Cancer is the leading cause of death in Canada, where about two in five people are expected to be diagnosed with some form of the disease in their lifetime, and one in four are expected to die from it, according to the Canadian Cancer Statistics 2021 report.
Data from Statistics Canada show that cancer-related deaths accounted for 28.2 per cent of all deaths in 2019, followed by heart disease (18.5 per cent) and cerebrovascular diseases and accidents (4.8 per cent each).
But the new report on national cancer statistics, released Wednesday, also signals reasons for optimism. The overall death rate from cancer, for example, is down 37 per cent among men and 22 per cent among women since its peak in 1988. The five-year survival rate for all cancers has also increased from 55 per cent in the early 1990s to an estimated 65 per cent this year.
For prostate cancer, the death rate has dropped by half since its peak in 1995, from 45.1 per 100,000 men to an estimated 22.7 per 100,000 this year. The rate of thyroid cancer among both men and women is seeing an annual decrease of about 4.7 per cent, after many years of steep increases.
The Canadian Cancer Statistics Advisory Committee produced the report in partnership with the Canadian Cancer Society, Statistics Canada and the Public Health Agency of Canada.
Using historical incidence and survival data, along with mortality data up to 2018, the report both identifies cancer trends over the years and includes projections on the impact of the disease up to 2021.
While there are more than 100 types of cancer, four – lung, breast, colorectal and prostate – are expected to account for an estimated 46 per cent of all new cases this year.
Lung cancer
Lung cancer is the leading cause of cancer death in Canada, killing more people than colorectal, breast and prostate cancers combined. It is expected to be the most commonly diagnosed cancer this year, with a projected 29,600 new cases. Almost all of these cases (98 per cent) are expected to occur in people 50 or older.
According to the report, the incidence rate for lung cancer among men began decreasing in 1990, falling more steeply beginning in 2013. Meanwhile, the incidence rate among women increased significantly between 1984 and 1993, continuing to climb slowly until 2013, when it began to fall. This contrast is attributed to differences in cigarette smoking, which is the main risk factor for lung cancer.
The five-year lung cancer survival rate is 22 per cent, up from 13 in the early 1990s, owing in large part to advances in treatment, such as the increasing use of targeted therapy drugs.
Breast cancer
Breast cancer is the most commonly diagnosed cancer among women and is expected to be the second-most diagnosed cancer overall in Canada this year, with an estimated 28,000 new cases.
One in eight women are expected to be diagnosed with breast cancer in their lifetime, and one in 34 are expected to die from it. Still, this rate has fallen 46 per cent among women from its peak in 1986, from 42.7 deaths per 100,000 people to a projected rate of 21.1 deaths per 100,000 this year. This has been attributed to increased mammography screening and more effective therapies after diagnosis, the report said.
The five-year survival rate for breast cancer is 89 per cent, up from 82 per cent in the early 1990s.
Colorectal cancer
Colorectal cancer is expected to be the third-most commonly diagnosed cancer, and the second leading cause of cancer-related death, this year. About 24,800 Canadians are projected to be diagnosed with it and about 9,600 will die from it.
The majority of colorectal cancers are in people over 50. The report estimates that 56 per cent of new cases this year will be among people between the ages of 50 and 74, and 8 per cent among people under 50.
Death rates from this type of cancer are decreasing for both men and women, likely because of increased and improved screening, which can identify treatable precancerous polyps.
The five-year survival rate for colorectal cancer is 67 per cent, according to the report.
Prostate cancer
The prostate cancer death rate in Canada has fallen by 50 per cent since its peak in 1995. Still, it is expected to represent about one-fifth (24,000) of all new cancer cases among men this year, and about 4,500 men will die from it. About one in eight men will be diagnosed with prostate cancer in their lifetime.
This type of cancer is one of the least preventable, but the rate of survival is nearly 100 per cent if detected before it has spread. More than 90 per cent of men diagnosed with prostate cancer will survive more than five years.
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Andrea Woo