Incidence Trends for Human Papillomavirus-Related (HPV-R) and Unrelated (HPV-U) Head and Neck Squamous Cell Carcinoma (HNSCC) in the United States (US)
With the recent approval of a vaccine for HPV and a second approval pending, there has been much discussion of how these vaccines may affect other cancers in addition to cervical cancer. Approximately 405,000 cases of head and neck cancers are diagnosed annually worldwide and approximately 40,000 are diagnosed in the U.S. annually, with about 75% being related to alcohol and tobacco use. The grouping of head and neck cancers contains many different tumor types, some of which have been shown to be related to HPV infection. These include SCC of the base of tongue (BOT), tonsil, and the oropharynx; whereas cancers of the lip, tongue, gum, floor of mouth, palate, and pharynx are not typically related to HPV.
The number of cases of oropharyngeal cancer has been increasing and due to oropharyngeal cancer's association with HPV, this implies an increasing rate of HPV infection. In comparison, oral cavity cancers, which are associated with tobacco and alcohol use are declining, which may reflect a decrease in tobacco use. The purpose of this study was to investigate what influence HPV infection has on the number of cases and survival of patients with HNSCC.
The researchers found a steady increase in the number of cases related to HPV from 1973-2003. This was most commonly seen in white males, whereas rates in African Americans and women did not increase. Rates of HPV unrelated tumors decreased over the same time period. They also found that HPV related tumors were more sensitive to radiation and appeared in younger patients (61.1 versus 64.5 years old). The study looked back at medical records (called a retrospective study), which is not as reliable as looking at cases in real time. Because of the restrospective design, they could not actually test for HPV in the tumors, which is a limitation of this study. Nonetheless, it lays the groundwork for future studies in this area, which could lead to changes in treatment.