Colon Cancer Stool Symptoms

Over 100,000 people were affected by colon cancer in 2010, according to estimates provided by the National Cancer Institute. This form of cancer affects the colon, the longest region of the large intestine. Colon cancer often results in stool changes in people with this disease. People who develop any of the stool symptoms associated with colon cancer should seek care from a physician as soon as possible.

Toilet bowl in a bathroom (Image: wanrung/iStock/Getty Images)

Loose or Hard Stools

Abnormal cancer cell growth within the colon can disrupt the way in which fluids are absorbed and released within the digestive tract. When the colon does not absorb enough water, people with colon cancer can produce frequently loose, runny stools, a symptom referred to as diarrhea, the NCI explains.

Alternatively, excessive absorption of fluids from the digestive tract can make it difficult for a person to have a normal bowel movement, a symptom called constipation. People with constipation may excrete small, hard masses of stool that are difficult or painful to produce. Chronic bowel movement changes can be signs of alternate medical problems and should be reported to a doctor as soon as possible.

Thin Stools

Colon cancer can cause cancerous tumor growth within the large intestine. These growths narrow the digestive pathway, making it harder for ingested food products to pass through the body. Consequently, people with colon cancer can notice that their stools appear abnormally thin, the American Cancer Society reports. The production of narrow stools may also occur in conjunction with abdominal pain, cramping or gas.

Bloody Stools

Cancer cells can irritate the sensitive lining of the intestinal tract, causing red blood cells to enter the contents of the bowel. Blood within the colon can cause patients with colon cancer to produce bloody stools. The stools can appear abnormally red or dark, or a person may notice blood on the piece of toilet paper used to wipe the rectum after a bowel movement.

Rectal bleeding or blood within the stools can be signs of alternate medical problems, such as a stomach ulcer or inflammatory bowel disease. People who notice blood in their stools should seek prompt care from a doctor.