(Canadian Press) — The proportion of oral cancers caused by the human papillomavirus has risen significantly in Canada, say researchers, who suggest the infection is now behind an estimated three-quarters of all such malignancies.

In a cross-Canada study, published Monday in the Canadian Medical Association Journal, the researchers found the incidence of HPV-related oropharyngeal cancers increased by about 50 per cent between 2000 and 2012.

“It’s a snapshot of looking at the disease burden and the time trend to see how the speed of the increase of this disease (is changing),” said co-author Sophie Huang, a research radiation therapist at Princess Margaret Cancer Centre in Toronto.

Researchers looked at data from specialized cancer centres in British Columbia, Alberta, Ontario and Nova Scotia to determine rates of HPV-related tumours among 3,643 patients aged 18 years or older who had been diagnosed with squamous cell oropharyngeal cancer between 2000 and 2012.

“In 2000, the proportion of throat cancer caused by HPV was estimated at 47 per cent,” said Huang. “But in 2012, the proportion became 74 per cent … about a 50 per cent increase.”

Statistics from a Canadian Cancer Society report last fall showed 1,335 Canadians were diagnosed in 2012 with HPV-related oropharyngeal cancer and 372 died from the disease.