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What is a Colon Biopsy?

The Definitive Test for Colon Cancer

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Updated February 15, 2012

A colon biopsy is an exam that tests tissue samples from your colon. The doctor is looking for abnormal tissues, such as cancerous or pre-cancerous cells. Keep in mind –- just because your doctor ordered a biopsy does not mean you have cancer.

Why Biopsies are Ordered

Your doctor found an irregularity in one of your colon cancer screening exams. The only way to definitively tell if the abnormality is cancerous is by extracting tissue and taking a look at it under a microscope. If abnormalities were found during a sigmoidoscopy or a colonoscopy, the doctor can extract tissues during that same test. If irregularities (tumors, masses, blood in stool) were found during another screening test (double contrast barium enema or fecal occult blood tests), you will be scheduled for a colonoscopy.

CT-Guided Versus Colonoscopy

There are different approaches to the biopsy procedure, which are dependent on where the irregular tissues were found. The most common way to obtain a biopsy of the colon is through a colonoscopy. However, if your doctor found abnormalities on your computed tomography (CT) scan that were not isolated in the colon, he or she may order a CT-guided biopsy.

A CT-guided biopsy, also called a needle or CT-guided needle biopsy, is completed in the CT room at the hospital or clinic. This type of biopsy is most frequently ordered when masses are found outside of the colon, including those in the lungs, liver or pelvis. The doctor uses the CT scanner to pinpoint the abnormal area, inserts a needle into the mass in question, and extracts tiny tissue samples. You can go back to work the same day, won’t need sedation, and the entire process takes about one hour.

If the irregular tissues are confined to your colon, your doctor will order a colonoscopy to take the biopsy. The colonoscopy uses a lighted probe, called a colonoscope, to visualize the interior of your colon. This flexible probe allows the passage of specialized instruments that can retrieve (clip) a sample of tissue from your colon for the biopsy.

Preparing for Your Colon Biopsy

The colonoscopy preparation requires a complete bowel preparation prior to the procedure. Your doctor may order a combination of liquid laxatives, suppositories, or an enema to cleanse the inside of your colon. This cleansing procedure makes the lining of your colon visible by flushing out fecal matter and fluids in the large intestine. Talk to your doctor if you are diabetic or take prescription medications, especially blood thinners, as your doctor may have special orders for you prior to the exam.

Potential Complications and Risks

Like any medical procedure, a colon biopsy is not devoid of risks. However, the sooner you learn if you have colon cancer, the sooner you can begin treatment. Your doctor will discuss the risks versus the benefits with you before the procedure. Be sure to ask questions if the procedure details are not clear. The potential risks of a colon biopsy include:

  • Bleeding
  • Infection
  • Bowel perforation
  • Hospitalization
  • Postpolypectomy syndrome
  • Failed colonoscopy
  • Complications from weaning off of blood thinners prior to exam
  • Complications from anesthesia

If you have a complex medical history or are elderly, your risk factors may increase. Discuss any prescription or over-the-counter medications with your doctor prior to the procedure. A nurse or staff member from the hospital or clinic may call you to review instructions prior to your procedure.

What Will Happen? Will it Hurt?

In all likelihood, you will be sedated for the colonoscopy and biopsy; therefore, you shouldn't feel a thing. Following the procedure, you will be taken to a recovery area, where the staff will monitor you until you are awake and alert. Due to the sedation, you will not be allowed to drive yourself home, even if you feel up to it. Your judgment is considered officially impaired for 24 hours following sedation (don’t sign any legal documents, either). Air was inserted into your colon during the procedure, which may cause some cramping and passing gas.

Do not hesitate to contact your doctor if you develop a fever, shaking, chills, abdominal pain, dizziness or notice blood in your stools following the biopsy.

Waiting for Results

Immediately following your biopsy, the tissue sample is shipped off to the pathologist. A pathologist is a special M.D. (medical doctor) who examines tissues and blood under a microscope. The pathologist will need time to examine your tissue sample thoroughly, and then he or she will construct a pathology report. The report describes if the tissues obtained were normal or cancerous, and will help your doctor decide the staging and grade of your cancer.

Preferably before the procedure (as you may not remember afterwards), ask your doctor when you can expect results. He or she will be able to give you a ballpark figure and encourage you to make a follow-up appointment.

Getting Your Results

Once your doctor receives your biopsy result from the pathologist, he or she will call you. If you do not already have an appointment to discuss these results, one will be scheduled for you at this time. The doctor will want to discuss your results in person –- not over the phone or by email. Although the wait may produce some severe anxiety, it is better to sit down and talk with your doctor about results face-to-face.

What the Pathology Report Says

Your doctor has the medical background and training to explain your pathology report to you. The pathologist’s report will include:

  • Where the lesion(s) were located -– anatomically in the colon

  • Histology –- type of cells found, such as normal (benign) or malignant (cancerous). If malignant, the report will display the cancer type (adenocarcinoma is the prevalent colon cancer type).

  • Grade -– This is what the doctor uses to stage your cancer. The grade explains how mutated the tissues are (are they somewhat similar to regular colon tissue, not identifiable at all, or some grade in between).

  • Invasion -– If your tissue was taken during surgery for colon cancer, the surgeon will send the extracted piece of bowel to the pathologist, who will then determine how far the cancer spread into healthy tissues.

Do not hesitate to ask your doctor and nurses questions at any point along the way. The medical professionals are there to assist you.

Sources:

American Cancer Society. (2006). American Cancer Society's Complete Guide to Colorectal Cancer. Clifton Fields, NE: American Cancer Society.

American Society for Gastrointestinal Endoscopy. (2012). Colonoscopy. Accessed February 1, 2012.

National Cancer Institute. (May 2011). DChemotherapy Side Effects: Appetite Changes.. Accessed February 1, 2012.

Lange, V. (2009). Be a Survivor. Colorectal Cancer Treatment Guide. (4th ed.). Los Angeles: Lange Productions.

Levin, T.R., Zhao, W., Conell, C., et al. (December 2006). Complications of Colonoscopy in an Integrated Health Care Delivery System. Annals of Internal Medicine; 145. Accessed February 6, 2012.

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