Colorectal polyp

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at May 7, 2016
StartDiseasesColorectal polyp

Among cancers that affect both men and women, colon cancer is the second most common type of cancer and is responsible for more cancer deaths each year than any other type of cancer. While not all polyps become cancerous, colon cancer almost always begins as a benign colorectal polyp (also referred to as a colon polyp or colonic polyps) that becomes cancerous over time if left untreated.

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Definition & Facts

A polyp is simply a small group of cells that has formed together in the colon to create a mass. They occur when the cells in the intestinal wall undergo changes, but doctors are not sure what causes the cells to change and mutate. These cell mutations essentially prevent the cells from aging, allowing them to accumulate in the body rather than dying as they normally would when new cells become ready to take their place.

Colon polyps can form anywhere on the large intestine and, if large enough, interfere with the digestive process. According to the Centers for Disease Control and Prevention, up to 60% of colon cancers could be avoided with proper screening and treatment. The five-year survival rate for those who have cancerous polyps that were detected early and treated is an encouraging 90%, proving that colorectal polyps and cancers are very treatable.

Symptoms & Complaints

Many people with small polyps don't experience any symptoms at all and discover the condition only through preventive screening. Symptoms are more likely with large polyps but still may not be present. When they occur, symptoms may include bloody stool, black stool, anal bleeding, pain, and vomiting.

Some people experience abdominal pain and cramping that refuses to ease or go away. Polyps can cause anemia over time as slow bleeding from them may deplete the body's iron supply. This can cause fatigue and lead to a constant feeling of exhaustion. Constipation and diarrhea can both be signs of polyps as well but only if they last longer than a week.

Causes

It is unclear what causes colorectal polyps, but there are some conditions that increase their risk. Polyps occur most often in those over 50. They are more likely to occur in those who have had polyps in the past and those with a family history of intestinal polyps or colon cancer. Inflammatory bowel diseases such as Crohn's disease and ulcerative colitis also increase the risk of polyps, as does having uncontrolled or poorly controlled type 2 diabetes.

Women diagnosed with ovarian cancer or uterine cancer before age 50 are at an increased risk of polyps as are African-Americans. It is unclear why African-Americans are more susceptible to colon polyps but the condition affects this population at a much higher rate than any other United States demographic. Obesity, tobacco use, and alcohol consumption may also contribute to polyps.

Diagnosis & Tests

The most common test performed to look for and diagnose polyps is a colonoscopy. During this procedure, a small tube and camera are placed in the rectum and used to examine the large intestine. If polyps are found, they may be removed during the procedure and biopsies or tissue samples may be taken to test for colon cancer.

A sigmoidoscopy is also an option, allowing doctors to use a light tube to view the colon. This procedure uses a smaller tube but does not allow the doctor to remove the polyp immediately. A colonoscopy is still needed to remove the polyps.

Less frequently doctors use barium enemas or virtual colonoscopy to diagnose polyps. These procedures use diagnostic scans and X-rays to look for polyps. Doctors sometimes collect stool samples from patients and perform tests capable of detecting microscopic amounts of blood. If blood is found, further testing will be conducted to look for polyps. Most of these tests are covered by insurance companies as a preventive measure.

Treatment & Therapy

There are no medications that will remove or shrink polyps once they have formed. Instead, colorectal polyps are typically removed manually and immediately if found during a colonoscopy. This procedure is performed simply and quickly with no need for additional treatment. A colonoscopy will be scheduled to remove polyps if they are found during a sigmoidoscopy or other diagnostic procedure.

In some cases, large polyps must be removed via laparoscopic surgery. In this minimally invasive procedure, the doctor removes the polyp through several small openings made in the abdomen. In rare cases, the colon and rectum are removed but this is uncommon.

Once a polyp has been removed, treatment is concluded with the exception of follow-up colonoscopies to ensure that new polyps have not formed. These are typically scheduled as follows but may be done more or less often depending on individual circumstances:

  • In 10 years after a clean colonoscopy
  • In 5 years after removal of up to two small polyps
  • In 3 years if there were more than two small polyps or a large polyp
  • In 6 months if very large polyps were present or had to be removed in sections

Prevention & Prophylaxis

Because doctors are unsure what causes polyps to form, preventing them completely may not be possible. Polyps tend to form very slowly, making it difficult to study their prevention in a controlled environment. A diet rich in vegetables, fruits and whole grains may be beneficial to preventing polyps, however, especially when paired with regular exercise and an active lifestyle. Colorectal polyps are less likely in those who maintain a healthy weight, limit alcohol consumption and avoid tobacco.

Calcium supplements have been show to reduce the formation of polyps. Daily aspirin intake can have unwanted side effects, so it is best to discuss the risks and benefits of an aspirin regimen with a physician before beginning. Genetic testing is able to uncover certain genetic predispositions for polyps but is not able to screen for all of them. This type of testing is generally worthwhile only in those with a family history of colorectal polyps.