Oral sex, throat cancer and HPV vaccines
More men may get throat cancer from having oral sex than from smoking due to HPV, or human papillomavirus. Of 271 throat-tumor samples collected between 1984 and 2004, the percentage of oral cancer linked to HPV jumped to almost 73 percent from about 16 percent, according to a new study in the Journal of Clinical Oncology.
Another interesting finding - by 2020, throat tumors linked to HPV, which mostly affected men, will become more common than cervical cancer caused by the virus. And the finding that HPV may cause throat cancer could increase pressure on Merck, which already sells the Gardasil vaccine to combat the HPV virus in young women and genital warts in young men, to conduct large clinical trials.
In their piece, the researchers write that their findings make a case for evaluating vaccine effectiveness to prevent squamous cell carcinoma, or OSCC, “particularly given the unavailability of screening” for the malignancy. An accompanying editorial notes that the number of cases is expected to grow by 10,000 to 15,000 annually in the US.
“The burden of cancer caused by HPV is going to shift from women to men in this decade,” Maura Gillison, the lead author and an oncologist at Ohio State University, tells Bloomberg News. “What we believe is happening is that the number of sexual partners and exposure to HPV has risen over that same time period.”
The study forecast that throat cancer linked to HPV can be expected to number about 8,700 cases in the US by 2020, and 7,400 will be among men. By contrast, about 7,700 cases of cervical cancers are projected (here is the study). For this reason, Gillison says more research is needed. Several years ago, she says she worked with Merck, which sells the controversial Gardasil vaccine for HPV, to design a study in men. But after Merck acquired Schering-Plough two years ago, she says the trial “was canceled.”
And what does Merck say? A spokeswoman for the drugmaker tells Bloomberg that a decision was made not to proceed with such a study “due to competing research and business priorities.” As for GlaxoSmithKline, which sells the competing Cervarix vaccine, the drugmaker has “no plans” to conduct such a study, a spokeswoman tells the news service.
The vaccine was approved five years ago to protect against various strains of the human papillomavirus in girls and women ages 9 to 26. HPV can lead to cervical cancer,
Gardasil, you may recall, was approved five years ago to protect against four strains of HPV, which can lead to cervical and other cancers, in girls and women between the ages of 9 and 26 years old. Later, the vaccine was approved in boys and young men in the same age range to combat two HPV strains that can cause genital warts. Glaxo’s Cervarix is approved for preventing HPV in females ages 9 through 25.
Whether Merck or Glaxo R&D execs think twice remains to be seen, of course, but Merck, in particular, has struggled to turn Gardasil into a blockbuster, partly due to controversy over its marketing, parental concerns about premarital sex, side effects and cost. On one hand, there is the high cost of clinical trials. On the other hand, there is the potential to market an HPV vaccine to the larger male population that engages in oral sex (sorry, no data on that).
We should note that several of the authors, including Gillison, have accepted honoria and research funding from Merck, as well as worked as consultants to the drugmaker. However, this is not the first time that HPV vaccines have been suggested for combating the spread of throat cancer traced to oral sex. Last year, researchers wrote in BMJ urging that the vaccines should be used to thwart oral cancers (read here).
Gillison, by the way, was also a co-author of a study published in 2007 in The New England Journal of Medicine that found having a large number of oral or vaginal sex partners was a risk factor for developing throat cancer linked to HPV. And she says the cancer may also be spread by open-mouth kissing. “Nobody paid attention to oral HPV infections until 2007,” she tells Bloomberg. “We are about 15 years behind in the research” compared with the data on cervical cancer and HPV.
Until recently, head and neck cancer mainly occurred in older patients and was associated with tobacco and alcohol use, but the decline in cigarette smoking decline is likely responsible for a drop in oral cancer that is not traced to HPV.
By Ed Silverman
Pharmalot
http://www.pharmalot.com/2011/10/oral-sex-throat-cancer-and-hpv-vaccines/
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