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Screening for Colorectal Cancer


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Screening for colorectal cancer means looking for signs of cancer in your large intestine before you have symptoms.

Screening can help find cancer at an early stage. This can make treating it easier because the cancer might not have spread.

Screening for colorectal cancer is recommended for everyone beginning at age fifty.

You may need screening earlier and more often if you or your family has a history of colorectal cancer or diseases that inflame your bowel.

Some tests screen for colorectal cancer by looking inside your large intestine. These tests include sigmoidoscopy, colonoscopy, and colonography.

A sigmoidoscopy views the lower third of your large intestine using a camera on the end of a flexible tube.

The tube is inserted through your anus into your large intestine to look for polyps and other signs of cancer.

A colonoscopy also views your large intestine using a similar camera.

But, it looks along the entire length of your large intestine for polyps or other signs of cancer.

A colonography, also known as “virtual colonoscopy,” uses CT scans of your large intestine.

A computer uses the scans to make a three dimensional view inside your large intestine to look for signs of cancer.

Other tests screen for colorectal cancer by looking at your stools, or feces.

Fecal blood tests look for traces of blood in stool samples.

These tests are often are often done in combination with a sigmoidoscopy.

Blood in your stool may be a sign of polyps in your colon, or cancer.

However, stool blood may have other causes that aren’t cancer. Talk to your healthcare provider about what your test results mean.

In a stool DNA test, a stool sample is checked for abnormal DNA from polyps or cancer.

If you have questions about these tests or your test results, talk to your doctor.