Human papilloma virus (HPV) linked to increased head and neck cancers

Columbus, Ohio (TDN) — A new study in the Journal of Clinical Oncology has determined that the human papilloma virus (HPV) is contributing to the growing number of head and neck cancers in the United States.

Cancer of the head and neck.

The study found that cancers of the tonsil, back of the mouth (throat) and base of the tongue ( oropharyngeal cancers) has been on the rise since the mid-1980s and continues to increase. One reason given for the increase is the number of people having oral sex resulting in oral human papilloma virus exposure.

According to the study, these cancers are caused by tobacco and alcohol and the sexually transmitted virus, HPV, with HPV thought to account for 70% of all oropharyngeal cancers.

The findings of the latest study were based on the testing of cancer tissue samples from almost 6,000 patients in Hawaii, Iowa and Los Angeles between 1984 and 2004. They found the HPV-positive cancers increased 225% while HPV-negative oropharynx cancers dropped 50%–most likely because of a reduction in smoking and tobacco use.

An interesting outcome of the study was that patients with HPV-positive cancers live longer. According to principal investigator Dr. Anil Chaturvedi of the National Cancer Institute, "the precise reasons for the survival benefits are not clear, but tumors in HPV-positive patients tend to have less genetic damage. Because of that, they are more responsive to cancer therapies like radiation treatment." HPV-positive patients have an approximate 60% reduction in risk of death after their diagnosis when compared to HPV-negative patients.

The researchers noted that about 95% of the HPV-positive oropharynx cancers were caused by HPV16. In 2006 Merck & Co. introduced the Gardasil vaccine for use in females ages 9-26 to help prevent cervical cancer and genital warts, but it has not been recommended for use in preventing HPV-associated cancers. The vaccine is however targeted at combating the HPV16 strain and has also been approved for males 9-26 to reduce the risk of genital warts.

Another vaccine targeted at the HPV16 strain is the Cervarix vaccine, which was introduced in 2009 by GlaxoSmithKline for use in females 10-25 to help prevent cervical cancer.

There were almost 35,000 new cases of oral and oropharyngeal cancers this year, according to the American Cancer Society. While about 7,000 Americans will die this year, death rates associated with these cancers has actually been declining over the last 30 plus years.

Researchers predict that the burden of invasive HPV-caused cancers will shift from women to men in the US, largely due to the rise of HPV-positive oropharynx cancers among men.