Head and neck cancer, including tumors in the mouth, tongue, nose, sinuses, throat, and lymph nodes, is caused by two distinct culprits with dramatically different risk factors, according to a study by researchers at Johns Hopkins University.
Heavy tobacco and alcohol use has long been recognized as a cause of head and neck cancer, which affects more than 35,000 people in the United States annually. Since 2000, scientists have also known that human papillomavirus (HPV) infection, a common STD, was linked to certain of these cancers, particularly those in the upper throat and back of the tongue.
The study focused on 240 people diagnosed with head and neck cancer between 2000 and 2006. Almost 40 percent of the patients had an HPV infection but lacked the well-known risk factors for head and neck cancer - tobacco smoking, alcohol use, and poor oral hygiene. The participants with HPV-linked cancer cases had a totally different set of risk factors, including certain sexual behaviors and marijuana use. Among these cases, the sexual factors linked to cancer were the presence of an STD and increasing numbers of lifetime sex partners, including oral sex.
"These are completely different cancers and we need to view them as such," Dr. Maura Gillison, professor of oncology and epidemiology at Johns Hopkins, said of the cancers found in HPV-infected versus non-infected patients. "They just happen to occur in the same place. The risk factors didn't appear to overlap at all, and there didn't appear to be any interaction between them."
Not only were the patient populations different in HPV-positive and HPV-negative head and neck cancer, the tumors appeared different under a microscope, said Gillison. Patients with HPV-linked cancer also tended to respond better to treatment than those who were not infected with the virus, she added.
The study, "Improved Survival of Patients with Human Papillomavirus-Positive Head and Neck Squamous Cell Carcinoma in a Prospective Clinical Trial," was published in the Journal of the National Cancer Institute (2008;100(4):261-269).
03/18/08
UNITED STATES: Factors Behind Head and Neck Cancer Revealed
Source: Reuters(03.11.08):: Will Dunham Courtesy of the CDC National Center for HIV, STD, and TB Prevention