More Canadians Living With, and Surviving, Cancer: Report

A health care worker audits different health units at a hospital in Toronto on Dec. 9, 2020. Nathan Denette/The Canadian Press

More than 1.5 million Canadians have been diagnosed with cancer in the last 25 years and were still alive in January 2018, according to a new report on cancer prevalence published by the Canadian Cancer Society (CCS).

Among the Canadians with cancer, there were almost 1.7 million cancer cases, as one person can receive more than one cancer diagnosis. Almost half of all cancer cases involved breast, prostate, or colorectal cancers. Other common diagnoses included skin cancer, thyroid cancer, bladder cancer, Hodgkin lymphoma, uterine cancer, and lung cancer.

Cancer prevalence is the number of people who are diagnosed with cancer and then go on to survive. The report said cancer outcomes have improved over the last several decades in general, even though the prevalence of cancer in Canada has increased from 10 years ago.

In other words, people with cancer are being diagnosed earlier and surviving longer. But, the trend is also a rising number of Canadians being diagnosed with cancer than in the past. In 2012, according to the report, approximately 193,000 people in Canada were diagnosed with cancer. By 2017, that number had risen to 206,000.

Cancer on the Rise

The CCS estimates that 233,900 people will be diagnosed with cancer in 2022. This growth in incidence is being attributed to Canada’s growing and aging population. Older Canadians are more likely to be diagnosed with cancer, according to the report.

As of Jan. 1, 2018, almost 18,000 children under the age of 15 had been diagnosed with cancer in the previous 25-year period studied. One in four had received a cancer diagnosis in the last five years, and 10 percent had been diagnosed within the previous two years.

Among childhood cancer diagnoses, leukemia was responsible for 35 percent of diagnosed cancers. The report said: “Most childhood cancer survivors have an increased lifetime risk of being diagnosed with a second primary malignancy. This higher risk can be due to genetic predispositions or certain adverse effects induced through treatment toxicity.”

The report was not all bad news, however. It noted that survival outcomes for children with cancer are expected to increase in the future, especially for cancers affecting the blood and bone marrow.

No COVID Data Considered

The report only used data for a 25-year time frame, up until Jan. 1, 2018. The data in the report does not account for any changes in diagnosis, cancer control, and prevalence due to COVID-19. However, the report notes that international data suggests there were 40 percent fewer cancer diagnoses made between March 9 and May 17, 2020, when compared with how many average cancer diagnoses were made in the same time frame in 2018 and 2019.

In addition, according to the CSS, there is some early data from provincial figures suggesting that cancer surgeries were reduced in number during the first four months of COVID-19.

A September 2022 report, “Living at the crossroads of COVID-19 and cancer,” said the pandemic created delays and interruptions in health care, which could result in more late-stage diagnoses. Finding the cancer later means a lower survival rate, according to the CSS.

Regionally, there are disparities as well. Cancer incidence per 100,000 people in the last 25 years was generally highest in eastern provinces and lower in western provinces. The prevalence of cancer was higher in rural Canada than in urban, with the report attributing the higher cancer numbers in rural areas to their typically older populations compared to the city.

The CCS report also noted that established cancer risk factors, such as smoking, alcohol consumption, and obesity, are more common risk factors in those living rurally, contributing to higher cancer incidence. In addition, travel from rural areas to larger centres for medical care may be more difficult for people living in the country.

Poor Chance of Surviving Lung Cancer

The report noted that the incidence rate of colorectal cancer is lower than lung cancer, but lung cancer has a relatively poor prognosis for survival. “For both breast and prostate cancers, about two-thirds of cases were five to 25 years since diagnosis, whereas 15 percent of each were still within the first two years since diagnosis. In contrast, for lung cancer only 37 percent were more than five years since their diagnosis.”

There are also differences in how cancer affects the sexes, defined by the report as “those assigned male and female at birth.”

Cancer of the bladder, kidney and renal pelvis, head and neck, stomach, liver, and esophagus are three times more prevalent in males. Thyroid cancers in females are three times more prevalent than in men.

The report says that “these observed sex differences in prevalence may be reflective of differences in genetic factors and risk factor distributions for these cancer types, as well as differences in diagnostic and referral patterns.”

Nearly half of all 25-year prevalent cancers among males were due to prostate and colorectal cancers. The age group most affected by the commonly diagnosed cancers was highest in the age group from 70 to 79 years. For females, breast cancer was highest in the 60-69 year age group.

“Breast cancer was the most common 25-year prevalent cancer in all geographic regions except Newfoundland and Labrador, New Brunswick, and Prince Edward Island, where prostate cancer was most common,” said the report.

Health Care Strain

Income also played a role in cancer statistics, but varied by type of cancer. The highest neighborhood incomes reported higher levels of breast and prostate cancers. Low-income Canadians had a higher prevalence of colorectal and lung cancers, and people in these lower-income groups were less likely to survive.

In the news release accompanying the study, Jennifer Gillis, CCS senior manager of surveillance, said, “Increasing prevalence—more people being diagnosed and more surviving—creates long-term strain on our healthcare system and underlines why we must work together to create a system that can evolve as patients’ needs evolve from diagnosis through survival or end of life care.”

Analyzing statistics related to the ongoing rise in new cancer cases diagnosed annually, as well as the number of people who survive beyond their cancer diagnoses, is intended to help governments adequately plan and prepare for ongoing health care resources required. For example, a recent study estimated cancer care costs went from $2.9 billion per year in 2005 to $7.5 billion by 2012. The CSS said that a simulation-based study estimated that the direct health care system cost of cancer in 2021 may have reached $22.8 billion.