- Incidence (new cases) and mortality rates (deaths) for colorectal cancer are expected to increase in the future among people in Ontario.
- Although incidence and mortality rates are expected to stabilize or go down over the next 10 years, they will begin a steady increase from 2030 onward.
- The overall increase in colorectal cancer incidence rates in the future will be driven by people in Ontario ages 40 to 79.
Despite decreasing in recent decades, the incidence and mortality rates for colorectal cancer are projected to go up in the future among people in Ontario. Although the recent trend of generally decreasing rates is expected to continue over the next 10 years, from 2030 onward the trend is projected to reverse.
In an analysis that will be published for the first time in the upcoming Ontario Cancer Statistics 2020 report by Ontario Health (Cancer Care Ontario), projected estimates of the future burden of cancer in Ontario suggest that the age-standardized incidence rate of colorectal cancer for men will decrease from 64.1 per 100,000 in 2020 to 60.7 in 2030, but will then increase to 63.9 per 100,000 by 2040. The rate is expected to decrease in women from 45.9 in 2020 to 44.3 in 2030, and then increase to 46.6 per 100,000 by 2040.
Similar but smaller changes are predicted for mortality, with rates among men decreasing from 21.8 per 100,000 in 2020 to 19.6 in 2030, and then climbing to 22.3 per 100,000 by 2040. Death rates among women will decrease from 15.4 to 14.0 before increasing to 14.3 per 100,000 over the same time period.
The projected trends in incidence rates in Ontario are similar to those expected for colorectal cancer in Canada and the U.S. over the next 20 years. In terms of mortality, a study that looked at separate colon and rectal mortality trends showed expected increases in rectal cancer death rates, but not colon cancer death rates, for Canada in the next 15 years.
These future estimates of colorectal cancer incidence can provide the information necessary for health services planning, redistribution of current health resources, policy considerations and development of infrastructure for better cancer control. However, long-term cancer incidence and mortality projections inherently carry some uncertainty and therefore need to be interpreted with caution. The reliability of projections depends on several factors, including the accuracy of the population forecasts, changes in the future prevalence of cancer risk factors and other factors that can quickly change cancer incidence or mortality rates, such as the introduction of a new method for early cancer detection or a new treatment.
People ages 40 to 79 will drive changes in rates
People in Ontario ages 40 to 79 will drive the increasing colorectal cancer incidence rate in the future. The age-specific incidence rate in people ages 40 to 59 is projected to increase 19.0% (from 44.1 new cases per 100,000 people in 2020 to 52.4 in 2040). The age-specific rate in people ages 60 to 79 is expected to increase by 6.0% (from 169.7 per 100,000 in 2020 to 179.8 in 2040). In contrast, the incidence among people in the youngest (ages 0 to 39) and oldest (80 or older) age groups are expected to decrease over the same period.
These age-specific trends suggest that the current cohort of people under age 40 will largely be responsible for the higher colorectal cancer rates in 20 years. In fact, cohorts under age 50 in other high-income jurisdictions have been reported to be at higher risk of colorectal cancer than older generations. The higher risk may be due to an increasing prevalence of risk factors such obesity and unhealthy diets in younger generations as well as a decrease in protective factors such as physical activity and sufficient intake of dietary fibre, and vegetables and fruit. In addition to higher risk of some cohorts, population growth and the aging of the population are likely to add to the anticipated future increase in colorectal cancer.
The age-specific mortality rate is also projected to increase among 40- to 79-year-olds, from 9.4 per 100,000 among those ages 40 to 59 in 2020 to 14.5 in 2040, and from 49.2 to 53.4 among those ages 60 to 79 over the same period.
Current burden of colorectal cancer
Colorectal cancer accounted for approximately 11% of all newly diagnosed cancer cases in Ontario, making it the third most common cancer after breast and lung cancer. It also represented 11% of all cancer deaths, and is the second leading cause of cancer death after lung cancer. Approximately 1 in 15 people in Ontario is expected to develop colorectal cancer in their lifetime.
Opportunities for changing the future burden of colorectal cancer
Colorectal cancer screening can help decrease the future burden of the disease because it increases the chance of finding cancer early when it is easier to treat. Colorectal cancer screening is testing done on people who may be at risk of getting colorectal cancer, but who have no symptoms and generally feel fine.
In Ontario, organized colorectal cancer screening services are delivered by the ColonCancerCheck (CCC) program. The CCC program screens 2 different groups of people who qualify for screening: those at average risk and those at increased risk.
Someone is at average risk if they are 50 to 74 years old with no first-degree relative (parent, brother, sister or child) who has been diagnosed with colorectal cancer. The CCC program recommends that people who have no symptoms and are at average risk get screened with the fecal immunochemical test (FIT) every 2 years.
Someone is at increased risk if they have a family history of colorectal cancer that includes 1 or more first-degree relatives with the disease. The CCC program recommends that people who have no symptoms and are at increased risk get screened with a colonoscopy. Someone at increased risk should start screening at age 50, or 10 years earlier than the age their first-degree relative was diagnosed with colorectal cancer, whichever comes first.
The CCC program does not recommend regular screening for people younger than age 50 with no first-degree relatives who have been diagnosed with colorectal cancer. Even though the number of colorectal cancers being diagnosed in younger adults is increasing in Canada, it is still relatively rare in adults younger than age 50.
In addition to screening with FIT, people can help reduce their risk of getting colorectal cancer by quitting smoking, limiting alcohol consumption, maintaining a healthy body weight, being physically active, eating a diet high in fibre (including vegetables, fruit and whole grains), and limiting intake of red and processed meat.
More research on why colorectal cancer incidence is increasing in young people should be encouraged.
To learn more about getting screened for colorectal cancer, please visit Screening for Colorectal Cancer.
To learn more about the projections and current burden of other cancers in Ontario, please contact firstname.lastname@example.org.