It’s long been thought by scientists that carcinogens in tobacco were the main cause of head and neck cancer. Only smokers had to worry about getting this type of cancer.
No longer is this the case.
Researcher Allen M. Chen and his colleagues within the UC Davis radiation oncology and otolaryngology departments recently discovered a new cause of head and neck cancer: human papillomavirus (HPV). The strain of HPV that causes head and neck cancer is a sexually transmitted disease that is passed primarily through oral sex.
“Within the last five to 10 years, we are starting to see an epidemic of HPV head and neck cancers for people who have never smoked in their lives,” Chen said. “The modes of transmission and how it is spread are still largely unknown, but there has been research implicating oral sex as the most common source.”
Chen conducted an experiment testing the effectiveness of radiation therapy on smokers versus non-smokers who had head and neck cancer. The results concluded that radiation therapy on non-smokers had a much lower rate of death and recurrence of disease than smokers. Also, 82 percent of non-smokers who had cancer from HPV had no signs of the disease three years later, compared to 65 percent of smokers.
Andrew Vaughan, a researcher in the UC Davis department of oncology, spoke of the HPV epidemic in relation to treating different causes of cancer.
“Head and neck cancer was historically found more often with ‘smokers and drinkers,'” Vaughan said. “More recently, head and neck cancers have been increasingly observed in individuals that do not smoke or drink but who have HPV within their tumors.”
Vaughan said the effectiveness of radiation treatments between the smokers and non-smokers was due to the causes of their cancers. The possible reason radiation treatment works better on non-smokers could be because radiation is more effective on HPV than on tobacco-induced tumors.
“In terms of understanding the disease, it is best to think of ‘smoker’ and ‘HPV’ head and neck cancer as two different diseases,” Vaughan said. “This is on the way to being accepted clinically with different radiation treatments being considered for each type.”
The effects of HPV on the cells of your body are less severe than with smoking, causing a much milder form of the cancer. This could explain why radiation therapy more easily kills cells damaged by HPV.
HPV is becoming more common among sexually active teenagers and adults. While only women get cervical cancer form HPV, both men and women can get head and neck cancer.
Chen also stressed the importance of getting vaccinated for HPV in order to prevent the danger of HPV turning into head and neck cancer.
The next steps in head and neck cancer research are identifying the biological or genetic components that would explain the increased effectiveness of radiation on the head and neck cancer of non-smokers.
CAMMIE ROLLE can be reached at science@theaggie.org.
