Biopsy for Colorectal Cancer

Beginning at age 50, you should have routine screenings every 10 years for colon or rectal cancer. You'll have either a sigmoidoscopy or a colonoscopy. Both these procedures use a thin flexible tube to look inside the colon. A colonoscopy takes a look at your entire colon. A sigmoidoscopy looks at a portion of it. You'll take medication to make you sleepy and relaxed before either procedure.


If a doctor sees anything inside your colon or rectum that looks questionable, he'll take a biopsy to find out if it's cancerous. A biopsy is a routine type of test used to diagnose cancer and also to see whether an existing cancer has spread to the surrounding tissue.

The doctor uses a special instrument to take out a small sample of tissue. You won't feel anything. The sample is sent to a lab to determine if there's any cancer. The screening and biopsy together take less than an hour.

Sometimes doctors use a tiny needle to take a biopsy, and they may use a CT scan or ultrasound to guide them. A CT scan is a powerful X-ray that takes detailed pictures of the inside of your body. An ultrasound makes images using soundwaves.

After a Biopsy

You'll go home the same day as your procedure. You can expect to feel some discomfort and have some light bleeding for a day or two. Serious complications are rare, but it is possible to get an infection or injury to your colon or rectum.

Contact your doctor right away if you have:

  • Fever or chills
  • Heavy bleeding (greater than a teaspoon at a time)
  • Severe pain
  • Vomiting

The Results

It may take a few days to get the results of your biopsy. If you do have cancer, the doctor will determine how aggressive it is and whether it started in your colon or spread there from somewhere else.

You may need additional testing before you and your doctor can determine the best treatment plan.

WebMD Medical Reference Reviewed by William Blahd, MD on September 06, 2016



American Cancer Society: "Colorectal cancer screening tests," "Frequently Asked Questions About Colonoscopy and Sigmoidoscopy." "Colorectal Cancer -- Diagnosis."

National Center for Biotechnology Information: "Colorectal Cancer: The Diagnosis and Management of Colorectal Cancer."

University of Mississippi Medical Center: "Colorectal Cancer Biopsy & Pathology."

Mayo Clinic: "Types of biopsy procedures used to diagnose cancer." "Colonoscopy."

University Hospitals Seidman Cancer Center: "Colonoscopy."

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