Any cancer of the pelvis or abdomen can cause a bowel obstruction, but most commonly it is associated with cancers of the stomach, ovaries and colon. A bowel obstruction is a partial or complete blockage of the passageway for stool removal. It can occur in your small or large intestines. Bowel obstructions from colon cancer usually occur in the large intestine (the colon).
What Causes It?
Bowel obstructions caused by colon cancer are classified as mechanical obstructions. This means that there usually isn't anything wrong with the muscular tone or blood supply to your colon. Rather, the blockage is caused by a growing mass inside the colon. Imagine inserting a golf ball into your garden hose -- water will not be able to pass the golf ball and will eventually start to back up. The painful symptoms of a bowel obstruction result from the tumor blocking stool -- the bowel swells and the inflammation can cause pain.
In advanced colon cancer, bowel obstructions can occur more than once, especially if you have had prior abdominal surgery or radiation therapy. Both of these cancer treatments increase your risk of developing an obstruction at some point.
Symptoms and Prevention
The best way to prevent a bowel obstruction from a growing tumor is by following screening guidelines and getting routine colonoscopies. Although I've provided a list of symptoms associated with obstruction, they are vague and not specific only to bowel obstructions from colon cancer. If you have any upsetting symptoms or think you have a bowel obstruction, you need to talk to your physician. Some symptoms that may occur with a bowel obstruction include:
- Intermittent cramping, colicky pain in your abdomen
- Decreasing appetite
- Bowel movement changes
- Chronic constipation or lack of a bowel movement
- Abdominal distention
- Collecting fluid in your abdomen
Visiting Your Doctor
Your doctor can perform a physical examination to check your abdomen, bowel sounds, blood and urine labs. If he or she is concerned about a potential obstruction (either partial or complete), the doctor may order a computed tomography (CT) scan of your abdomen along with x-rays to look for a blockage. They may or may not include a barium enema, which involves inserting a small amount of contrast material into your rectum to help better visualize the structures.
If the radiologist finds a blockage, your doctor may also order a scope, such as a sigmoidoscopy or colonoscopy, to visualize the blockage.
Your doctor will take many factors into consideration before discussing your treatment options with you. He or she will consider your:
- Age and general health
- Nutritional status
- Stage and grade of your cancer
- Other illnesses (such as diabetes or lung disease) that may decrease your chances of a successful surgery and recovery
- Prior cancer treatments (surgery or radiation to the area, which could be complicating)
Surgery to physically remove the blockage is usually the treatment option of choice, unless the bowel obstruction is chronic (keeps coming back) or your cancer is so advanced that you would be unable to tolerate surgery. The surgeon may need to insert a permanent or temporary colostomy, which is an artificial opening in your abdomen for stool evacuation.
If the blockage cannot safely be removed, the doctor will initiate measures to keep you comfortable, which is known as palliative care. One option includes placing a rigid metal coil called a stent into the area of obstruction to hold it open for stool passage. Your doctor can also order medications to reduce the pain and symptoms associated with the blockage.
Complications of bowel surgery are one potential risk that you must consider carefully and can include infection, bleeding, perforation (a hole in the bowel), re-obstruction, and movement of the stent. However, bowel obstructions are usually deadly if they are not treated. Ask your doctors to explain all of the potential risks of surgery and ask questions if you do not understand something.
American Cancer Society. (2006). American Cancer Society’s Complete Guide to Colorectal Cancer. Clifton Fields, NE: American Cancer Society.
American Cancer Society. (n.d.). Managing Symptoms of Advanced Cancer. Accessed July 15, 2012.
Ripamonti, C.I., Easson, A.M., & Gerdes, H. (2008). Management of Malignant Bowel Obstruction. European Journal of Cancer (44). Accessed July 16, 2012.
National Cancer Institute. (n.d.). Bowel Obstruction. Accessed July 16, 2012.