HPV-16 infection predicts treatment outcome in oropharyngeal squamous cell carcinoma

Abstract

Objective: To determine if patients with human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPSCC) treated with chemoradiation have improved outcomes. Study Design: A retrospective search was used to identify patients with OPSCC treated with concurrent chemoradiation. Pretreatment biopsy specimens were tested for HPV-16 infection and p16 expression. Methods: Forty-four patients with OPSCC treated with concurrent chemotherapy and intensity-modulated radiation therapy were identified. Eligibility criteria included a minimum two years of follow-up, or biopsy-proven recurrence. In situ hybridization was applied to archival tumor specimens, with HPV-16-positive status defined as positive staining of tumor cell nuclei. p16 expression was assessed by immunohistochemistry. Results: Twenty-seven tumors (61%) were positive for HPV-16 and 29 tumors (66%) expressed p16. HPV-16 infection was highly correlated with p16 expression ( P < 10−7). Three-year disease-free and overall survival for all patients was 66 percent and 79 percent respectively. Patients with tumors infected with HPV-16 had improved overall (OS) and disease-free survival (DFS) after chemoradiation (OS: hazard ratio [HR] = 0.21, P = 0.01; DFS: HR = 0.30, P = 0.02). Conclusion: Patients with OPSCC tumors that are infected with HPV-16 have improved survival after treatment with concurrent chemoradiation.