The first question is whether you need routine screening or an investigation of symptoms. Screening looks for cancer or precancerous changes before symptoms appear. Blood in the stool, a persistent bowel change or another concern calls for a clinical assessment, whatever your age or screening history.
Colorectal cancer includes cancers of the colon and rectum. This guide explains the screening pathway and the questions that help you move from a test result to an appropriate next step.
Start with symptoms and personal risk
Tell a clinician about blood in the stool, an ongoing change in bowel habits, persistent abdominal discomfort or unexplained weight loss. These can have causes other than cancer; evaluation establishes what is happening. The NCI colon-cancer guide describes symptoms and diagnostic testing.
Bring previous colonoscopy and polyp reports if you have them. Describe relatives with colorectal cancer or significant polyps, their relationship to you and the age at diagnosis when known. A history of polyps, inflammatory bowel disease or an inherited syndrome can change the recommended pathway. Ask the clinician to distinguish average-risk screening, higher-risk screening and surveillance after a previous finding.
Use the family-history and inherited cancer-risk guide to organize relatives’ diagnoses and questions about genetic counseling.
Use a named screening recommendation
For U.S. adults without symptoms who meet its average-risk criteria, the USPSTF recommends screening from ages 45 through 75. From 76 through 85, decisions are selective and take account of health, prior screening and preferences. Higher-risk histories require an individualized discussion.
Screening is a process: choose a suitable test, complete it correctly, receive the result and arrange indicated follow-up. The best fit is one you can complete and repeat as needed, with access to colonoscopy if another screening test is abnormal.
Compare the practical commitments
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| Option | Usual interval in USPSTF guidance | What completing it involves |
|---|---|---|
| FIT stool test | Every year | Collect a sample at home using the kit instructions; an abnormal result requires colonoscopy. |
| Stool DNA-FIT | Every 1–3 years | Collect a stool sample at home; an abnormal result requires colonoscopy. |
| Colonoscopy | Every 10 years | Bowel preparation, an examination of the full colon, and usually sedation; polyps can be removed. |
| CT colonography | Every 5 years | Bowel preparation and CT imaging; certain findings require colonoscopy. |
These intervals describe routine screening after an appropriate negative result; prior findings or test quality can change the next date. Other accepted strategies include flexible sigmoidoscopy. Ask about the specific test offered, its evidence, limitations and local availability.
The NCI screening comparison explains that stool tests, endoscopic procedures and imaging differ in what they detect and how follow-up works. Some tests can miss a cancer or lead to further testing when cancer is absent. Colonoscopy has risks, including bleeding and perforation, as well as the practical burden of preparation.
Know what an abnormal result requires
A positive stool screening result is a reason for a colonoscopy to find the cause. Repeating the stool test to look for a reassuring result does not complete that follow-up. Ask the ordering service to arrange the next step and explain the timing.
When a colonoscopy removes a polyp or takes a biopsy, the laboratory report helps determine what the tissue is and when further care is needed. Ask who will give you that report and your next recommended examination date. The word “polyp” alone does not establish cancer.
Plan around the test instructions
For colonoscopy, obtain the service's written bowel-preparation and medication instructions early. Tell them about all medicines and health conditions; ask specifically how to manage any medicine that needs a temporary adjustment. Follow their schedule rather than combining instructions from different websites.
NIDDK's colonoscopy guide explains preparation, sedation, transport and recovery. If sedation is planned, arrange the required ride home. If you cannot finish the preparation or cannot attend, contact the service for instructions. Afterward, keep the discharge advice, including the symptoms that need prompt medical attention.
Download the screening and follow-up planner to record the chosen test, preparation questions, reporting contact and next step.
If cancer is found, ask what determines the plan
Ask for the exact location, pathology and stage. A colon cancer and a rectal cancer may need different planning even though both are colorectal cancers. The team considers how far disease extends, tumor features, general health and treatment goals when recommending surgery, medicines or other treatment. The NCI treatment guide provides an orientation to colon-cancer care.
Ask whether tumor or inherited-risk testing is indicated, whether relatives need advice, and whether a multidisciplinary review or second opinion would help. Keep nutrition, symptom relief and practical support in the conversation. A prevention study about a pain reliever or vitamin cannot select treatment for a diagnosed cancer; medication decisions belong with your care team.
The guide to cancer spread and staging explains the terms you may encounter when discussing the extent of a diagnosis.
Updated October 9, 2026. General education for preparing conversations with qualified health professionals; your care plan depends on your own history and test results.
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