# Colorectal cancer is rising again after 20 years, and scientists don't know why

Source: [Health & Medicine News -- ScienceDaily](https://www.sciencedaily.com/releases/2026/11/261111005843.htm) · 2026-11-12 · Medicine
Page: https://themorning.science/story/colorectal-cancer-is-rising-again-after-20-years-and-scientists-don-t-know-why-2643794b7e247c04
Kind: research · Impact: medium

## In brief

- A major new study reports colorectal cancer rates in the US are rising again after more than 20 years of decline.
- The increase is no longer limited to younger adults and appears across nearly every age group under 70, including some older Americans.
- The source says scientists do not yet know why the rates are rising.

## Why it matters

The reversal of a two-decade decline in a common cancer changes which age groups screening and risk research should focus on, and the unexplained cause leaves prevention guidance open.

## Timeline

- 2026-11-11: Study findings on rising US colorectal cancer rates reported in a ScienceDaily release

## Coverage

- [Colorectal cancer is rising again after 20 years, and scientists don't know why](https://www.sciencedaily.com/releases/2026/11/261111005843.htm) — Health & Medicine News -- ScienceDaily, 2026-11-12

Tags: colorectal cancer, epidemiology, public health, cancer rates, screening

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Brief generated by AI (claude-haiku-5-5) from the reporting listed under Coverage. Headlines belong to their publishers. The Morning Science – https://themorning.science