Colorectal Cancer Screening

What is a colorectal cancer screening?

Your doctor may recommend tests to examine your colon and rectum to detect colon cancer before symptoms occur. The exams are:

Fecal occult blood test. This test chemically checks your stool for hidden (occult) blood, which can only be detected through chemical testing. This test may be done in your doctor's office or you may be given a kit to use at home. At the lab, a chemical is applied to the specimen. The chemical reacts with the stool sample and appears as a different color if it comes in contact with blood. If blood is found, you will need additional tests to determine the cause.

Flexible sigmoidoscopy. Your doctor will examine the lower portion of your colon by inserting a thin, flexible tube called a sigmoidoscope into your rectum. This procedure usually takes about 15 minutes. Sigmoidoscopy may be done in conjunction with a colon X-ray.

Colon X-ray (double contrast barium enema). Liquid barium, a solution that looks bright white on X-ray images, is put into your colon by way of a slender tube inserted into your rectum. The barium outlines the inner surface of your colon, allowing the X-ray to detect any irregularities. This test typically takes about 20 minutes and can cause abdominal cramping. It may be done in conjunction with flexible sigmoidoscopy.

Colonoscopy. Your doctor will examine the entire length of your colon using a thin, flexible colonoscope inserted into your rectum. The procedure is similar to a flexible sigmoidoscopy, although the instrument is longer so that your doctor can view your entire colon. This procedure takes about 30 minutes. It can be uncomfortable, so it's generally done using a type of sedation that uses pain relievers and sedatives to minimize discomfort.

Why should I get screened for colorectal cancer?

To detect cancer and benign growths (polyps) on the inside wall of your colon that may become cancerous. Getting polyps removed may reduce your risk of colorectal cancer. 

How often should I get a colorectal cancer screening?

Not everyone needs to be tested for precancerous polyps and colorectal cancer. Your need for screening depends on your level of risk. Three major factors put you at higher risk of developing colorectal cancer:

  • Age 50 or older
  • Family or personal history of colorectal cancer or adenomatous polyps
  • Personal history of inflammatory bowel disease

If you're age 50 or older and at average risk, the American Cancer Society recommends that you follow one of these five recommendations:

  • Fecal occult blood test every year
  • Flexible sigmoidoscopy every five years
  • Fecal occult blood test every year plus flexible sigmoidoscopy every five years
  • Double contrast barium enema every five years
  • Colonoscopy every 10 years

Talk to your doctor about which screening approach and frequency are best for you based on your particular health issues.

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