Prognostic implications of p16 and HPV discordance in oropharyngeal cancer (HNCIG-EPIC-OPC): a multicentre, multinational, individual patient data analysis

Background: p16INK4a (p16) immunohistochemistry is the most widely used biomarker assay for inferring HPV causation in oropharyngeal cancer in clinical and trial settings. However, discordance exists between p16 and HPV DNA or RNA status in some patients with oropharyngeal cancer. We aimed to clearly quantify the extent of discordance, and its prognostic implications. Methods: In this multicentre, multinational individual patient data analysis, we did a literature search in PubMed and Cochrane database for systematic reviews and original studies published in English between Jan 1, 1970, and Sept 30, 2022. We included retrospective series and prospective cohorts of consecutively recruited patients previously analysed in individual studies with minimum cohort size of 100 patients with primary squamous cell carcinoma of the oropharynx. Patient inclusion criteria were diagnosis with a primary squamous cell carcinoma of oropharyngeal cancer; data on p16 immunohistochemistry and on HPV testing; information on age, sex, tobacco, and alcohol use; staging by TNM 7th edition; information on treatments received; and data on clinical outcomes and follow-up (date of last follow-up if alive, date of recurrence or metastasis, and date and cause of death). There were no limits on age or performance status. The primary outcomes were the proportion of patients of the overall cohort who showed the different p16 and HPV result combinations, as well as 5-year overall survival and 5-year disease-free survival. Patients with recurrent or metastatic disease or who were treated palliatively were excluded from overall survival and disease-free survival analyses. Multivariable analysis models were used to calculate adjusted hazard ratios (aHR) for different p16 and HPV testing methods for overall survival, adjusted for prespecified confounding factors. Findings: Our search returned 13 eligible studies that provided individual data for 13 cohorts of patients with oropharyngeal cancer from the