Sore throat for a very long time could be an early precursor of a sexually transmitted virus that is fueling a rise in oral cancer suggest researchers. Between 1988 and 2004, head, neck and throat cancers that tested positive for the human papilloma virus rose an astounding 225 percent, according to a new study.
The Human Papilloma Virus or HPV is best known for causing cervical cancer. But it can cause cancer in the upper throat, too, and a new study says HPV-positive tumors now account for a majority of these cases of what is called oropharyngeal cancer. The researchers from Ohio State University and the National Cancer Institute report Monday that if this trend continues, that type of oral cancer will become the nation's main HPV-related cancer within the decade, surpassing cervical cancer.
Dr. Amy Chen of the American Cancer Society and Emory University, who wasn't part of the new research said, “There is an urgency to try to figure out how to prevent this.” While women sometimes get oral cancer caused by the HPV, the risk is greatest and rising among men, researchers reported in the Journal of Clinical Oncology. They add that vaccine given to girls and young women may also protect against cervical cancer also might protect against oral HPV.
HPV vaccination is approved for boys to prevent genital warts and anal cancer, additional problems caused by human papillomavirus. But protection against oral HPV hasn't been studied in either gender, says Dr. Maura Gillison, a head-and-neck cancer specialist at Ohio State and senior author of the new research. That's important, because it's possible to have HPV in one part of the body but not the other, she says.
A spokeswoman for Merck & Co., maker of the HPV vaccine Gardasil, said the company has no plans for an oral cancer study. Monday's research was funded by the NCI and Ohio State. Gillison has been a consultant to Merck.
The new study took a closer look, tracking HPV over time by directly testing tumor tissue from 271 patients that had been stored in cancer registries in Hawaii, Iowa and Los Angeles. The proportion that were HPV-positive rose from just 16 percent in the late 1980s to nearly 73 percent by the early 2000s. Translate that to the overall population, and the researchers concluded that incidence rates of the HPV-positive tumors more than tripled while HPV-negative tumors dropped by half.
The study authors collected their data from the three states that participate in a government cancer incidence database for oropharyngeal cancer: Hawaii, Iowa and Louisiana. They determined the HPV status of 271 tumors and found that the prevalence of HPV-related cancers increased from 16.3 percent during 1984-1988 to 71.7 percent from 2000 to 2004.
An accompanying commentary noted that “we can expect some 10,000 to 15,000 patients with (the cancers) per year in the United States, with the great majority having HPV-positive (cancers)."
While HPV is the most common sexually transmitted infection, studies show women's bodies usually clear the virus from the cervix quickly; only an infection that persists for years is a cancer risk. It's not known if oral HPV acts similarly or even is as common.
Nor is it clear if oral sex is the only way it's transmitted, cautions Dr. Gregory Masters of the American Society for Clinical Oncology, an oncologist at Delaware's Helen Graham Cancer Center.
“We believe that sexual habits have changed, and that there is an increase in sexual activity earlier on in life, with an exchange of many more sex partners in general,” said Dr. Tina Dalianis, a professor at the Karolinska Institute in Sweden.
In the recent controversy over comments made by presidential candidate Michele Bachmann about the HPV vaccine, the focus was squarely on young women and cervical cancer. But HPV, mainly a strain called HPV-16, also causes oropharyngeal and anal cancer, a fact not often publicized because medical organizations, the government, and academics would rather not step into any debates about sex practices.
The commentary accompanying the study suggested, “patients should be encouraged to minimize behaviors that put them at risk.” That, of course, would mean reducing oral and anal sex. According to the National Survey of Family Growth issued last March by the National Center for Health Statistics, about 90 percent of both men and women have engaged in oral sex with an opposite-sex partner, and 36 percent of women and 44 percent of men have had anal sex. Statistics like that, and the new study’s findings on head and neck cancer rates may combine to make a broader vaccine recommendation more urgent.
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