DATA CHECKED NOVEMBER 6, 2026

Choose an age group to see observed yearly diagnosis rates through 2023. This SEER 21 series excludes appendix cancers and is separate from the SEER 12 all-age series in the recent-data view.

U.S. REGISTRY DATA · 2000–2023

How diagnosis rates
have changed over time

5.9 in 2000 9.9 in 2023

New diagnoses per 100,000 people, age-adjusted

Under 50: observed colorectal cancer diagnosis rates, 5.9 per 100,000 in 2000 and 9.9 in 2023. SEER 21, colon and rectum excluding appendix. Year-by-year values are available below.0369122000: 5.9 per 100,0002001: 5.8 per 100,0002002: 5.9 per 100,0002003: 5.9 per 100,0002004: 6.1 per 100,0002005: 6.1 per 100,0002006: 6.3 per 100,0002007: 6.5 per 100,0002008: 6.4 per 100,0002009: 6.5 per 100,0002010: 6.6 per 100,0002011: 6.6 per 100,0002012: 6.5 per 100,0002013: 6.6 per 100,0002014: 6.9 per 100,0002015: 7.0 per 100,0002016: 7.0 per 100,0002017: 7.3 per 100,0002018: 7.3 per 100,0002019: 7.5 per 100,0002020: 7.3 per 100,0002021: 8.3 per 100,0002022: 9.0 per 100,0002023: 9.9 per 100,000200020102023Under 50: observed colorectal cancer diagnosis rates, 5.9 per 100,000 in 2000 and 9.9 in 2023. SEER 21, colon and rectum excluding appendix. Year-by-year values are available below.0369122000: 5.9 per 100,0002001: 5.8 per 100,0002002: 5.9 per 100,0002003: 5.9 per 100,0002004: 6.1 per 100,0002005: 6.1 per 100,0002006: 6.3 per 100,0002007: 6.5 per 100,0002008: 6.4 per 100,0002009: 6.5 per 100,0002010: 6.6 per 100,0002011: 6.6 per 100,0002012: 6.5 per 100,0002013: 6.6 per 100,0002014: 6.9 per 100,0002015: 7.0 per 100,0002016: 7.0 per 100,0002017: 7.3 per 100,0002018: 7.3 per 100,0002019: 7.5 per 100,0002020: 7.3 per 100,0002021: 8.3 per 100,0002022: 9.0 per 100,0002023: 9.9 per 100,000200020102023
NCI SEER Explorer, SEER 21 registry areas; both sexes, all races/ethnicities. Colon and rectum, excluding appendix. Observed annual rates; data end in 2023. The gray 2020 point reflects a year affected by diagnosis disruptions. The vertical scale changes with the age selection and always starts at zero.
Read annual values and methods
Under 50 · observed rates per 100,000
YearDiagnosis rate
20005.9
20015.8
20025.9
20035.9
20046.1
20056.1
20066.3
20076.5
20086.4
20096.5
20106.6
20116.6
20126.5
20136.6
20146.9
20157.0
20167.0
20177.3
20187.3
20197.5
20207.3
20218.3
20229.0
20239.9

Rates are age-adjusted to the 2000 U.S. standard population. Lines connect the source’s annual observations; they are not fitted forecasts. These estimates describe the SEER registry areas and are not a personal risk calculator.

Download annual values (JSON)

Source for recent trends, demographics, and 2026 estimates: NCI SEER Cancer Stat Facts. Download the source-reported values (JSON).

ACS and SEER views have different time windows and definitions; they are presented separately and are not joined into one series.

What the age-trend numbers show

Colorectal cancer includes cancer of the colon and rectum. In the United States, new-diagnosis rates fell by about 1% annually overall from 2013 to 2022, while rising by 2.9% annually in adults under 50 and 0.4% in adults aged 50–64, according to the American Cancer Society. A national decline can coexist with increases in younger age groups.

These are changes in population diagnosis rates, not a person's probability of developing cancer. They are not a forecast. The source was published in 2026, but the observed trend ends in 2022; cancer-registry reporting takes time.

Why is this happening?

There is no single established explanation for the rise. A factor associated with an individual's risk does not automatically explain a population trend. Researchers are studying how exposures across a lifetime may interact.

Established risk factors

The CDC identifies older age, family or personal history, certain inherited syndromes, inflammatory bowel disease, tobacco, alcohol, physical inactivity, and excess body weight among colorectal cancer risk factors. Their importance differs between people. Having cancer is not evidence that someone made poor choices, and people without these factors can develop it.

Diet, metabolism, and inflammation

Researchers are examining dietary patterns, metabolic health, and inflammatory processes, including how these interact with other exposures. These are plausible contributors, not a complete explanation for the increase in younger adults. Observational associations cannot establish which exposure caused an individual's cancer.

Gut bacteria and early-life exposures

A 2025 international genomic study found DNA mutation patterns linked to colibactin, a toxin made by some gut bacteria, more often in younger colorectal cancer patients. The findings support an early-life exposure hypothesis. They do not establish that one bacterium accounts for the whole rise or that a consumer microbiome test can predict a person's cancer risk.

Screening and detection

Changes in screening, diagnostic practice, and access to care can affect measured incidence. Researchers consider these alongside biological and environmental explanations. A rise in recorded diagnoses alone cannot tell us how much each factor contributes.

What remains uncertain

The relative contributions of different exposures, when they matter most, and why trends differ between populations remain open questions. A headline about a new association is a clue to investigate, not a proven prevention treatment. This page will need updating as evidence develops.

A useful next step

Discuss your screening schedule and family history with a clinician. In the U.S., average-risk screening generally starts at 45; some people need an earlier plan. Blood in the stool, a persistent bowel change, or unexplained weight loss deserves medical evaluation at any age. Do not wait for screening eligibility to discuss symptoms.

This is general education for U.S. readers, not a diagnosis or a personal screening plan. Talk with your clinician about your own history and symptoms. Follow your clinic’s instructions.

Sources & further reading