HPV-Induced Oropharyngeal Squamous Cell Carcinomas in Brazil: Prevalence, Trend, Clinical, and Epidemiologic Characterization.

BACKGROUND: Tobacco or human papillomavirus (HPV)-related oropharyngeal squamous cell carcinomas (OPSCC) represent different clinical and epidemiologic entities. This study investigated the prevalence of HPV-positive and HPV-negative OPSCC in a reference cancer hospital in Brazil and its association with clinical and demographic data, as well as its impact on overall survival. METHODS: HPV infection was determined by p16-IHC in pre-treatment formalin-fixed paraffin-embedded samples from all patients with OPSCC diagnosed at Barretos Cancer Hospital between 2008 and 2018. The prevalence of HPV-positive cases and its temporal trend was assessed, and the association of clinical and demographic data with HPV infection and the impact on patient overall survival was evaluated. RESULTS: A total of 797 patients with OPSCC were included in the study. The prevalence of HPV-associated tumors in the period was 20.6% [95% confidence interval, 17.5-24.0] with a significant trend for increase of HPV-positive cases over the years (annual percentage change = 12.87). In a multivariate analysis, the variables gender, level of education, smoking, tumor sublocation, region of Brazil, and tumor staging had a significant impact in HPV positivity, and a greater overall survival (OS) was observed in HPV-positive patients (5-year OS: 47.9% vs. 22.0%; P = 0.0001). CONCLUSIONS: This study represents the largest cohort of Brazilian patients with OPSCC characterized according to HPV status. We report significant differences in demographics and clinical presentation according to HPV status, and an increasing trend in prevalence for HPV-induced tumors. IMPACT: These findings can potentially contribute to a better stratification and management of patients as well as assist in prevention strategies.

Human Papillomavirus DNA Detection by Droplet Digital PCR in Formalin-Fixed Paraffin-Embedded Tumor Tissue from Oropharyngeal Squamous Cell Carcinoma Patients.

INTRODUCTION: High-risk human papillomavirus infection impacts staging and prognosis of oropharyngeal squamous cell carcinomas (OPSCCs). Determination of HPV status in tumor tissue by p16-immunohistochemistry (p16-IHC) can be challenging; therefore, complementary methodologies could be useful in a clinical setting. OBJECTIVE: To test for accuracy and clinical relevance of HPV-DNA detection in formalin-fixed and paraffin-embedded (FFPE) tumor samples by droplet digital PCR (ddPCR). MATERIALS AND METHODS: Fifty OPSCCs were tested for p16-IHC status followed by HPV-16/18 DNA detection/quantification in FFPE-recovered DNA using ddPCR. Accuracy for HPV status determination and association with patient information were also evaluated. RESULTS: 32.0% (16/50) of the cases were p16-IHC positive (p16 +), 42.0% (21/50) had detectable levels of HPV-16 DNA, and none were positive for HPV-18 DNA. A higher median viral load of HPV-16 DNA was observed in p16 + cases (p < 0.0001). Concordance between p16-IHC and HPV-16 DNA ranged from 78.0 to 86.0% and accuracy rates were between 78.0 and 86.0%. P16-IHC and HPV-16 DNA detection was associated with gender, smoking status, and tumor subsite, while only HPV-16 DNA was associated with cT stage. The combination of HPV positivity by p16-IHC and ddPCR showed higher overall survival rates in comparison with p16 + /HPV-DNA- and p16 - /HPV-DNA- results. CONCLUSIONS: Type-specific HPV-DNA detection by ddPCR is highly specific but moderately sensitive for the determination of HPV status and showed clinical relevance, mainly when associated with p16-IHC status. Results highlight the importance of performing HPV-DNA testing in combination with p16-IHC for proper identification of HPV-associated OPSCC and to improve clinical management of OPSCC patients.