September 7, 2010
Infection with human papillomavirus has become a dominant risk factor for oral cancers in some countries as smoking rates decline, researchers say. Oral sex is believed to be the transmission mode, with one Canadian expert identifying the advent of oral contraceptives, and the concurrent rise of sexual freedom, as the tipping point for the increase in HPV-related oral cancers.
"HPV has been around for ages, but the use of oral contraceptives starting in the 1960s and '70s led to an increase in incidence of [STDs]," said Dr. John Hay, a radiation oncologist at the British Columbia Cancer Agency.
In the 1970s, 23 percent of oral cancers were HPV-linked, according to a Swedish study. By 2006, that had climbed to 93 percent. A U.S. study showed the rate doubling in 10 years, with 80 percent of oral cancer biopsies HPV-positive.
The five-year survival rate for HPV-related oral cancer is about 75 percent, compared with about half that for smoking-related oral cancer.
Under the current rate of HPV vaccine uptake, it could take a decade before rates of both cervical and oral cancers have been reduced, Hay said. At this point, the vaccine is approved for boys but not recommended for them, so "only half" the population is protected against strains of HPV that cause both cervical and oral cancer, he said.
"It would make sense to vaccinate both girls and boys," Hay said.
09.03.2010; Pamela Fayerman
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