Colon cancer starts small enough to remove.
It is the third most common cancer in the world, with more than 1.9 million new cases a year. Here is where it stands, in eight readings.
It is showing up earlier.
In 1995, 11% of colorectal cancers in the United States were found in people under 55. By 2019 it was 20%. Nobody has fully explained why.
Most of it happens slowly.
A polyp typically needs about a decade of accumulated mutations to become cancer, and most polyps never do. That decade is the opening screening works in. About 3% of cases trace to Lynch syndrome, an inherited fault in DNA repair.
When it is found decides most of what follows.
alive five years on, found still in the colon
once it reaches nearby lymph nodes
once it has spread to distant organs
cases are caught at that first stage
The age to start screening.
In 2021 the US Preventive Services Task Force lowered the starting age for people at average risk from 50 to 45. A colonoscopy can remove polyps in the same visit, so screening prevents this cancer as well as finding it.
New cases a year by 2040.
In 2020 there were 1.9 million new cases and more than 930,000 deaths. The International Agency for Research on Cancer expects cases to rise 63% by 2040 as populations grow and age.
Tumours gone, in one trial.
Every patient who finished a course of the antibody dostarlimab for a rare, mismatch-repair-deficient form of rectal cancer had no detectable tumour left. It is not yet approved for that use. In 2024 the FDA approved the first blood test for screening; a positive result still needs a colonoscopy.
Most of this is preventable.
More than half of colorectal cancers are linked to risk factors that can change. Found early, nine in ten people are alive five years later.
If you are 45 or older, or it runs in your family, ask a doctor about screening.
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