Colon Cancer Warning Signs & Screening Options - Ascension Wisconsin

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Published on March 20, 2017

Colon Cancer Warning Signs & Screening Options

If you are 50 years or older you need to get tested for colon cancer, earlier if you have symptoms such as rectal bleeding, change in bowel habits, or have a family history of colon cancer. You have the power to PREVENT colon cancer—not just find it early.

Early colorectal cancers usually have no symptoms—making regular screenings essential. However, if you start to experience one of more symptoms, you should talk to your doctor about the screening options available to you.

Signs & Symptoms of Colorectal Cancer

  • A change in bowel habits, such as diarrhea, constipation or narrowing of the stool, that lasts for more than a few days
  • A feeling that you need to have a bowel movement that is not relieved by doing so
  • Rectal bleeding
  • Blood in the stool, which may make it look dark
  • Cramping or abdominal (belly) pain
  • Weakness and fatigue
  • Unintended weight loss

Colorectal cancers can often bleed into the digestive tract. While sometimes the blood can be seen in the stool or make it look darker, often the stool looks normal. But over time, the blood loss can build up and can lead to low red blood cell counts (anemia). Sometimes the first sign of colorectal cancer is a blood test showing a low red blood cell count.

Colon Cancer Screening Options


Sigmoidoscopy is the same as a colonoscopy except only about the first two feet of the colon are examined. Only the lower portion of the bowel needs to cleanse. This is usually completed by taking several enemas prior to the test. Sedation is not usually given for a sigmoidoscopy. If a polyp is found, it is recommended you have a colonoscopy to examine the rest of the colon.

CT Colongraphy

CT Colongraphy (also called a virtual colonoscopy) is when air is used to distend the colon and an X-ray of the abdomen is performed. A 3-D image is created of the colon and rectum and then interpreted by a radiologist to look for polyps and cancer. A bowel prep is required, which is the same medication you would take for a colonoscopy. No sedation is needed.

Stool Sample Testing

  • Option One – Your doctor will give you a home kit to collect a small stool sample. Once collected, the kit needs to be returned to the laboratory. The stool sample is examined for hidden blood, which could indicate a bleeding polyp or cancer. If blood is found, it is recommended you have a colonoscopy to find the reason for the blood.
  • Option Two – This test collects a larger stool sample and is returned to a special laboratory where they check for hidden blood and abnormal DNA markers, which would indicate cancer. If the test is positive, it is recommended you have a colonoscopy.


A colonoscopy is an examination in which a doctor inserts a thin tube with a camera into the rectum and up into the colon (the large intestine). The doctor is looking for small growths, called polyps, which sometimes can become cancerous.

Take Action

Talk to your doctor about which screening option is best for you.

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Colon Cancer Warning Signs & Screening Options