October 5, 2011
The incidence of HPV-positive oropharyngeal cancers has risen over time, and these now account for the majority of such cancers, according to new study.
The overall incidence of oropharyngeal cancers has risen 28 percent since 1988, to nearly 10,000 new cases annually, even as other head and neck cancers have declined. Incidence among women, who account for about one in four cases, is holding steady, while it is rising among men, said study leader Dr. Maura Gillison, a head-and-neck cancer specialist at Ohio State University.
The new study directly tested tumor tissue from 271 oropharyngeal cancer patients whose samples were stored in cancer registries in Hawaii, Iowa, and Los Angeles. The proportion that was HPV-positive rose from 16 percent in the late 1980s to nearly 73 percent by the early 2000s.
That would translate to incidence rates of HPV-positive tumors more than tripling in the overall population, while HPV-negative tumors dropped by half. The shift perhaps reflects changes in smoking behaviors and increased oral sex and oral HPV exposure over time, the study suggested.
The lower proportion of HPV-positive oral cancers among women raises questions about gender differences in sexual behavior and whether HPV lingers longer in men. However, it is not clear whether oral sex is the only way HPV is being transmitted, cautioned Dr. Gregory Masters of the American Society for Clinical Oncology, who was not involved in the study.
The full report, "Human Papillomavirus and Rising Oropharyngeal Cancer Incidence in the United States," was published online ahead of the print edition of Journal of Clinical Oncology (2011;doi:10.1200/JCO.2011.36.4596).