Human papillomavirus (HPV), which causes cervical, vaginal and anal cancers, has long been implicated in the development of oropharyngeal cancer, or throat cancer. The most recent demonstration of that came on May 10 in a study published in the New England Journal of Medicine.
The study was conducted at Johns Hopkins University from 2000 to 2005 and involved 100 persons with throat cancer. It found that 72 percent of the tumors contained HPV-16 DNA one of the most common of the more than 100 types of HPV which is responsible for the largest number of cancers in other tissue.
The cancer was significantly more likely to occur in men than women (86 percent vs. 14 percent). The factors most clearly associated with its occurrence were a larger number of sexual partners and engaging in oral-vaginal sex.
The study could not rule out the possibility that the virus could be spread through direct mouth-to-mouth contact or by other means.
Only 8 percent of the study participants acknowledged ever having had sex with a partner of the same sex, and 87 percent were non-Hispanic whites making it difficult to say with certainty that the findings apply to persons other than white heterosexual males, researchers said.
However, the biological ways that HPV-16 is transmitted and develops into cancer in other tissues does not appear to differ by sex, race or ethnicity.
A history of heavy use of tobacco, alcohol or marijuana also was associated with the development of throat cancer. However, there did not appear to be a synergy between use of these substances and infection with HPV-16.
This led the researchers to suggest that there are “two distinct pathways for the development of oropharyngeal cancer.”
Experts say that oropharyngeal cancer is rare, with an estimated 120,000 cases a year believed to occur among 6 billion people worldwide.
Gardasil, the recently approved vaccine against HPV, is extremely effective at preventing vaginal and cervical cancer. It is being evaluated in the prevention of oropharyngeal cancer as well.
Researchers say there is no biological reason why Gardasil should not be as effective in preventing throat cancer as it is in other cancers, and the study’s authors said this provides yet another rationale for vaccinating boys as well as girls with the vaccine.
This article appeared in the Dallas Voice print edition, May 25, 2007.