HPV-related cancers of the anus and the base of the tongue and tonsils have increased over the past 35 years, especially among men and women younger than 45, the Canadian researchers report.
"The increases in the incidence of oropharyngeal [throat] cancer among younger men and of anal cancer among younger women are disturbing, because there are no screening programs for early detection of these cancers," said study co-author Dr. Lorraine Shack, an assistant professor of oncology at the University of Calgary's Cumming School of Medicine.
It's estimated that HPV, a sexually transmitted virus, may cause 5.2 percent of all cancers around the world. The link between HPV and cancers of the oropharynx and anal cancer was only recently confirmed, according to background information in the study, published recently in CMAJ Open.
The researchers used the Alberta Cancer Registry to analyze trends in HPV-related cancers diagnosed between 1975 and 2009. They identified 8,120 cases.
Of these, 56 percent were cervical cancers and 18 percent were oropharyngeal cancers -- cancers in the back of the mouth or throat.
Although most cases of HPV-related cancers involved people between the ages of 55 and 74, the greatest percentage increase in oropharyngeal cancers involved men younger than 45.
Meanwhile, anal cancer among women doubled, going from 0.7 to 1.5 per 100,000 people.
Alberta's publicly funded HPV vaccine program, introduced in 2008 and offered to all 5th grade girls, is expanding to include 5th grade boys in September.
In the United States, all boys and girls aged 11 or 12 should get vaccinated, according to the U.S. Centers for Disease Control and Prevention.
Vaccination and education programs are necessary, said Dr. Harold Lau, a clinical associate professor of oncology at the University of Calgary.
"To have a large impact on the prevention of these HPV-associated cancers, vaccination programs should be considered for males as well as females, as has now been done in Alberta," said Lau, a co-author of the study. "Both oropharyngeal and anal cancers are associated with substantial side effects when treated; therefore, education and prevention programs, including the HPV vaccination program, are urgently required."
The U.S. Centers for Disease Control and Prevention provides more information on HPV-related cancers.