Source: Jada.org

An increase in the incidence and survival of oropharyngeal cancer in the United States since 1984 can be attributed to the human papilloma-virus (HPV) infection, say researchers in an article published online Oct. 3 in Journal of Clinical Oncology.

The results of previous studies have shown that oropharyngeal cancers can be divided into two separate diseases with distinct causes: HPV-negative cancers, which are associated with tobacco and alcohol use; and HPV-positive cancers, which are linked to certain types of HPV, a sexually transmitted virus.

Patients with HPV-positive oropharyngeal cancer tend to be younger than and to have better survival rates than patients with HPV-negative cancer.

To determine HPV infection’s role, researchers led by Anil K. Chaturvedi, PhD, National Cancer Institute, National Institutes of Health, Bethesda, Md., tested for HPV infection 271 archived samples of cancerous oropharyngeal tissue collected between 1984 and 2004 at three population-based cancer registries located in Hawaii, Iowa and Los Angeles in the National Cancer Institute’s Surveillance, Epidemiology and End Results Residual Tissue Repositories Program. By using a variety of molecular assays, researchers found that the proportion of oropharyngeal cancers that were HPV-positive—particularly among men—increased over time, from 16.3 percent for cancers diagnosed from 1984 to 1989 to 72.7 percent for cancers diagnosed from 2000 to 2004. They also found that the incidence of HPV-negative oropharyngeal cancers declined by 50 percent between 1988 and 2004, likely due to declines in smoking and tobacco use.

According to senior author Maura Gillison, MD, PhD, a professor of medicine at The Ohio State University Comprehensive Cancer Center in Columbus, the study’s results suggest that if these trends continue, HPV-positive oropharyngeal cancer will become the major form of head and neck cancer and the leading HPV-associated cancer in the United States by 2020, surpassing cervical cancer.

“These increases may reflect increases in sexual behavior, including increases in oral sex,” said Dr. Gillison. She noted that approximately 90 to 95 percent of HPV-positive oropharyngeal cancers were caused by one HPV type—HPV16, which is targeted by vaccines for cervical cancer.

“With HPV vaccines, we have a great opportunity to potentially prevent oropharynx cancers in future generations, including in boys and men, but studies need to be done to evaluate the efficacy of HPV vaccines in preventing oral HPV infections,” Dr. Gillison said.

This study was supported by the Intramural Research Program of the National Cancer Institute, National Institutes of Health; The James Comprehensive Cancer Center; The Ohio State University; and the Oral Cancer Foundation.