Information: Colorectal Cancer Screening
Colorectal cancer screening means checking your colon and rectum for early signs of cancer or polyps before you feel sick. Screening is important because it can find cancer early, when it is easiest to treat, and some tests can even prevent cancer by finding and removing polyps.
Main types of screening tests:
Stool-based tests (at-home tests)
These tests are done at home. You collect a small poop sample and mail it to a lab. They are easy and do not require a special diet or colon cleaning.
- FIT / FOBT: Looks for tiny amounts of hidden blood in your stool. Done every year.
- Stool DNA test (like Cologuard): Checks for hidden blood and abnormal DNA from cancer or polyps.
If an at-home test is not normal, you will need a colonoscopy to find out why.
Visual exams (done in a clinic)
These tests let a doctor look inside your colon. You must do a bowel prep the day before to clean out your colon.
- Colonoscopy: The most complete test. A doctor uses a flexible tube with a camera to look at the whole colon and can remove polyps at the same time. You are usually sedated (made sleepy and relaxed).
- Flexible sigmoidoscopy: Similar, but only looks at the lower part of the colon.
- CT colonography (virtual colonoscopy): A CT scan takes pictures of your colon. No sedation, but still requires bowel prep. If something looks abnormal, a regular colonoscopy is needed.
Blood test option
A newer blood test called Shield was recently approved by the FDA for average-risk adults. It is still being studied before it becomes part of all screening guidelines.
The most important thing
Get screened with any test you and your healthcare provider decide is right for you. Regular screening saves lives. You and your provider can choose the best option based on your health and risk factors.
The information is adapted from National Comprehensive Cancer Network. (2025). NCCN Clinical Practice Guidelines in Oncology: Colorectal Cancer Screning and Diagnosis (Version 2.2025). Available at https://www.nccn.org/ text generated by Gemini.” Gemini, Google, 19 Nov 2025 and from OpenAI on 11/19/2025 using “what is colorectal cancer screening in plain language”
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