Ontario Lowers Colorectal Cancer Screening Age to 45 as Cases Climb Among Younger Adults

Ontario will lower the eligibility age for its publicly funded colorectal cancer screening program to 45, the province announced this week, expanding access to the free at-home stool test that has been credited with catching tumours earlier and reducing deaths. The change brings Canada's largest provincial screening program into line with international guidance reflecting a sharp rise in colorectal cancer among adults under 50.

The expansion adds roughly two million additional Ontarians to the eligible population. Ontario Health, the agency that administers the ColonCancerCheck program, will begin inviting people aged 45 and over to receive the fecal immunochemical test, or FIT, through their family doctor or by self-referral.

What was announced

Under the existing program, Ontarians aged 50 to 74 at average risk of colorectal cancer have been encouraged to complete a FIT every two years. The test, which can be done at home, looks for hidden blood in the stool. Patients with a positive FIT are referred for follow-up colonoscopy through the publicly funded system.

The expansion lowers the starting age to 45 for average-risk individuals, while maintaining the existing colonoscopy pathway for people with a family history of colorectal cancer or other risk factors. Family physicians, nurse practitioners and pharmacists will be able to order or distribute test kits, with results returned to Ontario Health and to the patient.

The change will be phased in over the coming year, with rollout to family practices first and broader public outreach in the months to follow. The province estimates that, at full uptake, the expanded program will identify thousands of additional cancers and precancerous polyps each year that would otherwise have been caught at a later, more dangerous stage.

Why the change

Colorectal cancer incidence has been rising steadily among adults under 50 in Canada, the United States and several other high-income countries. Researchers have not fully explained the trend, although diet, sedentary lifestyles, antibiotic exposure, gut microbiome changes and other environmental factors are all under active study.

In 2021, the U.S. Preventive Services Task Force lowered its recommended screening age to 45, a change that has since been adopted by leading Canadian and international clinical bodies, including the Canadian Cancer Society. Several Canadian provinces have been weighing similar moves, with British Columbia, Quebec, Manitoba and Alberta all reviewing their programs.

Ontario's decision follows extensive consultation with provincial cancer experts. Cancer Care Ontario, now part of Ontario Health, modelled the impact of lowering the screening age and concluded that the expanded eligibility would deliver substantial benefits at a manageable cost, both clinically and operationally.

What patients will experience

For most eligible Ontarians, the screening change will be invisible until they receive an invitation by mail or a recommendation from their primary care provider. The FIT kit is mailed to the patient, returned by mail to the central laboratory and processed without the patient needing to visit a clinic or undergo a procedure.

Those with a positive FIT are referred for a follow-up colonoscopy, which remains the gold standard for confirming the presence of cancer or precancerous polyps. Ontario Health said it will work with hospitals to ensure follow-up capacity, although colonoscopy waits have been a chronic concern in some regions.

For people who do not have a family doctor, an issue affecting a significant share of Ontarians, the province said it will continue to expand alternative pathways, including community health centres, nurse practitioner-led clinics and pharmacist-distributed test kits.

System capacity concerns

Lowering the screening age will increase demand on colonoscopy services, which were already under strain after the pandemic-era backlog. The Ontario Medical Association welcomed the expansion in principle but said it will only deliver its full benefit if the province invests in additional gastroenterology and colorectal surgery capacity.

Hospitals across the province have been working to expand endoscopy throughput, including by extending operating hours, hiring more endoscopy nurses and using freestanding ambulatory clinics. The province said the screening expansion will be paired with additional funding for follow-up services, although precise figures were not released with the announcement.

Patient advocacy organisations including Colorectal Cancer Canada welcomed the change, noting that earlier detection saves lives and reduces the cost of treatment. The organisation called on other provinces to follow Ontario's lead.

Equity considerations

Colorectal cancer outcomes in Ontario and across Canada are not evenly distributed. Indigenous communities, Black Canadians and people living in rural and remote areas face additional barriers to screening, follow-up and treatment. Ontario Health said the expansion will be paired with targeted outreach in under-served communities, including culturally adapted messaging and partnerships with Indigenous health organisations.

The province has been investing in mobile screening services and community health navigators to reach populations less likely to engage with the regular screening program. Those investments will be expanded as part of the broader rollout, officials said.

