A new study shows that cases of HPV-related oral cancers have increased by about 50% between 2000 and 2012.
Researchers say that the percentage of oral cancers caused by the deadly human papillomavirus has increased significantly and estimate that the infection is responsible for an estimated three-quarters of all such malignancies.
The cross-Canada study, published Monday in the Canadian Medical Association Journal, looked at data from specialized cancer centres in British Columbia, Alberta, Ontario and Nova Scotia to determine the rates of HPV-related tumors amoung 3,643 patients aged 18 years or older who were diagnosed with squamous cell oropharyngeal cancer between 2000 and 2012.
Statistics from a Canadian Cancer Society report last fall revealed that 1,335 Canadians were diagnosed in 2012 with HPV-related oropharyngeal cancer and 372 died from the disease.
Majority of Incidences Related to Oral Sex
HPV is the most prevalent sexually transmitted infection worldwide. Most people never develop symptoms and the infection resolves on its own within about two years. However, in some people, the infection can persist, leading to cervical cancer in women, penile cancer in men and oropharyngeal cancer in both sexes.
In addition, most cases of HPV-related oral cancer are linked to oral sex and about 85 per cent of the cases in the CMAJ study were men.
Researchers say that although some centres in Canada regularly test oral tumours to determine their HPV status, such tests are not consistent across Canada.
Historically, physicians tended to reserve tumour testing for cases most likely to be caused by HPV, which were younger males with no history of smoking and with light alcohol consumption, to avoid unnecessary burdens on pathology labs.
HPV Immunization will be made available for boys in all 10 Provinces
Researchers indicate that males tend to have a weaker immune response to HPV than females, which may explain the higher incidence of this virus in men.
HPV vaccinations given to young people before they become sexually active may prevent infection, and the researchers say both boys and girls should be inoculated.
Currently, only six provinces provide HPV immunization to Grade 6 boys as well as girls, while the other four provinces plan to add males to vaccination programs this fall.