Are Colorectal Polyps Cancerous?

In this article we will discus colorectal polyps and whether they are cancerous or not. Regular screenings for colon polyps are the best way to prevent polyps from developing into colon cancer. All men and women ages 50 and older should have a fecal blood test every year, a flexible sigmoidoscopy every 5 years, or even both.

What are polyps?

Polyps are abnormal growths that arise from the lining of the large intestine (also called the colon) and protruding into the intestinal canal (lumen). They are one of the most common conditions that affect the colon and rectum, and polyps are found in about nine of every 10,000 persons.

Polyps are usually classified into two types: adenomatous polyps (adenomas) and hyperplastic polyps.

Most polyps are noncancerous and cause no symptoms. They are called hyperplastic polyps.

Adenomas are the precursor lesions for colorectal carcinoma (colon cancer). The more common hyperplastic  polyps are benign and, in most circumstances, are not considered to be pre-malignant.

A colorectal polyp is a growth that sticks out of the lining of the colon or rectum. Polyps are grape-like growths on the lining of the colon and rectum, they can be single or multiple and do become more common in people over age 50. Usually colorectal polyps are benign, but when left untreated, they can in some cases slowly begin develop into cancer, a process that can take years, although the polyps still will not cause any symptoms.   

Colorectal polyps are most of the time benign (meaning that they are not cancerous, not necessarily that they pose no danger at all), but these small growths may cause painless rectal bleeding in some people. Below we will discus types of colorectal polyps that have or don't have the tendency to become cancerous.

Polyps may be (besides age and family history) also associated with some hereditary disorders:

Symptoms of Colorectal Polyps

Colorectal polyps do not cause any symptoms in the majority of cases; however, the following symptoms might occur in some patients:

Are Colorectal Polyps cancerous or not?

Most types of polyps, also called hyperplastic polyps, do not have a tendency to develop into cancer. However, over time, certain types of polyps, also called adenomatous polyps, may develop into cancer. Also, polyps greater than one centimeter in diameter have a greater cancer risk associated with them than polyps sized under one centimeter in diameter. Risk factors for polyps developing into cancer include advancing age (over age 50) or a family history of colon cancer or polyps.

 

Read More: Colorectal (Colon) Cancer: Causes, Symptoms and Treatment

 

Hyperplastic Polyps and Treatment Options

If only hyperplastic polyps are found during your flexible sigmoidoscopy, you usually do not need to have a colonoscopy.
In some cases of very small polyps (5 mm or less) they may not be removed. Namely, some studies have concluded that even if they contain adenomatous tissue, these polyps take so many years to grow that they pose little risk of cancer. This is an exception in people who have inherited polyp syndromes. In their case the polyp will need to be removed.
 

 

Adenomatous polyps (adenomas) of the colon and rectum are benign (non-cancerous) growths that have the potential to develop into colorectal cancer over time, or in other words, they are considered to be pre-malignant. Thus, colorectal adenomatous polyps (adenomas) can develop into cancer and they should be removed. They are larger than one centimeter and are associated with a greater risk of cancer. If they aren't removed, they continue to grow and eventually become cancerous.

 

In most cases, the polyps may be removed at the same time a colonoscopy is performed. In more rare cases, polyps with a high potential of becoming cancerous, a colectomy (removal of a part of the colon) may be recommended.

 

As mentioned previously in this article, the chance of having polyps is increased in patients with a family history of colorectal polyps or colorectal cancer. That also includes familial adenomatous polyposis or inherited disorders such as Gardner’s syndrome. Adenomatous polyps cause few, if any, symptoms of which painless rectal bleeding is the most common.

 

These polyps start out as small nodules on a bowel wall (about the size of a match head) and are almost never malignant at this size, but as they grow they may develop a stalk and look like a small mushroom. In most cases, these adenoma polyps must be removed. 
Most larger polyps are adenomatous, nevertheless this must be determined by tissue examination, also called a biopsy. If during an exam with a flexible sigmoidoscopy adenomatous polyps are found, a colonoscopy is done to look for and remove any polyps in the rest of the colon.

 

Of course only a physician can determine the type of treatment. We will discuss only possible options.

 

Colonoscopy is relatively painless and easy way to remove most polyps. A colonoscopy is an internal examination of the colon and rectum, and is an outpatient procedure that is performed in physician’s office or a surgical suite. Colonoscopy allows the physician to view the polyp(s) in question and remove any that are identified via a biopsy.

 

Complications from colonoscopy are rare, but are possible. There is a slight risk of:

Additional colonoscopies are almost always necessary to monitor healing and ensure that new polyps have not developed. For patients with polyps, follow-up colonoscopy should be performed within 3 to 5 years to see if the polyps have returned.
For larger colon polyps that have a broad area of attachment to the colon wall surgery is needed. These large polyps often cannot be removed safely during a colonoscopy and may be more likely to develop into cancer.

 

Read More: Colon (Colorectal) Cancer: Risks and Prevention Tips

 

In conclusion

Regular screenings for colon polyps are the best way to prevent polyps from developing into colon cancer. All men and women ages 50 and older should have a fecal occult blood test every year, a flexible sigmoidoscopy every 5 years, or both. However, if you have had one or more adenomatous polyps removed, you probably need regular follow-up colonoscopy exams every few years.