Treatment advances and outcomes

Treatment options for colorectal cancer have advanced significantly over the past decade. Surgical techniques, including minimally invasive and robotic approaches, have reduced recovery times and improved outcomes for many patients. Chemotherapy regimens have become more targeted, with biomarker-driven selection allowing clinicians to match patients with the most effective treatments.

Immunotherapy has emerged as a powerful tool for certain subsets of colorectal cancer patients, particularly those with specific genetic markers. Clinical trials continue to test new combinations of treatments, with Canadian researchers actively engaged in international collaborations that advance the standard of care.

Survival rates for early-stage colorectal cancer remain high, particularly when the disease is detected before it has spread beyond the bowel wall. The five-year survival rate for stage one disease exceeds 90 per cent, dropping significantly when cancer reaches lymph nodes or distant organs.

Multidisciplinary care teams, including surgeons, medical oncologists, radiation oncologists, nurses, social workers and supportive care providers, work together to deliver coordinated treatment for colorectal cancer patients across Ontario. Cancer centres in major hospitals serve as hubs for complex treatment, with community oncology programs supporting patients closer to home for many aspects of care.

National implications

Ontario's move is likely to accelerate decisions in other provinces. British Columbia's screening program currently begins at 50, with active discussions underway about lowering the age. Quebec's screening program is more uneven, with FIT availability varying significantly between regions. Manitoba and Alberta have signalled openness to following Ontario's lead, although timelines remain unclear.

The federal government does not deliver provincial cancer screening programs but has a role in coordinating national approaches through the Canadian Partnership Against Cancer, which receives federal funding. The partnership has been promoting earlier screening for years and welcomed Ontario's announcement.

For Canadians who move between provinces, the patchwork of screening ages and processes can be confusing. National advocacy groups say a more consistent approach across provinces would improve outcomes and reduce administrative complexity.

Symptoms, risk factors and awareness

Colorectal cancer often develops slowly, sometimes over many years, with precancerous polyps preceding the development of invasive disease. Screening with the fecal immunochemical test or with colonoscopy can identify these polyps before they become cancerous, allowing for removal during a follow-up colonoscopy.

Symptoms of colorectal cancer can include changes in bowel habits, blood in the stool, unexplained weight loss, persistent abdominal pain or discomfort, and unexplained anemia. People experiencing any of these symptoms should consult a primary care provider, regardless of age or screening status.

Risk factors include family history of colorectal cancer or precancerous polyps, certain inherited conditions, inflammatory bowel disease, a history of polyps, smoking, heavy alcohol use, obesity, physical inactivity, a diet high in red and processed meats, and Type 2 diabetes. People with elevated risk may require earlier or more frequent screening, including colonoscopy rather than FIT.

Awareness of the importance of screening has grown significantly in recent years, supported by celebrity diagnoses, public health campaigns and the broader recognition that early-onset disease is rising. Patient advocacy organisations have played key roles in pushing for earlier screening and in supporting Canadians navigating diagnosis and treatment.

The role of primary care

Primary care providers, including family physicians and nurse practitioners, play a central role in screening uptake. They are typically the first point of contact for patients with questions about screening and the entry point for referrals to follow-up colonoscopy when results require it.

The shortage of family physicians in many parts of Ontario complicates uptake of screening programs, including ColonCancerCheck. Patients without a regular primary care provider face higher barriers to engaging with screening and follow-up care, an equity issue that successive provincial governments have struggled to address.

The province has invested in expanded primary care models, including team-based care, community health centres and nurse practitioner-led clinics, as part of broader efforts to improve access. The integration of pharmacists into more aspects of primary care, including some screening-adjacent services, has been another element of the response to access challenges.

What's next

Ontario Health said it will begin sending invitations to newly eligible residents over the coming months, prioritising those most likely to benefit. The province has not set a specific date by which all eligible 45- to 49-year-olds will have received an invitation, but officials said full rollout is expected within the year.

For Ontarians who are 45 or older and curious about the program, the simplest next step is to speak with a primary care provider or to visit the ColonCancerCheck website for information on how to obtain a FIT kit. People with a family history of colorectal cancer or persistent symptoms should consult their physician about whether colonoscopy is more appropriate than FIT.

Colorectal cancer is among the most treatable cancers when caught early. The five-year survival rate for early-stage disease exceeds 90 per cent, falling sharply once the cancer has spread. Ontario's decision to lower the screening age is a bet that earlier detection in a younger, larger group of adults will translate over time into fewer late-stage diagnoses, less aggressive treatment and lives saved.