Aptima HR-HPV Testing of Cytology Specimens Is an Effective Supplement for p16 Staining to Improve Diagnostic Accuracy for HPV-Related Oropharyngeal Squamous Cell Carcinoma

Introduction: Regarding a small proportion of oropharyngeal squamous cell carcinoma (OPSCC) patients who tested p16-positive but human papillomavirus (HPV)-negative, we attempted to perform HPV testing to improve the accuracy of HPV detection in OPSCC patients. Methods: We simultaneously performed Aptima HPV testing of cytological specimens and p16 immunohistochemistry (IHC) staining of histologic biopsies from the same cohort of patients with head and neck SCC (HNSCC). The cytological specimens included fine-needle aspiration specimens from patients with enlarged nodes and endoscopic brushing specimens from the primary lesions of patients without enlarged nodes. Cases with discordant results for p16 IHC staining and Aptima HPV testing were reexamined by a third method, RNAscope testing. Results: Sixty patients with HNSCC (39 OPSCC and 21 non-OPSCC) were recruited for examination of HPV status. Among these patients, 28 were p16+/HPV+, 29 were p16-/HPV-, 2 were p16+/HPV-, and 1 was p16-/HPV+. The overall concordance rate between Aptima HPV testing and p16 IHC was 95.0%. Three cases with discordant results for these two methods were reexamined by RNAscope testing, and all were confirmed to be HPV negative. The prevalence of HPV in OPSCC and non-OPSCC patients was 61.5% (24/39) and 19.0% (4/21), respectively. The sensitivity and negative predictive values of Aptima HPV testing and p16 IHC were consistent at 100%, while the specificity and positive predictive values were 96.9% and 96.6% versus 93.8% and 93.3%, respectively. Additionally, 30 OPSCCs were simultaneously examined and diagnosed by both brush cytology and biopsy pathology; six of these SCCs were underdiagnosed by histopathology but accurately diagnosed by supplemental brush cytology. Conclusion: Aptima HPV testing of cytology specimens can be used as an adjuvant examination to identify false-positive OPSCC patients after p16 IHC of biopsies, while brush cytology may be a supplemental method for the histologic diagnosis of malignant oropharyngeal tumors.