- Having diarrhea or constipation
- Feeling that your bowel does not empty completely
- Finding blood (either bright red or very dark) in your stool
- Excreting stool that is narrower than usual
- Frequently having gas pains or cramps, or feeling full or bloated
- Losing weight for no known reason
- Feeling tired all the time
- Vomiting or experiencing nausea
Most often, these symptoms are not due to cancer. Other health problems can cause the same symptoms. Anyone with these symptoms should see a doctor to be diagnosed and treated as early as possible. Usually, early cancer does not cause pain. It is important not to wait to feel pain before seeing a doctor.
If you have screening test results that suggest cancer or if you have symptoms, your doctor must find out whether they are due to cancer or some other cause. Your doctor will ask about your personal and family medical history and will give you a physical exam. You may have one or more of the tests described in the “Screening” section.
If your physical exam and test results do not suggest cancer, your doctor may decide that no further tests are needed and that no treatment is necessary. However, your doctor may recommend scheduled check-ups.
If tests show an abnormal area (such as a polyp), a biopsy, to check for cancer cells, may be necessary. Often, the abnormal tissue can be removed during colonoscopy or sigmoidoscopy. A pathologist will check the tissue for cancer cells using a microscope.
Source: The Web site of the National Cancer Institute (http://www.cancer.gov)