Mouth and throat cancers now represent about a third of cancers induced by HPV in Canada, according to a new report.
The Canadian Cancer Society and Public Health Agency of Canada released their annual report on cancer statistics Wednesday, with a special chapter on cancers linked to the human papilloma virus.
Almost 4,400 Canadians will be diagnosed with HPV-linked cancers this year and about 1,200 die from it annually.
About one third are cervical cancers.
"If you look at the trends there we're seeing that cervical cancer is relatively stable," said Leah Smith, an epidemiologist with the Canadian Cancer Society. "But rates of HPV mouth and throat cancers in males are increasing."
HPV infection is the most common sexually transmitted disease in Canada and the world, the society said.
Most people never even know they have the virus since the infection usually clears within two years without causing physical symptoms. They can pass it on to their partners without knowing, which highlights the importance of prevention.
There is a vaccine to protect against most common types of HPV that cause cancer.
"HPV vaccination is something relatively easy parents can do to protect their children from cancer," Smith said.
The HPV vaccine is offered to girls in all provinces and territories and to boys in Alberta, Manitoba, Nova Scotia, Ontario, P.E.I. and Quebec.
Smith said vaccination policies should reflect that one in three HPV cancers are diagnosed in males. That's why the society is calling on other provinces and territories to expand free vaccination programs to boys.
Canadian men are more than four times more likely to get an HPV mouth or throat cancer than women.
Why that's the case isn't clear, Smith said.
"It does seem that the male immune system is responding differently to HPV infection than the female immune system," Smith said. "What we are seeing is men are more likely to get an oral HPV infection and then once they get the oral HPV infection, are less likely to clear [the infection.] It's the persistence of HPV infection that ultimately lead to cancer."
'My throat closed up'
Terry Patterson, 52, had a persistently sore throat and swollen glands in his neck in fall 2013. A biopsy confirmed that the Waterloo, Ont., man had a malignant growth in his left tonsil. The throat cancer was tied to an aggressive strain of HPV.
"It was a nightmare," Patterson said.
The father of four grown children had 35 days of radiation treatment in Toronto, as well as chemotherapy to prevent recurrence.
"My throat closed up so I couldn't eat," he said, explaining that for months, he received nutrition from a feeding tube inserted in his abdomen. "I lost 45 pounds and got third-degree burns from the radiation."
Patterson, who was recently told he is now cancer-free, encourages parents to have their children vaccinated against HPV. "I don't want anyone to go through what I did."
Leading cause of death in Canada
More generally, cancer is the leading cause of death in Canada, responsible for 30 per cent of all deaths, followed by cardiovascular diseases such as heart disease and stroke, and accidents.
New cancer cases and deaths continue to rise steadily as Canada's population grows and ages, according to a new report.
Current estimates suggest an estimated 202,400 new cases of cancer will be diagnosed in Canada this year and there will be 78,800 deaths from cancer.
Half of new cancer cases will be lung, breast, colorectal and prostate cancer. Of these, lung cancer is the leading cause of cancer death — more than the other three combined.
While the majority of Canadians who develop cancer, 89 per cent, are over 50, cancer was also the leading cause of disease-related death in children under 15 in 2012.
The society said the risk of cancer can also be reduced through measures such as:
- Avoiding smoking: Tobacco is responsible for nearly one-quarter of cancer deaths worldwide, making it the single greatest avoidable risk factor for cancer.
- Following a healthy lifestyle: Eating well, being active and having a healthy body weight can prevent about one-third of the 12 major cancers worldwide, according to the American Institute for Cancer Research and the World Cancer Research Fund.
- Reducing alcohol consumption: Alcohol is a risk factor for many different types of cancer, and the risk of cancer increases with the amount of alcohol consumed.
- Avoiding overexposure to sunlight and not using tanning beds or sun lamps: Limiting time in midday sun, wearing protective clothing, seeking shade and using sunscreen can help reduce the risk of skin cancer while still allowing people to receive the health benefits of sun exposure.
- Preventing cancer-related infections: Vaccines can protect against some infections associated with cancer, such as the HPV and hepatitis B. Lifestyle can also play an important role in preventing infection.
- Reducing exposure to environmental and occupational carcinogens: These include radon, asbestos and many industrial chemicals.