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Gas and Bloating as Symptoms of Colon Cancer


Updated: June 22, 2008

Gas and bloating may result from innocuous things like swallowing too much air or eating too much sugar. However, gas and bloating can also be symptoms of colon cancer or intestinal disorders like irritable bowel syndrome (IBS).

Common Causes of Gas and Bloating

Gas comes from two main sources: swallowed air and the normal breakdown of undigested food -- especially sugar, starches, and fiber. Our bodies expel this gas by belching and "breaking wind." I'm not sure why we laugh at other people for doing those things since we all do it! In fact, when our bodies are functioning normally, we pass gas 14 to 23 times a day. Maybe we should stop hiding it so we can all laugh more. (I'll start after you do.)

Bloating can be caused by too much gas in the intestines, but usually people who complain of bloating have normal amounts of gas. Doctors believe that feeling bloated is often the result of an intestinal disorder (such as IBS), which makes people more sensitive to the presence of gas in their intestines.

Gas and Bloating as Symptoms of Cancer

Sometimes a tumor causes a bowel obstruction, which is basically a roadblock in the colon. Depending on the severity of the blockage, solids, liquids, and even gas may be prevented from passing by.

A pattern of gas and bloating may be an indication that a tumor is growing in the colon and occasionally causing a blockage. This is because even if the tumor isn't large enough to cause a bowel obstruction on its own, stool may periodically get hung up on the tumor while it's passing by. Thereby, it causes a temporary bowel obstruction.

While the bowel is blocked and air is trapped, bloating occurs. This is because air is trapped in a confined space and presses on the walls of the colon. This will likely result in stomach cramping and a noticeable decrease in the number of times you pass gas on any given day. When the blockage resolves itself, all that backlogged air makes a swift and unapologetic exit in the form of flatulence.

Medical Attention for Gas and Bloating

A bowel obstruction can be a medical emergency, particularly if the blockage is restricting blood flow to the colon. Many people have received a surprise colon cancer diagnosis after a trip to the emergency room.

If you have chronic gas and bloating, talk to your doctor, especially if it is accompanied by other symptoms of colon cancer. Treating yourself with over-the-counter remedies may relieve your gas and bloating, but it allows the underlying cause to remain undiagnosed. With a physical exam, abdominal x-rays, and/or a barium enema, your doctor can determine if a blockage exists, and if so, where it's located.

Related Articles:


"Gas in the Digestive Tract." National Institutes of Health Mar. 2004. Accessed 28 Aug. 2007 [http://digestive.niddk.nih.gov/ddiseases/pubs/gas/index.htm].

"Gastrointestinal Complications." National Cancer Institute 19 Jul. 2006. Accessed 28 Aug. 2007 [http://www.cancer.gov/cancertopics/pdq/supportivecare/gastrointestinalcomplications/Patient/page5].

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