TORONTO — Ground is being gained on many fronts in the war against cancer, but one of the deadliest — liver cancer — is still on the rise, the Canadian Cancer Society said Wednesday.
About half of liver cancer cases in Canada are probably preventable, the research and advocacy organization said as it released its annual estimates of the toll cancers will exact in Canada in 2013.
Overall, the society estimates 187,600 people will learn they have a new cancer this year (excluding non-melanoma skin cancers) and 75,500 Canadians will die from some form of the disease.
The big four remain breast cancer, prostate cancer, colorectal cancer and lung cancer, but rates of these diseases are either stable or declining, says Prithwish De, a cancer epidemiologist with the cancer society.
But the same is not true for liver cancer, which currently claims the lives of four out of five people diagnosed with it. Since 1970, the incidence of liver cancer has tripled in Canadian men and doubled in women.
Primary liver cancer — as opposed to cancer that spreads from another site to the liver — is still rare. The society estimates 2,000 people will be diagnosed with it in 2013 and 1,000 people will succumb to the disease. Worldwide, liver cancer is the third leading cause of cancer deaths, after lung and stomach cancer.
The cancer is so deadly because most cases are not found until the disease has progressed beyond the point of cure. When liver cancer is found early it generally responds well to treatment, says Dr. Sean Cleary, a liver surgical oncologist at Toronto’s University Health Network.
“One of the problems with this disease is that it does not develop symptoms or patients aren’t aware that they have the problem until the disease is very advanced, at a very large and untreatable stage,” he said.
Science has made little progress improving the survival chances of people with liver cancer. Over the past 20 years, the survival rate has risen by only between two and three per cent, De says.
But the toll the disease takes could be dramatically lowered if people at high risk of developing the liver cancer took some proactive steps, experts say.
Excess alcohol consumption, obesity and diabetes are known to be risk factors for developing liver cancer. Cutting back on alcohol and taking steps to maintain a healthy weight should lower one’s liver cancer risk, they suggest.
Another way to combat the disease is by addressing two related conditions that can be precursors to liver cancer — hepatitis B and C, which are viral infections of the liver. There is currently a vaccine against hepatitis B, but none for hepatitis C.
People who are at high risk of having one or the other infection should consider talking with their doctors about being tested for hepatitis. Treatment can often clear the infections, the experts say.
“Many individuals who are infected with either acute or chronic hepatitis infections may not be aware that they’re infected. And we’re trying to let Canadians know that there is a way to get tested and find out if you are infected by either hepatitis B or C,” says De.
Last year the U.S. Centers for Disease Control urged all baby boomers to have a one-time test for hepatitis C because of the liver cancer risk. The Canadian Liver Foundation later echoed that advice.
But the Public Health Agency of Canada is studying whether it makes sense to issue a similar recommendation in Canada, where the rate of hepatitis C is lower than in the U.S. While it deliberates, the cancer society is content to wait for evidence-based advice.
“Because we’re lacking that evidence in Canada it’s kind of premature to say whether (across-the-board) screening would be beneficial to that age group,” De says.
“And so, from the Canadian Cancer Society’s perspective, we’d like to wait until there’s a good solid base of evidence before we say anything about screening in specific age cohorts.”
Instead, they recommend a discussion about screening for people who had a blood transfusion before 1990, who use or used intravenous drugs or who moved to Canada from parts of the world where hepatitis B and C are common — Asia and sub-Saharan Africa for hepatitis B, Japan and southern Europe for hepatitis C, Cleary says.
Others at risk are people who’ve had high-risk sexual contacts and received tattoos in non-reputable tattoo parlours, he said.
“Individuals who have those risk factors are definitely candidates for speaking to their doctors about finding out whether testing for hepatitis B or C and whether any other types of counselling would be beneficial for them for reducing their risk of liver cancer,” De says.