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.
The size of a polyp typically does make a difference. The larger the polyp becomes, the bigger the risk of it developing into colon cancer. That risk increases significantly if the polyp is greater than 10 mm (1 cm); research has shown the larger a colon polyp becomes, the more rapidly it grows.
Polyps are irregular growths in your bowel. Doctors often classify polyps based on size and type to determine their risk of becoming colorectal cancer. Polyps classified as adenomas are considered precancerous and should be removed. Larger polyps have a higher chance of becoming cancer than small polyps.
In general, a rectal or colon polyp is considered complex (also known as “defiant”) if it meets any of the following criteria: Size greater than 2 centimeters. Located in a difficult area or is too flat (sessile) to be removed during a standard colonoscopy.
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.
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.
A polyp can take as many as 10 to 15 years to develop into cancer. With screening, doctors can find and remove polyps before they have the chance to turn into cancer.
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.
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.
Colon polyps are clumps of cells that form in the lining of the colon. They grow slowly over time and typically do not cause symptoms, particularly when they are small.
Most polyps are benign (not cancerous). “However, many polyps are precancerous [adenomas], which, if they remain in place for over 5 to 7 years, may progress towards a cancer,” says Yale Medicine's Harry Aslanian, MD, a Yale Medicine gastroenterologist.
Approximately 1% of polyps with a diameter less than 1 centimeter (cm) are cancerous. More than one polyp or a polyp that is 1 cm or bigger places you at higher risk for colon cancer. Up to 50% of polyps greater than 2 cm (about the diameter of a nickel) are cancerous.
Large polyps are 10 millimeters (mm) or larger in diameter (25 mm equals about 1 inch).
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!
Some types of polyps (called adenomas) have the potential to become cancerous, while others (hyperplastic or inflammatory polyps) have virtually no chance of becoming cancerous. The best course of action when a polyp is found depends upon the number, type, size, and location of the polyp.
After a colonoscopy, eat foods that are soft and easy to digest to ease side effects such as bloating or gas. This may include eggs, white toast, and applesauce for breakfast. For lunch or dinner, choices could include lean chicken without skin, mashed potatoes, and soft-cooked carrots.
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.
A polypectomy lasts about 30 to 60 minutes and is an outpatient procedure, allowing patients to return home the same day. They should be back to a normal routine as soon as the next day.
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.
It takes approximately 10 years for a small polyp to develop into cancer.
This means cancer and polyps can sometimes go undetected. So, despite having had a 'clear' colonoscopy, some patients go onto develop bowel cancer – referred to as post-colonoscopy colorectal cancer (PCCRC) or 'undetected cancer'.
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. Anyone can develop colon polyps.
Most polyps grow slowly and take from between 10 and 15 years to become cancerous.
Results: Mean number of initial polyps were 2.2 and advanced polyps were observed in 40% of the patients. The cumulative recurrence rate of colon polyp was 13.8% within 1 year, and 60% within 3 years, while that of advanced polyps was 2.5% and 31% within 1 and 3 years, respectively.