More About Polyps
What causes a polyp to form?
The exact causes of polyps are uncertain, but they appear to be caused by both inherited and lifestyle factors. Genetic factors may determine a person's susceptibility to the disease, whereas dietary and other lifestyle factors may determine which individuals at risk actually go on to form polyps (and later cancers). Diets high in fat and low in fruits and vegetables may increase the risk of polyps. Cigarette smoking, a sedentary lifestyle and obesity may also increase the risk.
How can you prevent polyps from forming?
Few studies have been able to show that modifying lifestyle can greatly reduce the risk of colon polyps or cancer. However, reducing dietary fat, increasing fiber, ensuring adequate vitamin and micro-nutrient intake and exercise may improve general health. Studies have shown that getting adequate calcium may reduce the risk of polyps.
If the polyp is removed, does that mean I am cured?
Removal of a benign polyp does prevent a cancer from developing at that one location, but the patient is at risk to develop polyps at other locations. Close follow-up, often with repeated colonoscopies at set intervals, is needed for these patients. If you have had a polyp removed in the past and change doctors, make sure that your new doctor knows about the polyp history, including pathology results. You may need a different schedule or frequency of colonoscopies than patients who have never had polyps removed during previous colonoscopies.
Can polyps "fall off" or take care of themselves without having them removed?
Polyps have a slow growth rate, and studies show polyps that are 10 millimeters or less have a fairly stable size over a three-year period. A true polyp will never "fall off" or take care of itself on its own. The risk of leaving a polyp in place or failing to get the appropriate follow-up colonoscopies is that the polyp could become cancerous.
Is it possible to have colon or rectal cancer without having polyps?
Colorectal cancer can occur without polyps, but it is thought to be an uncommon event. Individuals with long-standing inflammatory bowel diseases, such as chronic ulcerative colitis and Crohn's colitis, are at increased risk for developing colorectal cancer that occurs in the absence of obvious polyps.
However, colorectal cancer associated with inflammatory bowel disease accounts for less than one percent of all colorectal cancers diagnosed in the United States each year.
There are also reports that suggest some tiny colon cancers may arise in flat colon tissue that is either entirely normal or contains a small flat area of adenomatous (precancerous) tissue. This type of colon cancer is the exception to the rule, and it may be that a small polyp or abnormal growth preceded the cancer and was too small to see. The vast majority of colorectal cancers arise from pre-existing adenomatous (precancerous) polyps.
Do all polyps turn into colon cancer?
Polyps can be classified as pre-cancerous or not pre-cancerous based on the types of cells they are made of. Once a polyp is removed during colonoscopy, it is sent to a pathologist to review the polyp under a microscope to see if it is pre-cancerous or not. Generally speaking, there are two types of benign polyps: adenomas and hyperplastic polyps. Adenomatous polyps are made up of pre-cancerous cells. These types of polyps have the potential to turn into cancer over years. Hyperplastic polyps are benign polyps that do not turn into cancer. It is important to complete your screening colonoscopy and to make sure to follow through with your doctor’s recommendation for follow-up colonoscopies so that these pre-cancerous polyps can be removed.