Circulating human papillomavirus DNA as a marker for disease extent and recurrence among patients with oropharyngeal cancer.

BACKGROUND: Circulating Epstein-Barr virus DNA is a predictor of disease recurrence in patients with nasopharyngeal carcinoma. Circulating human papillomavirus (HPV) DNA has been detected in the sera of some patients with HPV-positive squamous cell carcinoma of the oropharynx (OPC). The goal of the current study was to determine whether pretreatment serum HPV DNA is a useful biomarker for disease recurrence in patients with HPV-positive OPC.
METHODS: The study included patients with newly diagnosed, previously untreated OPC. Tumor HPV status was determined by polymerase chain reaction; serum HPV DNA was detected using real-time polymerase chain reaction. Differences in clinical characteristics between patients who were positive and negative for pretreatment serum HPV DNA were described using standard descriptive statistical methods. Kaplan-Meier curves were generated and log-rank tests were used to detect statistically significant differences in progression-free survival (PFS).
RESULTS: A total of 262 patients were included. Patients with high N category and those with TNM stage IV disease were found to have higher rates of detectable pretreatment serum HPV DNA. Patients with HPV-positive tumors had better PFS than patients with HPV-negative tumors. Among patients with HPV-positive tumors, those who were negative for pretreatment serum HPV DNA had better PFS than those who were positive for pretreatment serum HPV DNA, but this result was not statistically significant.
CONCLUSIONS: Pretreatment serum HPV DNA was associated with higher N category and overall disease stage. However, pretreatment serum HPV DNA does not appear to have clinical usefulness as a marker for disease recurrence among patients with OPC.