The Canadian Cancer Society (CCS) has called for a decrease in the age of colorectal cancer screening from the current 50 years to 45 years. The appeal follows accumulating evidence that younger Canadians are being diagnosed with colorectal cancer in greater numbers. 

“We are seeing that individuals who are in that 45- to 50-year-old age bracket are two to two and a half times more likely to be diagnosed [with colorectal cancer] than previous generations,” Brandon Purcell, advocacy manager of prevention and early detection at the CCS, told Medscape News Canada.

Canada is not unique in seeing a rise in colorectal cancer cases among its younger citizens. Some countries have responded by including individuals aged 45 years or older in organized colorectal cancer screening, he added.

“The US is one of the countries. Australia has done so, Japan has done so, and Taiwan has done so,” said Purcell. “We certainly wouldn’t be the first.”

The CCS calls for the fecal immunochemical test (FIT) to be performed every 2 years in average-risk individuals aged 45-50 years. It is urging provinces to ensure that patients who lack a primary care provider do not fall through the cracks when it comes to colorectal cancer screening.

“We want to make sure that individuals are able to self-refer [for the FIT],” said Purcell. “In this way, you can still take part in the [screening] program if you don’t have a family doctor.”

Provinces Run Screening Programs

Decreasing the colorectal cancer screening age to 45 years would affect healthcare resources, Purcell acknowledged. The provinces, which are responsible for running cancer screening programs in Canada, would not be expected to implement the recommendation in their screening programs immediately.

“If provinces want to take a gradual approach to reducing the age so that the systems have time to absorb the new intake of patients going into screening programs, such as accepting all the new FIT results at laboratories and making sure that there is capacity for any potential change in the number of colonoscopies that need to be conducted, we would certainly support them,” said Purcell.

Modelling Simulation Shows Impacts

Data published in The Journal of the Canadian Association of Gastroenterology suggest the positive effect that screening younger Canadians would have, given that the absolute colorectal cancer incidence rates in Canada among individuals younger than 50 years have been increasing.

Using data from the Canadian Cancer Registry, researchers created a model to simulate biennial FITs starting at age 45 or 50 years up to age 74 years between 2025 and 2071. They used four birth cohorts (1975-1979, 1980-1984,1985-1989, and 1990-1994). Based on data from the Canadian Community Health Survey, the researchers modelled screening participation as 43% and adherence with subsequent screening as 80%. The model assumed an 85% rate of compliance with undergoing colonoscopy after a positive FIT result.

The results suggested that the implementation of colorectal cancer screening at age 45 years would lead to 15,070 fewer cases and 6100 fewer deaths in Canada between 2025 and 2071. For every additional 100 colonoscopies, 3.5 fewer cases and 1.4 fewer deaths would be anticipated.

“These [birth cohorts] would be groups of people that would enter and exit screening eligibility over the next 45 years,” study author Darren Brenner, PhD, cancer epidemiologist and professor of oncology and community health sciences at the University of Calgary’s Cumming School of Medicine, Calgary, told Medscape News Canada.

Effects of Earlier Detection

If colorectal cancer is found at a younger age, it is less likely to need more advanced care, explained Brenner. “They’re going to be caught as polyps that would never develop into cancer at all,” he said. 

Indeed, the modelling that Brenner and his coauthors conducted suggested that decreasing the age at which colorectal cancer screening begins to 45 years may result in an overall cost savings of $233 million over the lifespan of eligible cohorts in their study. 

“It’s very expensive to treat advanced cancers,” said Brenner. “When you compare the increase in costs for more screening, it is cost-effective because the increase is offset by the reductions in a large number of cases that are prevented, and therefore a large number of avoided cancer treatments.”

Because a 45-year-old is not currently eligible for colorectal screening in Canada, he or she would receive a diagnosis after showing symptoms of colorectal cancer during a physician or emergency room visit, noted Brenner. “That leads to younger people being diagnosed with advanced cancers,” he said.

Purcell and Brenner had no relevant financial relationships.