Ontario Lowers Colorectal Cancer Screening Age to 45

Ontario will lower the age for colorectal cancer screening to 45 from 50 due to a sustained rise in cases among younger adults, according to Cancer Care Ontario.

The lower recommended age for average-risk colorectal cancer screening will take effect July 1 as part of updates to the province’s Colon Cancer Check program, the provincial agency responsible for cancer screening guidance said on its website on May 5.

Advocacy group Colorectal Cancer Resource & Action Network (CCRAN) welcomed the decision in a social media post, saying that form of cancer is highly treatable in its early stages.

“This is exactly why CCRAN has been advocating for this change since 2020. Ontario joins Prince Edward Island as the second province to make screening at 45 a reality,” the organization said, adding that other provinces and territories should adopt similar measures.

On March 30, Prince Edward Island became the first province in Canada to formally lower its screening age to 45. The province described the move as an evidence-based public health decision aimed at improving early detection, reducing the need for invasive treatment, and in some cases preventing cancer entirely through the removal of precancerous growths.

Colorectal cancer remains the fourth most commonly diagnosed cancer in Canada and the second leading cause of cancer-related death, according to the Canadian Cancer Society. While traditionally considered a disease affecting older adults, cases among people under the age of 50 have risen steadily in recent decades, with studies showing younger cohorts now face a higher risk of diagnosis than previous generations at the same age.

At the same time, health-system planning documents suggest the policy change will take up more resources. According to a Canadian Partnership Against Cancer briefing on screening age expansion, lowering eligibility is expected to significantly increase demand for fecal immunochemical testing (FIT) as well as follow-up colonoscopies, requiring additional staffing, endoscopy capacity, and diagnostic resources.

The briefing states that while earlier screening is expected to improve long-term outcomes, it also places immediate pressure on already constrained gastrointestinal services. It says implementation will require careful planning to ensure diagnostic wait times do not lengthen as more patients enter the system.

The analysis also highlights that evidence on routine screening effectiveness in younger populations is still developing. While the rise in cases among people aged 45 to 49 is well documented, long-term data on the outcomes of large-scale screening at that age is limited. The briefing suggests that lowering the starting age may not fully address broader epidemiological trends, particularly as increasing incidence has also been observed in individuals under 45.