Screening has helped older people avoid colorectal cancer, but doctors are now seeing more cases in younger adults. In Switzerland, a 40‑year study shows the disease is appearing more often in people under 50, even in their thirties.
Researchers from the University of Geneva and Geneva University Hospitals examined almost 100,000 cancer records from 1980 to 2021. They found that cancers diagnosed before age 50 made up 6.1% of all cases, and the rate for this group grew by about 0.5% each year.
Colorectal Cancer at a Glance
Colorectal cancer is the third most common cancer worldwide and the second biggest cause of cancer death. In 2022, the World Health Organization reported over 1.9 million new cases and nearly 900,000 deaths.
Europe, Australia, and New Zealand have the highest diagnosis rates, while Eastern Europe sees the most deaths. In Switzerland, roughly 4,500 new cases are reported each year.
What the Swiss Data Revealed
The study showed a clear opposite trend for older adults (50‑74 years). In that group, cancer rates fell by 1.7% in men and 2.8% in women, thanks to regular screening.
For younger adults, the rise was driven mainly by rectal cancers in both sexes and right‑side colon cancers in young women. This suggests different biological or environmental factors may be at work.
More than a quarter (28%) of patients under 50 already had cancer spread to other parts of the body when diagnosed, compared with about 20% of older patients.
Spotting the Warning Signs
Knowing the symptoms can lead to earlier detection. Watch for persistent belly pain, blood in the stool, unexplained weight loss, or long‑lasting changes in bowel habits. Young people often think they are too young for cancer, but these signs should never be ignored.
Some countries, such as the United States, now start routine screening at age 45. People with a family history or hereditary risk should begin even earlier.
Possible Reasons for the Rise
Scientists are still exploring why colorectal cancer is climbing in younger people. Potential contributors include poorer diets, higher obesity rates, and early‑life exposure to chemicals that affect gut bacteria. No single cause has been proven yet.