What Is A Colon Polyp?

Liver Your doctor may have recently told you that you have a colon polyp. It may have already been removed or destroyed during a colonoscopy. The information below will answer questions you may have about this condition.

What is a colon polyp?
A colon polyp is a benign tumor or growth which arises on the inner surface of the colon. Amazingly, from mouth to rectum, the human intestinal tract averages about 30 feet in length. The last six feet is called the colon, or large intestine. Like a piece of pipe, the colon is hollow and the inner surface is normally smooth. For unknown reasons, some individuals grow polyps, or small lumps of tissue, on the inner wall of the colon. There may be single or multiple polyps. The cause is not known, but the incidence of polyps increases with age.

What is a tumor?
All tissues of the body are made up of millions of tiny individual cells. In health, there is a delicate balance. Old cells are constantly dying and are replaced by new healthy cells. If too many new cells form, they create a lump or mass which is called a tumor. Tumors can be benign or malignant. Benign tumors are not cancer. They can usually be removed and, in most cases, they do not grow back. Cells from benign tumors do not spread to other parts of the body. Most important, benign tumors are rarely a threat to life. Malignant tumors are cancer. Cells in these tumors are abnormal and they continue to divide uncontrollably. Without treatment, they can invade and spread to nearby tissues and organs.

What does a polyp look like?
Colon polyps are found in one of two shapes. Polyps on stems or stalks look like mushrooms and are called pedunculated. When they grow directly onto the inner wall of the colon like spilled paint, they are called sessile and are much more difficult to remove.

Why remove polyps if they are benign?
Colon polyps are important, since some may turn into colon cancer over time. While not every colon polyp turns to cancer, it is felt that almost every colon cancer begins as a small non-cancerous polyp. Fortunately, during colonoscopy. these polyps can be identified and removed or destroyed - thus preventing a possible colon cancer. If a polyp is large enough, tissue can be retrieved and sent for biopsy to determine the exact type of polyp.

What are the types of colon polyps?
There are basically 4 types of polyps that commonly occur within the colon:

    1. Inflammatory - Most often found in patients with ulcerative colitis or Crohn's disease. Often called "pseudopolyps" (false polyps), they are not true polyps, but just a reaction to chronic inflammation of the colon wall. They are not the type that turns to cancer. They are usually biopsied to verify type.

    2. Hyperplastic - A common type of polyp which is usually very small and found in the rectum. They are considered to be low risk for cancer.

    3. Tubular adenoma or adenomatous polyp - This is the most common type of polyp and the one referred to most often when a doctor speaks of colon polyps. About 70% of polyps removed are of this type. Adenomas carry a definite cancer risk which rises as the polyp grows larger. Adenomatous polyps usually cause no symptoms, but if detected early they can be removed during colonoscopy before any cancer cells form. The good news is that polyps grow slowly and may take years to turn into cancer. Patients with a history of adenomatous polyps must be periodically reexamined.

    4. Villous adenoma or tubulovillous adenoma- About 15% of polyps removed are of this type. This is a much more serious type of polyp that has a very high cancer risk as it grows larger. Often they are larger and sessile and not on a stem making removal more difficult. Smaller ones can be removed in piecemeal fashion - sometimes over several colonoscopies. Larger sessile villous adenomas may require surgery for complete removal. Follow up depends on size and completeness of removal.

What is dysplasia?
Dysplasia is halfway between benign and cancer - just like an abnormal Pap smear that isn't cancer yet. When removed and biopsied, both adenomas and villous adenomas may contain abnormal cells that are "almost cancer." Dyplastic polyps can be further divided into low grade dysplasia and the more severe high grade dysplasia. This is a serious finding and may be a marker for malignancy.

What are the stages of colon cancer?
Colon polyps usually cause no symptoms. Without screening and early detection, they may be present silently for many years, slowly growing larger day by day. Eventually, the cells become malignant. This is called adenocarcinoma of the colon or colon cancer. As time goes by, the cancer may spread. Then symptoms become obvious, but it is too late. There are 5 stages of colon cancer, each more serious than the one before:

    Stage 0 - When removed and biopsied, some adenomas or villous adenomas are found to harbor a small focus of actual cancer cells. The cancer is found only on the very surface of the polyp and has not yet invaded into the central core. This earliest stage is also called carcinoma in situ and carries the best prognosis.

    Stage 1 - the cancer is localized to the surface of the colon.

    Stage 2 - the cancer is eating into the wall of the colon.

    Stage 3 - the cancer has eaten through the wall and spread to the lymph glands on the outside of the colon.

    Stage 4 - the cancer has overflowed the lymph glands and spread beyond, usually into the liver.

Can I reduce my risk of colon polyps?
There is no reliable way to prevent further colon polyps. However, the risk of polyps can be lowered somewhat by adding more fiber, extra calcium, and 400 micrograms (mcg.) of the vitamin folic acid to the daily diet. Low dose aspirin may also be protective. One study demonstrated a 40% drop in the incidence of recurrent polyps by taking an 81 mg baby aspirin daily. Interestingly, higher doses were less protective. But since polyps can not be reliably prevented, periodic colonoscopy exams are recommended.

How can I reduce my risk of colon cancer?
The answer is colonoscopy, colonoscopy, colonoscopy... If you are a polyp former, your risk of future polyps is about 60% - and there are no warning symptoms of colon polyps to guide you. The measures described above may be of benefit - but can't reliably prevent future polyps. With periodic colonoscopy exams, you can maximize your chances that any new polyp will be detected and removed before cancer cells develop. Rarely, a colon cancer may develop between colonoscopy exams. Fortunately, they are usually small and curable by surgery. Periodic colonoscopy can significantly reduce your risk of colon cancer.

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