Colon Cancer Signs and Symptoms

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Colon cancer is a cancer of the large intestine that makes up a part of the digestive system. Each year a little over 100,000 people in the United States are diagnosed with colon cancer. Colon cancer usually develops from polyps. Polyps are a growth in the colon that can become cancerous. Colon cancer signs and symptoms are usually asymptomatic.

Colon Cancer Signs and Symptoms

Colon cancer signs and symptoms can include the following:

  • Changes in bowel habits. The changes in the bowel habits would last for longer than four days. The specific changes that you can look for include: diarrhea or decreased stool thickness.

  • The presence of blood after a bowel movement. The color of blood would be either bright red or very dark red. The bleeding after a bowel movement could result from an iron deficiency. An iron deficiency can cause fatigue. It is important to note that the appearance of blood in the stool can be a sign that the tumor is bleeding. This can lead to potentially serious complications. Therefore, it is important to visit a doctor and have a fecal occult blood test done.

  • Unexplained weight loss.

  • Prolonged abdominal discomfort.

  • Changes in bowel habits that lead to constipation. Feeling constipated can be a result of a tumor developing in the colon. When this occurs, there is a narrowing in space in the colon for stool to pass.

  • Development of Yellow-green skin color. This is called jaundice.

  • Changes in the appearance of the stool. The presence of thin, pencil like, stool can result from a tumor blocking the stool to pass normally. This can lead to the development of abdominal pain during bowel movements and after bowel movements. As a result, a person can experience multiple bowel movements in a short period of time. When stomach cramps occur, it is a sign that the colon cancer is at an advance stage. There is also a possibility that one can’t pass the stool because of complete blockage. When this occurs, it is likely that the tumor is at the lower end or the rectum.

  • Anemia. Since the right colon is bigger than the left colon, there is a chance that a tumor in the right colon can bleed for many years with no development of symptoms and lead to the onset of anemia.

In summary, the presence of blood, bowel movement changes, and discomfort when passing stool can be a sign of a tumor growing in the colon.


Mayo Clinic. Colon Cancer.