Overview. A colon polyp is a small clump of cells that forms on the lining of the colon. Most colon polyps are harmless. But over time, some colon polyps can develop into colon cancer, which may be fatal when found in its later stages.
Polyps are benign, meaning that they're not cancer and they won't spread, but over time certain types can develop into cancer. One of these types is called adenomatous polyps. These are known as pre-cancerous polyps. Polyps bigger than 1 centimeter have a greater cancer risk than polyps under 1 centimeter.
Polyps are common in American adults, and while many colon polyps are harmless, over time, some polyps could develop into colon cancer. While the majority of colon cancers start as polyps, only 5-10% of all polyps will become cancerous. The size of a polyp typically does make a difference.
The risk of polyps smaller than 5 millimeters (mm) being cancerous is very low. In larger polyps, the risk of cancer increases. Colon polyps grow very slowly and often do not cause symptoms. Regular colon cancer screenings can help detect them before they become cancerous.
Polyps classified as adenomas are considered precancerous and should be removed. Larger polyps have a higher chance of becoming cancer than small polyps. Regular colon cancer screening gives you the best chance of catching adenomas before they become cancerous or catching colon cancer in the earliest stages.
As a general rule, the larger the adenoma, the more likely it is to eventually become a cancer. As a result, large polyps (larger than 5 millimeters, approximately 3/8 inch) are usually removed completely to prevent cancer and for microscopic examination to guide follow-up testing.
These polyps have the potential to become cancer if given enough time to grow. Most of these colon polyps are called adenomas. Serrated polyps may also become cancerous, depending on their size and location in the colon. In general, the larger a polyp, the greater the risk of cancer, especially with neoplastic polyps.
Most polyps are benign (not cancerous). Your doctor can tell if a colon polyp is cancerous during a colonoscopy by collecting tissue to biopsy. The results of the biopsy are typically sent to your doctor within a week. Only 5% to 10% of all polyps become cancerous.
There is no clear-cut definition for “large polyp”. However, polyps > 20 mm should be considered “large”, > 40 mm very large and > 50 mm “giant” (Figures 6 and 7).
Polyps can range in size from the less-than-5-millimeter “diminutive” category to the over-30-millimeter “giants.”
Most polyps grow slowly and take from between 10 and 15 years to become cancerous. Due to this general time frame, most screenings are scheduled every 10 years which gives Colorectal Surgical Associates time to remove any polyps before they become cancerous.
Giant lipomas (>4 cm) are the most common benign tumors in the colon that cause intussusception, although no specific incidence data have been documented. Even patients with large lipomas may have nonspecific or intermittent symptoms, which causes delay and difficulty in making the diagnosis.
The doctor will then send any removed polyps to a pathologist for a biopsy to see if cancer is present. If the biopsy reveals that cancer is present, then cancer specialists will outline a treatment plan for the person. Common treatments for colon cancer include surgery, chemotherapy, and radiotherapy.
Sessile polyps are often precancerous , meaning that cancer can develop in them, but they can also be benign or cancerous. Doctors may find them during a colonoscopy and will often remove them to prevent the risk of cancer developing. Polyps can also be peduncled.
Polyps that are too large or that can't be removed safely during screening are usually removed surgically, which is often performed by inserting an instrument called a laparoscope into the abdomen to remove the diseased portion of the bowel. Colon and rectum removal (total proctocolectomy).
It is considered an abnormal growth, but in many cases, they are found to be benign (commonly in the early stages). However, over time polyps can become large and malignant if they aren't treated. Many polyps are found to be pre-cancerous, which means they have the potential to turn cancerous if they aren't removed.
Depending on their size and location in the colon, serrated polyps may become cancerous. Small, serrated polyps in the lower colon, also known as hyperplastic polyps, are rarely malignant. Larger serrated polyps, which are typically flat (sessile), difficult to detect and located in the upper colon, are precancerous.
Polyps>30 mm in maximum diameter are significantly more advanced histologically but also significantly more difficult to treat successfully than those <30 mm. However, size alone is rarely a contraindication to endoscopic resection.
In 1 to 7 years, depending on a variety of factors: The number, size and type of polyps removed; if you have a history of polyps in previous colonoscopy procedures; if you have certain genetic syndromes; or if you have a family history of colon cancer.
They can occur anywhere in the large intestine or rectum, but are more commonly found in the left colon, sigmoid colon, or rectum.
How long does it take for a polyp to turn into cancer? The growth and mutation of colon polyps into cancer is a slow process, taking an estimated 10 years on average.
Most people with colon polyps have no symptoms and don't know they have them. But if you have symptoms — like rectal bleeding, blood in your stools, or other bowel changes — you should see your provider.
A polyp, which can be flat, raised or on a stalk, is a growth in the large intestine or rectum. You may not have symptoms, so screening is needed to help prevent a polyp turning into colorectal cancer. Screening methods include colonoscopy, sigmoidoscopy, a stool test or a CT scan.
Smoking, obesity, diabetes, and inadequate exercise are risk factors for polyps, but many people with none of these risk factors have precancerous polyps in the colon. There are genetic risk factors for developing polyps as well.
Polyps grow through rapidly dividing cells, which is similar to how cancer cells grow. This is why they can become cancerous, even though most polyps are benign.