NS oncologist explains connection between alcohol and cancer
Canada’s new alcohol guidelines, which warn of the risks between drinking and cancer, are welcomed by a leading Nova Scotia oncologist.
The report, released in January, delivered the message that having more than two drinks a week increases the risk of various types of cancer.
That the risk increases with each additional consumption of alcohol.
“It’s a carcinogen and something we should look out for,” said Dr. Bruce Colwell, a medical oncologist who is also responsible for systemic therapies at Nova Scotia’s cancer treatment program and an associate professor at Dalhousie University in Halifax.
While the links between alcohol and cancer have been known for decades, the recent report from the Canadian Center on Substance Use and Addiction makes it clear that there is no safe drinking level.
“We should look at something that causes cancer and try to avoid it as much as possible,” Colwell said.
The report identifies breast and colorectal cancers as the most commonly associated with alcohol consumption, followed by cancers of the rectum, mouth, pharynx, liver, esophagus and larynx.
There are a number of theories as to how this happens.
“There is a breakdown product of alcohol called acetaldehyde and it is a known carcinogen. It will damage the DNA and directly cause cells to become cancerous,” Colwell said.
Additionally, there is evidence that alcohol itself causes cancer through a process called oxidation, Colwell said. And alcohol can also increase estrogen levels, he said, which is a risk factor for breast cancer.
It is difficult to pinpoint the causes of cancer in his own patients, he acknowledged, although a number of other factors such as a person’s diet can also play a role.
Nor is he there to judge anyone when treating them.
“It’s really hard to say that alcohol is so prevalent why you got cancer, but we know from these big studies that people who drink less have less cancer,” he said.
Age remains the biggest risk factor for cancer because DNA naturally becomes damaged as people age, he notes.
Almost half of Canadians are unaware of the risks
According to the Canadian Cancer Society, reducing alcohol consumption is one of the most important ways people can reduce their risk of cancer.
The charity now wants to take action following the release of the report, including introducing health warnings on alcohol products.
“Over 40 percent of Canadians are unaware that drinking alcohol increases these risks, so this is a great opportunity for people to learn, have conversations and think,” said Ciana Van Dusen, Advocacy Manager of Prevention for the Canadian Cancer Society.
Statistics from 2015 linked more than 3,000 new cancer cases across the country to alcohol, Van Dusen said, with a forecast that the number could rise to over 10,000 by 2042.
Similar to previous studies linking smoking to cancer, Colwell expects it will take time for the new guidelines to have a big impact.
However, he sees it as a good thing that there is now clear information that people should take into account.
“There isn’t anyone who starts smoking today who doesn’t know the damage it’s doing,” he said. “When they start having more than two drinks a week, you have to start thinking. It’s a balance and hopefully they’ll think about it beforehand.”
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