Screening is a way to evaluate people without symptoms to determine if they are at risk for cancer or have already developed cancer.

Screening Guidelines

The decision to screen for colorectal cancer will likely be made on an individual basis based on your risk factors. The American Cancer Society suggests the following guidelines:

For people at average risk

Beginning at age 50:

For people with a first degree relative with onset of colorectal cancer after age 60:

  • Begin screening at age 40
  • Preferred screening: colonoscopy every 10 years

For people with a first degree relative with onset of colorectal cancer before age 60:

  • Begin screening at age 40, or 10 years younger than age of diagnosis of the affected relative (whichever is first)
  • Preferred screening: colonoscopy every 3 to 5 years

For people with a family history of familial adenomatous polyposis (FAP):

  • Begin screening at puberty via endoscopy .
  • Genetic testing recommended. If genetic test is positive, colectomy (removal of part of the colon) should be considered.

For people with a family history of hereditary non-polyposis colon cancer (HNPCC):

Colonoscopy starting at age 21.

Genetic counseling recommended. If genetic test is positive, or patient has not had genetic testing, colonoscopy every 1-2 years until age 40, then annually.

Screening Tests for Colorectal Cancer

Digital Rectal Exam

This exam is done manually to check for abnormal lumps or growths in the rectal area. To do this test, your doctor inserts a lubricated gloved, finger into the rectum, and gently probes for any growths. The exam takes only a few minutes and is performed in the doctor’s office. It should be done in conjunction with other screening tests, because often times a cancer is located far above the tip of the finger.

Fecal Occult Blood Test (FOBT)

This test identifies the presence of occult (hidden) blood in the stool, which would signify bleeding, possibly caused by the presence of a tumor.

For this test, you will be given instructions and a kit to prepare the stool sample in your own home. You will place a small sample of stool on a special card. The card will be sent to a lab that will test the sample for hidden blood. Your doctor will tell you that you must avoid certain foods, especially those rich in iron, before getting this test otherwise a false positive result may appear.

Sigmoidoscopy

This test enables the doctor to view the inside of the lower colon and rectum for polyps, tumors, or abnormal growths.

A day or two prior to the test, you will need to completely eliminate all waste from your lower intestine. This is usually done by drinking a medication that acts as a laxative, or by having an enema (a substance that is squirted into the rectum and causes bowel movements). On the day of the test, you will be given a sedative to ease discomfort. The doctor will insert a sigmoidoscope (a thin, lighted flexible tube with a tiny camera attached) into the rectum and bowel. The camera transmits the image of your rectum onto a video screen, which allows your doctor to view and examine the inside of the rectum to look for abnormalities.

The doctor will give you a preliminary report of the results when the sigmoidoscopy is completed.

Colonoscopy

This test enables the doctor to view the inside of the entire colon and rectum for polyps, tumors, or abnormal growths.

A day or two prior to the test, you will need to completely eliminate all waste from your lower intestine. This is usually done by drinking a medication that acts as a laxative, or by having an enema (a substance that is squirted into the rectum and causes bowel movements). On the day of the test, you will be given a sedative to ease discomfort. The doctor will insert a colonoscope (a thin, lighted flexible tube with a tiny camera attached) into the rectum and bowel. The camera transmits the image of your colon onto a video screen, which allows your doctor to view and examine any abnormalities inside the colon.

If a polyp or abnormal tissue is discovered during this exam, it may be removed and reviewed for further testing. If tissue is removed, a small amount of bleeding may occur during the first two days after the procedure. This procedure takes less than one hour and is usually done in a hospital or doctor’s office.

The doctor will usually give you a preliminary report after the medication wears off and you are more alert. The results from a biopsy can take as long as one to two weeks to be completed, so schedule a follow-up appointment with your doctor.

Barium Enema

A barium enema is a rectal injection of barium given to coat the lining of the colon and rectum. It is done before x-rays are taken in order to create better x-ray images. X-rays are taken of the colon and/or rectum to look for polyps, abnormal growths, or a thickening of the lining of the colon or rectum.

For this procedure, a well-lubricated enema tube is gently inserted into the rectum. Barium is injected through this tube into the colon and rectum. A small balloon at the end of the tube is inflated to keep the barium inside. X-rays are taken. After x-rays are taken, the enema tube is removed, and you are shown to the bathroom to expel the barium. The procedure will last one to two hours.

Endoscopy

The insertion of a fiberoptic tube with a lighted tip (an endoscope) through the mouth and down through the gastrointestinal (GI) tract to examine the GI tract. This allows your doctor to look for abnormalities, and perhaps to obtain a biopsy specimen of suspicious tissue.