There are two main categories of polyps, nonneoplastic and neoplastic. Nonneoplastic polyps typically do not become cancerous. Neoplastic polyps include adenomas and serrated types. Adenomas are the most likely to turn into cancer if given enough time to grow.
In multivariable analysis, the presence of 5 or more polyps at index colonoscopy was found to be associated with the risk of metachronous HR-CRN (OR, 2.575, p = 0.049) after adjusting for risk factors, such as obesity, diabetes, and smoking.
It is well known that colorectal cancers arise from adenomatous polyps, which have three histologic variants: tubular, tubulovillous, and villous adenomas. Tubular adenomas represent ~75% to 85% of adenomatous polyps and have < 5% chance of harboring a malignancy.
Hyperplastic polyps — Hyperplastic polyps are usually small, located in the end-portion of the colon (the rectum and sigmoid colon), have no potential to become malignant, and are not worrisome (figure 1).
villous polyps — aggressive and more likely to turn into cancer; should be removed completely when found; require a colonoscopy one year after they are removed, and then every one to three years after that; occasionally so large that they must be removed with surgery.
A polyp is a growth inside of your body. Most aren't cancerous (benign), but a polyp contains abnormal cells or cells that may become abnormal (malignant). A polyp is usually a flat bump or shaped like a mushroom. Cancerous polyps can develop in many places in your body, such as your colon or uterus.
The most common malignant polyps contain cancer cell type called adenocarcinoma.
Larger polyps, however, pose a greater threat. Pickhardt et al. found that that cancer incidence increased with polyp size — 91 percent of all advanced adenomas and 100 percent of cancer cases were from individuals with lesions of 10 mm or larger.
If the colonoscopy finds one or two small polyps (5 mm in diameter or smaller), you are considered at relatively low risk. Most people will not have to return for a follow-up colonoscopy for at least five years, and possibly longer.
Research indicates that as many as 60 percent of polyps may grow back within three years. Also, about 30 percent of patients who've had polyps removed will develop new ones. This is why it is important to talk to the care team about follow-up screening within five years after the polyps are removed.
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.
If your doctor finds precancerous polyps, there is no need for any additional treatment as long as they remove the entire polyp. Removing the tissue stops the development of cancer.
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.
Colon cancer, or cancer that begins in the lower part of the digestive tract, usually forms from a collection of benign (noncancerous) cells called an adenomatous polyp. Most of these polyps will not become malignant (cancerous), but some can slowly turn into cancer over the course of about 10-15 years.
"Precancerous polyps are extremely common," he says. "We expect to find them in more than a quarter of the colonoscopies that we do at a minimum. So, you know, maybe a third or even a half of all patients getting [a] colonoscopy will have precancerous polyps."
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.
The only way to be sure that a colon polyp has cancer is to remove the polyp and look at it under a microscope. But a colonoscopy may show some signs that there may be cancer.
The three different polyps are villous, tubular and tubulovillous. Adenomatous polyps will gradually show dysplastic changes, which differentiates them from hyperplastic polyps. In general, colonic polyps are benign but those that develop high-grade dysplasia will become malignant with time.
These features include the size, the presence of depressed ulceration, irregular contours, deformity, a short and immobile stalk and the inability to elevate a sessile polyp when a submucosal bleb is formed.
If a polyp has cancerous cells, they will also biopsy nearby lymph nodes to determine if the cancer has spread or metastasized to other areas of the body. In this case radiation, chemotherapy or other therapies may be recommended. Colonoscopy screenings can be life saving!
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.
They look like bumps growing from the inside lining of the bowel protruding out. They sometimes grow on a “stalk” and look like mushrooms. Some polyps can be flat. People can have several polyps scattered in different parts of the colon.