BOSTON, MA — The sexually transmitted virus that can cause cervical cancer also sharply increases the risk of throat cancer among people infected through oral sex, a new study released through the New England Journal Of Medicine says.The study, involving 300 subjects with and without throat cancer, found that those infected with the human papillomavirus (HPV) were 32 times more likely to develop one form of oral cancer than those free of the virus. Although previous research had indicated that the virus caused oral cancer, the new study is the first to definitively establish the link, researchers said.
“It makes it absolutely clear that oral HPV infection is a risk factor,” said Maura Gillison, an assistant professor of oncology and epidemiology at the Johns Hopkins Medical Institutions in Baltimore, who led the study.
The findings could help explain why oral cancer rates have been increasing in recent years, particularly among younger people and those who are not smokers or heavy drinkers, which had long been the primary at-risk groups, the study reports. Researchers looked at 100 newly formed throat cancers and found HPV in nearly three quarters of them.
The findings provide new evidence that oral sex is not the safe sex many have believed it to be.
“Many adolescents, and adults too, say they engage in oral sex as a less risky type of sex,” said Mark Schuster of the University of California, Los Angeles, noting that herpes, syphilis, gonorrhea, HIV and other sexually transmitted infections also spread through oral sex. “What this article and others show is you absolutely can get serious sexually transmitted diseases through oral sex.”
The findings could also provide new ammo for those advocating wide use of a new vaccine that protects against HPV. Even though the vaccine has not been tested specifically to see if it reduces the risk of oral cancer, it is designed to protect against the type of HPV associated with the cancer.
“This adds more data that HPV is an important cause of cancer and that this is an important vaccine,” said Joseph Bocchini, who chairs the American Academy of Pediatrics’s committee on infectious diseases.
The type of oral cancer linked to HPV hits about 11,000 Americans a year. This is about the same as the number of women diagnosed with cervical cancer.
This study could also spur calls to vaccinate both boys and girls because oral cancer strikes both.
Proponents of the vaccine have been for mandatory vaccination of girl children but opponents say the vaccine may encourage sexual activity and that the vaccine is too new to be sure that it is safe and its effectiveness is long lasting.
In the medical study, regardless of whether they were infected, anyone who had had between one and five oral sex partners was 3.8 times more likely to have the cancer, whereas those who had had more than six oral sex partners were 8.6 times more likely.
Meanwhile, there’s doubt as to whether the vaccine is really that effective.
Although the vaccine, marketed under the name Gardasil, blocked about 100-percent of infections by the two HPV strains it targets, it reduced the incidence of cancer precursors by only 17-percent overall.
Part of the reason was that many of the teenage girls and young women in the three-year study had already been exposed to the virus, according to the report in the New England Journal of Medicine. This has given doctors credence in the idea that girls should be given the vaccine as children, before they become sexually active.
In an editorial in the same issue of the journal, Dr. George F. Sawaya and Dr. Karen Smith-McCune of the University of California San Francisco called the benefits of the highly touted vaccine “modest,” and said that young women and their parents should take “a cautious approach” to vaccination because of the many unanswered questions about its efficacy.
Overall, the new results of studies of the vaccine indicate that the vaccine is not all of what it was initially cracked up to be. The findings show that 129 women would have to be vaccinated to prevent just one precancerous lesion.
When doctors give the vaccine to patients, they think that ” ‘I am protected against everything,’ and that’s just not true,” said Dr. Diane M. Harper of Dartmouth University, who helped design a related Merck-funded HPV study in the journal in an interview with the health media. Merck is the manufacturer of Gardacil.
Harper is still in favor of giving Gardasil to girls because it is safe and it “protects against the main HPV bad actors,” but she argued that neither doctors nor women should be lulled into a false sense of security by the shots.
“I don’t think this is the gun that is going to take cervical cancer off the map,” Harper added.
