# SEER data: US colorectal cancer incidence rose to 38.3 per 100,000 in 2023 after falling from 55.2

- Published: 2026-11-05 15:41 UTC
- Section: Life & Health › Medicine
- Tags: colorectal cancer incidence, SEER 21, age-adjusted rate, colorectal cancer screening, birth cohort effect, NEJM Evidence, cancer registry data, colon organoids
- URL: https://realtech.media/news/rt-70217efeab66c3519526a784_seer_data_us/

**An analysis of SEER data shows the age-adjusted colorectal cancer rate in the US rose in 2023, the first increase since SEER 21 began; the authors call for further surveillance.**

Researchers led by Caitlin Murphy of the University of Chicago analyzed US colorectal cancer incidence between 2000 and 2023 using the National Cancer Institute's SEER Program, according to a paper in NEJM Evidence. [1] The SEER 21 registries cover 45.8% of the U.S. population. The age-adjusted incidence rate was 55.2 per 100,000 in 2000, 36.7 per 100,000 in 2022 and 38.3 per 100,000 in 2023. [1]

The authors describe the rise in 2023 as apparent and as the first since the inception of SEER 21. They say it warrants additional surveillance and investigation. [1] Murphy said this is the first increase in the overall rate in more than 20 years.

## Age groups and screening

According to the study, the increase is not limited to adults younger than 50. Incidence is rising among people ages 65 to 69 and has stopped declining among those ages 70 to 74, even though about 80% of people in these groups are up to date with screening. [1]

The steepest rise was among adults ages 45 to 49: incidence grew 12.76% annually between 2019 and 2023. The researchers believe this largely reflects expanded screening after national guidelines lowered the recommended starting age from 50 to 45, since screening can reveal cancers that were already present. Screening alone does not explain the wider rise, especially among older adults with high participation.

The authors also checked the effect of the COVID-19 pandemic. The increase persisted when data from 2020 and 2021 were excluded, and screening had largely returned to pre-pandemic levels by January 2021.

## Possible causes

The causes remain uncertain. Murphy suggests a birth cohort effect, in which people born in the 1960s and afterward may carry an elevated risk into older age. American Cancer Society statistics show that incidence among people ages 20 to 49 rose approximately 3% annually from 2013 to 2022.

Murphy is working with toxicologist Xin Hu of Emory University to examine thousands of environmental chemical exposures using small blood samples. The team then plans, together with Sonia Kupfer, to study selected chemicals in colon organoids, laboratory-grown models that reproduce some features of human colon tissue. No specific exposure has been established as responsible for the observed trends.

Current national guidelines recommend routine screening for adults at average risk from age 45 through age 75.

## Sources

1. [NEJM Evidence](https://doi.org/10.1056/EVIDpha2600217)
2. [SciTechDaily](https://scitechdaily.com/scientists-sound-the-alarm-as-colorectal-cancer-reverses-a-20-year-decline)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-70217efeab66c3519526a784_seer_data_us/