Have Changing Sexual Habits Led to More HPV-Related Cancers?

The combined incidence of all cancers has been declining slightly, so it’s a surprise to learn that one type, oropharyngeal cancer (most particularly cancer of the tonsils and tongue base) has been on the rise. The culprit appears to be the human papillomavirus (HPV), the same virus responsible for cervical cancer.

According to a study in the Journal of Clinical Oncology, between 1973 and 2004, HPV-related oral cancers among people in their 40s and 50s increased significantly. Statistics from the Centers for Disease Control and Prevention show that there were 7,400 cancers of the oropharynx and oral cavity each year between 1998 and 2003 that may be related to HPV.

Not only has incidence of these types of oral cancer increased, it now appears that they are becoming more common among women than previously, when mostly men were affected. “Ten years ago, the typical patient with oropharyngeal cancer was 70 years old and a heavy smoker and drinker, ” says Robert Haddad, MD, clinical director of the Head and Neck Oncology Program at the Dana-Farber Cancer Institute in Boston. “Over the past decade, we’ve seen a different pattern emerge with an increased number of oropharyngeal cancer in both men and women, in their late 30s or early 40s, who don’t smoke or drink.”

LOOKING FOR A CAUSE

“We had to ask why patients without typical risk factors were getting oral cancers. It was very unusual,” says Dr. Haddad. Analysis of the biopsy specimens revealed the presence of HPV in 50% to 60% of the cases. Dr. Haddad believes that a possible reason behind the growing incidence of oropharyngeal cancer may be an increase in oral sex among young people, who see it as a form of “safe sex.”

It’s known that the sexually transmitted HPV virus has become more common in young adults after they become sexually active, though it takes a long time for HPV-linked cancers to develop. Infection with the virus doesn’t mean cancer is sure to follow — in fact, it usually doesn’t. In most people, the body will clear an HPV infection in two years, according to the American Cancer Society. Still, a recent New England Journal of Medicine article reported that people infected with a particular type, HPV-16, were 32 times more likely to develop oropharyngeal cancer than those who did not have the virus (though the absolute risk remains low).

Other cancers are also linked to the HPV virus, including anal, vulvar, penile and vaginal cancers, although in lower rates than cervical and oropharyngeal cancer. According to the CDC, there were 25,000 HPV-related cases of these cancers diagnosed each year during 1998 to 2003.

PREVENTION IS KEY

One weapon, according to Dr. Haddad, is Gardasil, the vaccine developed to prevent cervical cancer, which is being administered to females, typically ages 11 to 26. Dr. Haddad believes boys would benefit too, noting “there’s a clear need to protect males, as well,” though the vaccine hasn’t yet been tested on boys. Indeed, the number of HPV-related cancers in men demonstrates that men should not be overlooked. However, many question whether adequate short- and long-term safety testing of this vaccine has been done.

“The HPV virus is a major health problem,” warns Dr. Haddad. “People need to be aware that infection with HPV carries a small but definite risk for multiple types of cancer.”