Colon cancer symptoms may include changes in bowel movements or stool shape. However, there is no specific colon cancer stool shape. Regular screenings are the best way to identify signs of colon cancer early.

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Colon cancer begins in the colon but can spread to other body parts. Symptoms vary between individuals, though some people may not experience any symptoms.

This article will review common symptoms of colon cancer. It will also discuss the disease’s complications, diagnosis, stages, and outlook.

Some people with colon cancer may pass more narrow stools than usual. In some instances, this could indicate a blockage within the colon. For example, a tumor in the colon could restrict the space a stool has to pass through.

However, narrow stools can occur for various reasons, which are not a sure sign of colon cancer. People with colon cancer often experience bowel movement changes, but no single stool shape indicates this disease.

The symptoms of colon cancer depend on the individual and the disease stage. Some people may experience symptoms, while others may experience few symptoms, if any.

The more common symptoms of colon cancer may include the following:

Symptoms of advanced colon cancer

In advanced cases of colon cancer, tumors may spread to other parts of the body. Colon cancer may cause symptoms, such as jaundice or abdominal pain, if it has spread to the liver. If it has spread to the lungs, colon cancer could also cause a cough and trouble breathing.

However, many of these abdominal or gastrointestinal signs and symptoms can also indicate other conditions, such as certain infections, irritable bowel syndrome, or inflammatory bowel disease.

Individuals experiencing gastrointestinal symptoms or changes to their bowels should speak with a medical professional to determine the cause.

The most common colon cancer complications include obstruction, perforation, and bleeding. Tumors growing within the colon can block or obstruct the bowels. They can also tear or perforate affected parts of the colon.

As many as 50% of people with colon cancer also report bleeding. However, although this is a common complication, it is not typically a serious concern.

There are many tests within the colon cancer diagnostic process. A doctor may first perform a physical exam and review an individual’s family and medical history. They may also ask individuals to bring in a stool sample for analysis.

After an initial exam, blood tests can help screen for signs of colon cancer. These tests may indicate the presence or spread of colon tumors.

A medical professional will perform a colonoscopy to confirm a colon cancer diagnosis. If a colonoscopy reveals areas of suspected cancer, a doctor can send small samples of these areas to the lab for further testing. Lab and imaging tests can confirm the presence and stage of the disease.

Colon cancer stages

Colon cancer staging indicates how much the disease has grown and spread. Staging for colon cancer typically involves:

  • Stage 0: Atypical cells appear on the inner wall of the colon.
  • Stage 1: The cancer has grown on the inner colon wall and spread to nearby tissue layers.
  • Stage 2: The cancer has spread to other parts of the colon or nearby organs.
  • Stage 3: The cancer has spread through the colon and may have reached several lymph nodes.
  • Stage 4: The cancer has spread to distant organs or lymph nodes.

Individuals who receive a colon cancer diagnosis in the early stages have a higher likelihood of fully recovering.

About 90% of people who receive an early diagnosis of colon cancer will survive for at least 5 years. That number drops to about 14% for individuals whose colon cancer has spread beyond the regional area of the colon. The overall 5-year survival rate for colon cancer is 64% for all stages combined.

The risk of cancer returning decreases significantly after an individual has been symptom-free for 5 years. However, it is still possible for the disease to recur after this period.

The best way to reduce the risk of colon cancer is to get regular screenings. The Centers for Disease Control and Prevention (CDC) recommend screening for adults between 45 and 75 years old. A person can speak with a doctor to learn more about how to get screened and how often screenings are necessary.

The symptoms of colon cancer may affect bowel movements and stool. However, colon cancer does not typically affect stool shape — no specific stool shape indicates colon cancer.

Some people with colon cancer may not experience any symptoms of this disease. Getting regular screenings for colon cancer is the best way to find the condition early. An early colon cancer diagnosis dramatically increases the likelihood of responding fully to treatment.

Individuals with concerns about bowel changes or other potential symptoms should consult a doctor. Only a healthcare professional can help determine the cause of these symptoms.