HPV Infection Increases Survival in Oropharyngeal Cancers

Previous studies have found oral human papillomavirus (HPV) infection to be a strong risk factor for oropharyngeal cancer. Now, the largest and most definitive study to date has confirmed these findings, suggesting HPV-positive oropharyngeal cancers have better outcomes than HPV-negative cancers, independent of other risk factors, such as age and smoking history.

The study included 206 patients with oropharyngeal cancers containing HPV, the majority of which were HPV subtype 16, and 117 patients with HPV-negative disease. Patients were treated with a combination of radiation and chemotherapy. After 2 years, 87.9% of patients with HPV-positive disease were still alive compared with 65.8% of those with HPV-negative disease. Patients with HPV infection also had a longer progression-free survival and a smaller incidence of secondary primary cancers compared with their HPV-negative counterparts, with rates of 71.8% and 50.4%, and 9.0% and 18.5%, respectively.

Researchers aren't sure why HPV-positive oropharyngeal cancers have better outcomes, but noted that patients with these cancers tend to be younger, have a smaller tumor at diagnosis, and are less likely to smoke than HPV-negative patients. According to Maura Gillison, MD, PhD, professor of medicine, epidemiology, and otolaryngology, Ohio State University, and the lead investigator of the study, “these data provide further evidence that HPV-positive oropharyngeal cancer is a distinct disease entity.” She noted that the findings of this study and others are changing how clinical trials are designed, with investigators studying head and neck cancers now stratifying patients according to their HPV status. Studies are currently being designed to determine if the HPV vaccine may prevent the occurrence of HPV-positive oropharyngeal cancers.