We don't want to wait until people have symptoms before we look
A disease once associated with the later chapters of life is now appearing in Canadians barely past the threshold of adulthood, and a London gastroenterologist is watching the pattern accelerate. Colorectal cancer — Canada's third most common cancer and its second-deadliest — now claims one in five of its new victims from people under 55, a generational shift physicians attribute to the accumulated weight of modern dietary and lifestyle habits. The cruel arithmetic of the disease is this: caught early, nine in ten people survive; caught late, nearly all do not. The most urgent medical advice, then, is also the most counterintuitive — seek investigation precisely when you feel no need to.
- Colorectal cancer is killing roughly 9,500 Canadians every year, and the cases arriving in younger patients are rising at a rate researchers describe as alarming.
- The survival gap between early and late detection is not incremental — it is the difference between a 90% five-year survival rate and a 10–12% one, making timing nearly everything.
- Physicians are pushing against a deeply ingrained human instinct: most people wait for symptoms before seeking help, but by the time symptoms appear, the disease has often advanced beyond easy reach.
- Decades of rising fast food consumption, ultra-processed diets, obesity, and sedentary living appear to have quietly lowered the age at which the disease takes hold.
- Screening programs exist and are underused — the medical community is now calling on younger adults to engage with them before their bodies give any warning at all.
Michael Sey, a gastroenterologist at London Health Sciences Centre, has been watching a troubling shift unfold. Colorectal cancer — long understood as a disease of older age — is now arriving in patients in their 20s, 30s, and 40s, and the pace is quickening.
The disease is already one of Canada's heaviest burdens: roughly 25,000 diagnoses each year, and nearly 9,500 deaths — the second-highest cancer mortality rate in the country. What makes those numbers both devastating and hopeful is the role that timing plays. Detected early, before symptoms surface, about 90 percent of patients survive five years past diagnosis. Detected late, that figure falls to between 10 and 12 percent. The margin between those two outcomes is not a matter of comfort or convenience. It is survival itself.
Sey's message to patients and fellow physicians is deliberately counterintuitive: go looking for colon cancer in people who have no reason to think they have it. Most people wait for blood in the stool, abdominal pain, or changes in bowel habits before seeking help — and by then, the disease has often progressed. He wants to change that instinct.
What sharpens the urgency is the generational dimension. While colorectal cancer rates have declined modestly overall, cases among people under 50 are climbing. One in five new diagnoses now occurs in someone under 55. In the United States, the Cancer Research Institute has identified colorectal cancer as the leading cause of cancer-related death among young people.
Sey traces the shift to lifestyle changes that began accelerating in the mid-twentieth century — the rise of fast food, ultra-processed diets, obesity, heavy alcohol use, and the relentless pace of modern life. Age remains the dominant risk factor, but the disease is multifactorial, and the cumulative effect of these habits appears to have pulled the risk profile toward younger generations.
The path forward is both personal and systemic. Younger adults should not assume distance from the disease. Screening exists and should be used proactively. Symptoms warrant attention — but the real opportunity lies in acting before symptoms appear, when the disease is still answerable to treatment and survival is measured in decades.
Michael Sey, a gastroenterologist at London Health Sciences Centre, sits in his office thinking about a troubling pattern he has watched unfold over recent years. Colorectal cancer, once reliably a disease of older age, has begun appearing in people in their 20s, 30s, and 40s. The cases keep coming. And they are coming faster.
Colorectal cancer remains one of Canada's most common cancers. About 25,000 people receive a diagnosis each year. Yet the disease carries a weight that its prevalence alone does not capture: it has the second-highest mortality rate of any cancer in the country, killing roughly 9,500 Canadians annually. The numbers are stark, but they contain a hidden mercy. If caught early, before symptoms announce themselves, about 90 percent of people survive five years past diagnosis. That survival rate collapses to between 10 and 12 percent once the cancer has advanced. The difference between early and late detection is not a matter of months or improved quality of life. It is the difference between living and dying.
