It really is true: Colon cancer is rising in younger adults; it’s no longer an “old person’s disease.”
While rates are dropping in people over 50 — largely thanks to routine screening — doctors are now seeing a steady rise in younger patients, including people in their 30s.
A long-term study from Switzerland shows that cases in younger adults have been climbing for decades, and many of these patients are being diagnosed at later stages.
The study was carried out by teams at the University of Geneva and the Geneva University Hospitals.
It was published in the European Journal of Cancer and looked at nearly 100,000 colorectal cancer cases across Switzerland over a 40-year period.
In 2022 alone, there were more than 1.9 million new cases worldwide and close to 900,000 deaths, according to the World Health Organization.
Rising Cases in Younger Age Groups
Screening programs have helped bring down numbers in adults over 50, but the trend is moving in the opposite direction for younger people in many high income countries.
According to clinicians involved in the study, cases are now appearing in patients in their 30s with no family history or obvious risk factors.
These individuals are often diagnosed only after the disease has already spread.
This is because colon cancer isn’t the first thing that comes to a physician’s mind when a 35-year-old complains of stomach pain and constipation — issues that can be caused by numerous benign conditions.
40 Years of Swiss Cancer Data Analyzed
To better understand the trend, researchers examined 96,410 colorectal cancer cases recorded between 1980 and 2021.
The data came from national and regional cancer registries across Switzerland.
The results showed that cancers diagnosed before age 50 made up about 6.1% of all cases.
In younger adults, incidence increased by roughly 0.5% per year, reaching close to seven cases per 100,000 person-years.
At the same time, rates in the 50 to 74 age group declined significantly, likely due to screening programs.
Men in that group saw a 1.7% drop, while women saw a 2.8% decrease.
Different Cancer Patterns in Younger Patients
Researchers also noticed that the rise in younger patients wasn’t uniform across all types.
Rectal cancers increased in both men and women, while right-sided colon cancers were more common in younger women.
These differences may point to varying biological or environmental factors, according to the research team.
They also found that younger patients were more likely to be diagnosed at an advanced stage.
About 28% already had metastatic disease at diagnosis, compared to around 20% in older adults.
Symptoms and the Importance of Earlier Checks
Doctors involved in the study stress that symptom awareness could make a real difference.
Warning signs like persistent abdominal pain, blood in the stool, unexplained weight loss or ongoing changes in bowel habits shouldn’t be ignored, even in younger people.
In some countries, including the United States, screening guidelines have already been lowered to start at age 45.
For people with higher genetic risk, doctors may recommend screening even earlier.
Why Cases May Be Increasing
Researchers are still working to understand what’s driving this shift.
Possible explanations include modern diet changes, rising obesity rates, lifestyle factors, and early-life environmental exposures that may influence gut health.
However, there is still no single clear cause that explains the full trend.
The increase is likely due to a mix of factors that scientists continue to study.
Additional Symptoms
The following symptoms can mean colon cancer: stools that come out in the form of ribbons or are as narrow as a pencil; unexplained diarrhea or constipation (these two can also be alternating); back pain despite no known musculoskeletal cause; and unexplained fatigue.
Another suspicious symptom is that of feeling as though a bowel movement is still yet to come, despite having just had one. And none comes.
