Ontario to start screening for colorectal cancer at age 45 instead of 50

TORONTO — New guidelines published online by Cancer Care Ontario say the province is lowering its colorectal cancer screening age from 50 to 45 in response to a “notable” increase in younger people diagnosed with the disease.

An Ontario Health document outlining the new recommendation says the change starts on July 1.

Prince Edward Island was the first province in the country to lower its screening age in March.

Colorectal Cancer Canada and the Canadian Cancer Society have been calling on all provinces and territories to make this change, citing evidence that shows people under 50 are two-to-2.5 times more likely to be diagnosed with colorectal cancer than they were in previous generations.

The United States and Australia have also lowered their colorectal cancer screening ages to 45.

The Ontario government document that’s meant to inform primary care providers says the decision is based on expert panel guidance, evidence of an increase in early onset colorectal cancer in the province, and modelling showing earlier screening reduces the incidence and mortality of the disease.

Ontario’s Ministry of Health said in a statement the program changes will help detect and treat cancer earlier, building on the province’s move two years ago to lower the age of breast cancer screening from 50 to 40.

A routine colorectal screening is called a fecal immunochemical test — or FIT — and it involves swabbing stool at home and then dropping it off or sending it to a lab. It’s recommended that those with normal test results repeat the process after two years.

If the sample tests positive for blood in the stool, that person is referred for a colonoscopy to check for cancer.

The government says in the guidance that screening invitation letters will be sent out in a “phased manner,” but after the July start date doctors can order the FIT for anyone aged 45 to 49.

It’s also lowering the recommended age for colonoscopies for people who have an immediate relative who was under the age of 60 when they were diagnosed with colorectal cancer.

That group will start screening at 40 — rather than 50 — or 10 years earlier than the age their youngest relative was diagnosed, whichever comes first, with a screening interval of five years.

Those who only have one relative diagnosed with colorectal cancer at the age of 60 or older will now be screened with FIT every two years starting at 45, instead of a colonoscopy.

The government said that change is based on evidence, which shows that a person with one older relative diagnosed with colorectal cancer is at a similar risk of the disease to the general population. It’s also expected to shorten the wait for a colonoscopy for those who have abnormal results.

The government tells health providers to expect a “modest increase” in abnormal test results as more people get the test.

It also says there will be an increased demand for colorectal cancer surgeries and pathology specimens, but that “over time, these volumes are expected to stabilize as pre-cancers are detected and removed.”

“Ontario’s decision to lower the screening age to 45 is a huge step forward,” said Barry Stein, president and CEO of Colorectal Cancer Canada.

“It’s time for all other provinces and territories to follow suit.”

In Ontario, the drop-off locations for completed FIT kits are also changing, with the guidance noting patients can leave them at any Rexall location or send them to In-Common Laboratories by mail.

This report by The Canadian Press was first published May 5, 2026.

Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.

Hannah Alberga, The Canadian Press