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Digestive Health and Wellness

Our Stool Sends Us Signals, and Some May Warn of Colorectal Cancer

Can going to the bathroom be a wellness check? You bet. And when it comes to colorectal cancer, noting the shape and color of your stool can be life-saving. Minnesota woman Anna Dahlgren noticed blood in her stool just once, and it led to the discovery of Stage I colorectal cancer — the earliest and most treatable stage. 

“I knew that blood in stool isn’t normal,” Dahlgren said. “Cancer was the last thing on the list, especially since I didn’t have any family history, and because I was only 33 years old.”

Symptoms of colorectal cancer are numerous, and the most common symptom is none at all. That’s why on-time screening with an appropriate test, as advised by a doctor, is the best way to prevent or detect this disease early. 

But colorectal cancer may affect your restroom habits and the way your stool appears because it develops in the colon or rectum, which comprise the lower end of the digestive system. 

What does healthy stool look like?

Seven common stool shapes are described by the Bristol stool scale. The scale ranges from hard, nut-like shapes that indicate constipation, to a liquid consistency marking severe diarrhea. 

In the middle of the chart lie normal stools, shaped like sausages. Ideally, they are smooth or have surface cracks. Healthy stool should also be any shade of brown or, if you’ve eaten a lot of vegetables lately, a bit green. Any other color should be discussed with a doctor. 

When should I be concerned? 

Blood in stool is a leading symptom associated with colorectal cancer, the second deadliest cancer in the United States among men and women combined. Blood in stool shows up two ways:

If bleeding occurs early in your digestive tract, stool could appear tar-like or brick red. If bleeding occurs lower in the colon or rectum, the stool could appear red. Blood may also appear on the toilet bowl or tissue paper.

Many conditions besides cancer can cause bloody stool, from hemorrhoids to untreated bowel infections. All should be addressed immediately.

“Our study of colorectal cancer patients younger than 50 shows that many who had blood in their stool were first misdiagnosed with hemorrhoids,” said Dr. Laura Porter, Senior Medical Affairs Consultant at the Colorectal Cancer Alliance. “Blood in stool that isn’t rectified with treatment should be an alarm, and patients should seek second opinions. Delays give cancer time to spread.” 

Narrow stools, which may be shaped like a pencil, also provide warning. These happen because a tumor may be blocking easy passage of stool in the lower colon or rectum. A tumor can also cause constipation and diarrhea by causing a partial blockage (constipation) that is then forcefully cleared (diarrhea). 

“Sometimes it can take a painful bowel obstruction for someone to seek attention,” Dr. Porter said. “The problem with waiting for a crisis is that, by then, your tumor may be quite advanced, requiring aggressive treatments that may not work.” 

It’s worth it to plug your nose and take a look at your stool. Other symptoms of colorectal cancer include changing bowel habits, unexplained weight loss, abdominal pain or discomfort, fatigue, and excessive gas.

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