When colorectal cancer affects young people
For a long time, colorectal cancer was considered a disease of older people. However, current data shows that more and more people under the age of 50 are developing colorectal cancer. At the same time, the number of cases among people over 50 is declining.
Has colorectal cancer become more common overall?
No – the total number of new cases has remained relatively stable in recent years, but cases among people over 50 are declining. Among people under 50, they are rising significantly. This trend has been observed in the cancer registry of the canton of Zurich and in international registry studies, among other places.
Several factors may be contributing to the decline in the number of new diagnoses among people under 50:
- Introduction of colorectal cancer screening (colonoscopy)
- Removal of polyps as a precursor to cancer
- Decline in certain risk factors such as alcohol consumption and smoking
- More conscious nutrition and increased physical activity
Why are new diagnoses of colorectal cancer increasing among people under 50?
That is the crucial question, and one that has not yet been fully answered. Many of the young patients affected are athletic, eat healthily, do not smoke, and drink little alcohol. Classic risk factors therefore do not sufficiently explain the increase.
International studies show:
- The increase affects the entire colon and rectum.
- Left-sided tumors are particularly common in women.
- Men are more frequently affected by right-sided and rectal tumors.
Welche möglichen Ursachen werden diskutiert?
Experts such as Prof. Frank Frizelle (New Zealand) discuss several hypotheses:
Changes in the gut microbiome
Certain bacteria—such as toxin-producing Bacteroides fragilis—are suspected of promoting inflammation and DNA damage.
Environmental factors
Among other things, the following will be discussed:
- Microplastics
- Processed foods
- Early exposure to antibiotics
- Chronic inflammatory processes
Changed exposure in early life
Influencing factors in childhood and adolescence could play a greater role than previously assumed.
Even if you are under 50, you should seek medical advice if you have blood in your stool, persistent abdominal pain, unexplained weight loss, changes in bowel habits, etc. Colon cancer is treatable—especially if it is detected early.
Quellen
- Barot S et al. Swedish National Cancer Registry Study 1993–2019 (Early-Onset Colorectal Cancer)
- Rohrmann S et al. Cancer Registry Zurich; Wanner M et al. SMW 2020; Cancer Med 2023
- New Zealand epidemiological data, Frizelle F., Tumorboard-Fortbildung 10.2.26
- Blaser MJ, Kirschner D. The equilibria that allow bacterial persistence in human hosts. Nature. 2007