A quarter of a century of cancer data is now available in a jointly published report by the Canadian Cancer Society, Statistics Canada and the Public Health Agency of Canada on Tuesday.
Canadian Cancer Statistics 2022 special report on cancer prevalence sheds light on the most common forms of cancer during the 25 years between 1994 and 2018, as well as the populations most likely to be diagnosed.
As the number of people living with or after cancer in Canada increases, so will the demand for cancer care and support.
The report is intended to help identify gaps in health care and cancer care, and offer some clues as to how resources can be allocated to fill those gaps, according to Jeff Latimer, director general of health statistics at Statistics Canada.
“Timely and accurate data on cancer prevalence in Canada is critical to understanding the cost of the disease to society and our health care system,” Latimer said in a Press release issued on Tuesday.
“The data is invaluable in evaluating cancer outcomes, measuring how far we’ve come and identifying areas for improvement.”
CTVNews.ca explores some key findings from the report below.
All of the following rates are per 100,000 people, over a 25-year period, unless otherwise noted. The report did not include data from Quebec.
PREVALENCE BY TYPE
According to the report, cancer of the reproductive organs and colorectal cancer are the most prevalent cancers in all of Canada, by a wide margin.
From 1994 to 2018, breast cancer accounted for 19.4% of all diagnoses, while prostate cancer accounted for 17.8% and colorectal cancer 11.3%.
Melanoma accounted for 5.5% of diagnoses, thyroid cancer 5%, bladder cancer 4.6%, non-Hodgkin’s lymphoma 4.5%, uterine cancer 4.4%, lung and bronchial cancers for 4.1%, kidney cancer and renal pelvis cancer for 3.2 percent, and all other cancers for 20.2 percent.
PREVALENCE BY DURATION
According to the study, the majority of people, 60.9 percent, who had cancer or were living after cancer were between five and 25 years after their diagnosis. This duration represented the majority of people who had been diagnosed with breast, prostate and colorectal cancer.
Another 20.7 percent were between two and five years old, and 18.4 percent were between zero and two years old.
Among people with lung and bronchial cancer, 37.5 percent were between zero and two years from diagnosis, 37.1 percent were between five and 25 years old, and 25.4 percent were between two and five years old. years.
According to the report, the first two years after diagnosis are when patients are most likely to receive primary cancer treatment or recover from its effects.
“The third to fifth year after diagnosis is a period that generally requires close clinical follow-up for recurrence or another primary cancer, as well as supportive care,” the report states.
“People who live more than five years after a cancer diagnosis have probably completed their treatment, but some may still need clinical follow-up and supportive care.”
During study periods of two and five years, all cancers were generally more common in rural settings compared to urban settings.
This was the case in all provinces and territories except Nunavut, where the entire population was considered rural, and Manitoba, where the prevalence was about the same.
One factor driving this urban-rural divide is likely to be age, the report states, as Canadians living in rural areas tend to be older than those in urban areas and cancer diagnosis rates are higher in people greater.
The report said that established cancer risk factors “such as smoking, alcohol use and obesity” are also more common among people living in rural areas, compared to those living in urban areas.
PREVALENCE BY PROVINCE
Between 1994 and 2018, cancer rates were highest in the eastern provinces and Ontario, and generally lowest in the central and western provinces.
Specifically, cancer prevalence was highest in Newfoundland and Labrador, followed by New Brunswick, Nova Scotia, PEI, Ontario, British Columbia, Manitoba, Saskatchewan, Alberta, Yukon, Northwest Territories, and Nunavut, in that order. Québec was not included.
As with the rates in urban and rural settings, the authors said that differences in age distribution, risk factors and diagnoses influence the rates in each province.
PREVALENCE OVER TIME
The study found that national cancer rates per 100,000 people increased gradually over 25 years, from 1994 to 2018. However, the authors attribute the increase to an aging population, as well as better cancer screening tests and treatments, that increase the chances of survival in certain types of cancer
The report did not look at environmental factors that could contribute to cancer rates and outcomes, such as exposure to known carcinogens, and said the national data needed to better understand those factors in Canada is “limited or nonexistent.”
“Together, the cancer control community is working to address these important data and knowledge gaps so that we can better identify disparities in outcomes that require further attention and investment,” the report concludes.