This is why Sey and other physicians have begun pushing a counterintuitive message: get screened even when you feel fine. Most people, he explains, wait for symptoms to appear before they seek help. They notice blood in the stool, or abdominal pain, or a change in their bowel habits, and then they act. By then, the disease has often progressed. Sey wants to change that calculus. He wants doctors to "go looking for colon cancer" in people who have no reason to suspect they have it. The mindset shift required is significant. People do not naturally seek medical investigation when they feel well.
What makes the current moment urgent is the rise in diagnoses among younger people. Colorectal cancer cases overall have declined slightly in Canada and internationally, a success story built on screening and prevention. But that trend has not extended to people under 50. Cases in this age group are climbing at what researchers describe as an alarming rate. One in five new diagnoses now occurs in people under 55. The Cancer Research Institute, a U.S.-based nonprofit, has documented that colorectal cancer has become the leading cause of cancer-related death in young people.
Sey attributes this generational shift to changes in how we live and eat. He points to a transformation that began in the 1950s and 1960s and has accelerated since. Fast food consumption has risen. Obesity rates have climbed. Ultra-processed foods have become dietary staples. Smoking and heavy alcohol use remain risk factors. High-fat diets and red meat consumption play a role. Age remains the single most important risk factor for colorectal cancer, but Sey emphasizes that the disease is usually multifactorial—several conditions and behaviors combine to create risk. Still, he notes, the lifestyle changes of recent decades seem to have shifted the disease's age profile downward. "Our modern kind of busy, hectic lifestyle is maybe the factor that's causing this generational shift," he said. Most people diagnosed with colorectal cancer are still older, but the concerning reality is that younger people now face elevated risk as well.
The path forward requires both individual action and systemic change. People under 50 should not assume they are safe. Screening programs exist and should be used. Symptoms like rectal bleeding, blood in the stool, abdominal pain, changes in bowel habits, and unexplained weight loss warrant investigation—though Sey cautions that these signs do not automatically indicate colorectal cancer. The real power lies in screening before symptoms appear, in catching the disease when it is still treatable, when survival is measured in decades rather than months. For a disease that kills thousands of Canadians each year, the stakes of early detection could not be higher.
Notable Quotes
We don't want to wait until people have symptoms, when they're feeling unwell, before we go looking at it.— Michael Sey, gastroenterologist at London Health Sciences Centre
Our modern kind of busy, hectic lifestyle is maybe the factor that's causing this generational shift in the risk of colon cancer in people who are younger.— Michael Sey
The Hearth Conversation Another angle on the story
Why is colorectal cancer suddenly appearing in people so much younger than it used to?
It's not sudden in the sense of a new virus or infection. Sey sees it as a generational effect—the people in their 30s and 40s now grew up in a different food and lifestyle environment than their parents did. Fast food, processed foods, sedentary work, higher obesity rates. These things have been building for decades.
But colorectal cancer rates overall are going down in Canada. How can that be true if young people are getting it more?
The overall decline is real, and it's because older people are getting screened more effectively. The screening programs work. But younger people weren't being screened as aggressively, so the disease was catching them without warning. Now we're seeing those cases emerge.
The survival difference between early and late detection is enormous—90 percent versus 10 percent. That's almost binary.
Yes. It's not like some diseases where early detection buys you a few extra months. With colorectal cancer, early detection often means you live. Late detection often means you don't. That's why Sey is so insistent about screening people who feel perfectly fine.
What would make a 35-year-old actually go get screened if they feel healthy?
That's the cultural shift Sey is trying to create. Right now, people don't go to the doctor unless something hurts. But colorectal cancer doesn't hurt in the early stages. You feel fine. The only way to find it is to look for it deliberately, before symptoms announce the problem.
Is there anything people can actually do to reduce their risk?
Diet and lifestyle matter, though Sey is careful not to oversimplify. Less processed food, less red meat, maintaining a healthy weight, not smoking, moderate alcohol. But he also notes that age is still the most important factor. You can do everything right and still get colorectal cancer. That's why screening is so critical.