18 years of age or older, male sex, newly diagnosed as having stage I to IV cancer of the oropharynx, a squamous cell carcinoma diagnosis, treatment naive or at least 4 weeks after chemoradiation or surgical treatment of other diseases, fully understand the study procedures and risks involved, and voluntarily agree to participate by signing an informed consent statement.
Main outcomes and measures: Detection rate of HPV infection and HPV genotypes in oral gargle samples and tumor specimens.
Results: A cohort of 204 male participants with newly diagnosed oropharyngeal squamous cell carcinoma was assessed in this prospective collection of comprehensive clinical data and oral gargle samples. Most study participants (190 [93.1%]) were white and ever smokers (114, 55.9%), with a median age of 61 years (range, 35-87 years). The HPV infection status could be assessed in 203 of 204 participants (99.5%) using oral gargle samples: 35 samples (17.2%) were negative for HPV infection, whereas 168 samples (82.8%) were positive for HPV infection. The detection rate of HPV genotypes was 93.0% in tumor specimens (160 specimens) and 82.8% (168 samples) in oral gargle samples. The oral gargle samples frequently had low-risk HPV genotypes that were not detected in tumors, but these low-risk genotypes were always a coinfection with high-risk genotypes.
Conclusions and relevance: Oral gargle samples can be used to detect the majority of clinically relevant HPV genotypes found in oropharyngeal squamous cell carcinoma, but the interpretation of HPV detected in these samples should be assessed with caution for general cancer risk assessment given that sensitive assays can concomitantly detect low-risk genotypes.