People who have any of the risk factors described under “Colorectal Cancer: Who’s at Risk?” should ask a doctor when to begin checking for colorectal cancer, what tests to have, and how often to have them. The doctor may suggest one or more of the tests listed below. These tests are used to detect polyps, cancer, or other abnormalities, even when a person does not have symptoms. Your health care provider can explain more about each test.
- A fecal occult blood test (FOBT) is a test used to check for hidden blood in the stool. Sometimes cancers or polyps can bleed, and FOBT is used to detect small amounts of bleeding.
- A sigmoidoscopy is an examination of the rectum and lower colon (sigmoid colon) using a lighted instrument called a sigmoidoscope.
- A colonoscopy is an examination of the rectum and entire colon using a lighted instrument called a colonoscope.
- A double contrast barium enema (DCBE) is a series of x-rays of the colon and rectum. The patient is given an enema with a solution that contains barium, which outlines the colon and rectum on the x-rays.
- A digital rectal exam (DRE) is an exam in which the doctor inserts a lubricated, gloved finger into the rectum to feel for abnormal areas.
Common signs and symptoms of colorectal cancer include:
- A change in bowel habits
- Diarrhea, constipation, or feeling that the bowel does not empty completely
- Blood (either bright red or very dark) in the stool
- Stools that are narrower than usual
- General abdominal discomfort (frequent gas pains, bloating, fullness, and/or cramps)
- Weight loss with no known reason
- Constant tiredness
These symptoms may be caused by colorectal cancer or by other conditions. It is important to check with a doctor.