Gas and Bloating Can Be Symptoms of Colon Cancer

Gas and Bloating Are Normal, But Sometimes They Signal Something Serious

Gas and bloating happen commonly. You can experience these symptoms from swallowing air while chewing gum, or eating artificial sweeteners. Less often, gas and bloating can signal something more serious, such as intestinal disorders like irritable bowel syndrome (IBS) or colon cancer.

Common Causes of Gas and Bloating

There are two main causes of gas: swallowed air and the normal breakdown of undigested food -- especially sugar, starches, and fiber.

Your body expels this gas through burps and farts. Everyone does it. In fact, when your body is healthy, it's normal to pass gas 14 to 23 times a day. 

Bloating can be caused by too much gas in the intestines, although you can also feel bloated and have a normal amount of gas. You can also feel bloated if you have an intestinal disorder, such as irritable bowel syndrome (IBS), which makes you more sensitive to the presence of gas in your intestines.

Gas and Bloating as Symptoms of Cancer

There are times when gas and bloating can signal something more serious: colon cancer. Here's why that can occur.

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 through.

A pattern of gas and bloating may be an indication that a tumor is growing in the colon and possibly 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. This can cause a temporary bowel obstruction.

If your bowel is blocked, air (gas) is trapped and bloating occurs. The trapped air presses on the walls of your colon.

This will likely result in stomach cramping and a noticeable decrease in the number of times you pass gas. Once the blockage clears, all that backlogged air releases in the form of flatulence.

When to Seek 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. When bowel obstructions send you to the emergency room, there's a chance you could get a diagnosis of colon cancer.

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 doesn't help to diagnosis the underlying cause. 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.

Read More: How to Avoid a Delayed Colon Cancer Diagnosis

Other Symptoms of Colon Cancer

In addition to gas and bloating, here are additional signs and symptoms of colon cancer. Note that most people who have gas and bloating (and even other signs and symptoms) don't have colon cancer. 

  • A feeling of needing to have a bowel movement, even if you don't.
  • A change in your bowel movements -- diarrhea or constipation, for example -- that lasts for more than a few days.
  • Blood in the stool.
  • Cramping and belly pain.
  • Unintended weight loss.



"Gas in the Digestive Tract." National Institutes of Health Mar. 2004

"Gastrointestinal Complications." National Cancer Institute 19 Jul. 2006. 

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