Ontario colorectal cancer screening age drops to 45 as diagnoses rise in younger adults

Ontario is lowering its colorectal cancer screening age from 50 to 45, making it the second province to do so after Prince Edward Island.

As of July 1, Ontarians aged 45 to 74 considered at average risk can access a free at-home screening test called a fecal immunochemical test (FIT), which detects hidden blood in the stool. People with abnormal results are referred for a colonoscopy.

The shift responds to a troubling trend: doctors across the world are seeing colorectal cancer diagnoses increase in younger people. Dr. Rebecca Auer, a colorectal cancer surgeon at The Ottawa Hospital, said the evidence became impossible to ignore. "We're seeing earlier colon cancer now than we were in the past," Auer said. "Particularly in the 45-to-50 age demographic, it's essentially as common as it is in people between 50 and 55."

Researchers are still investigating why younger adults face higher rates. Auer pointed to early-life exposure to ultra-processed diets, less fibre intake, and changes in the microbiome. She also cautioned against assuming the disease only affects people with obvious risk factors. "I see patients as young as in their early 20s with colon cancer," Auer said.

Michael Groves, a then-49-year-old who discovered a five-centimetre tumour during a colonoscopy in early 2021, believes earlier screening could have caught his Stage 3B cancer sooner. "If I had been screened at 45, my tumour would almost certainly have been found earlier," Groves said.