Cancerous polyps tend to grow slowly. It is estimated that the polyp dwell time, the time needed for a small adenoma to transform into a cancer, may be on average 10 years (17). Evidence from the heyday of barium enema examinations indicates that most polyps do not grow or grow very slowly (18).
Adenomas: Many colon polyps are the precancerous type, called adenomas. It can take seven to 10 or more years for an adenoma to evolve into cancer—if it ever does. Overall, only 5% of adenomas progress to cancer, but your individual risk is hard to predict. Doctors remove all the adenomas they find.
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.
If the cancer has not spread and is localized to the colon, then the 5-year survival rate is 91%. However, if the cancer has spread to the nearby tissues or lymph nodes, the 5-year survival rate is 72%. The survival rate drops to 14% if the cancer spreads to distant parts of the body.
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.
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 colon polyps are more likely to become cancerous than others. A doctor who specializes in analyzing tissue samples (pathologist) will examine your polyp tissue under a microscope to determine whether it is potentially cancerous.
It takes approximately 10 years for a small polyp to develop into cancer.
If a cancerous polyp is removed completely during colonoscopy with no cancer cells at the edges of the polyp, then no additional treatment may be needed. If there are cancer cells at the edges of the polyp, additional surgery may be needed.
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.
Approximately 6% of colorectal cancers are diagnosed within 3 to 5 years after the patient received a colonoscopy, according to findings from a recent population-based study.
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'.
In most cases, colon and rectal cancers grow slowly over many years.
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.
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.
Most colorectal cancers start as a growth on the inner lining of the colon or rectum. These growths are called polyps. Some types of polyps can change into cancer over time (usually many years), but not all polyps become cancer. The chance of a polyp turning into cancer depends on the type of polyp it is.
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.
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.
How long does it take a polyp to turn into a cancer? Generally, it's about a 10- to 15-year process, which explains why getting a colonoscopy screening once every 10 years is sufficient for most people. However, this chain of events may occur faster in people with hereditary colorectal cancer syndromes.
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.
Although malignant sessile colon polyps usually require colectomy for proper treatment, the vast majority of malignant pedunculated polyps can be removed colonoscopically for cure.
Villous Adenoma (Tubulovillous Adenoma)
Approximately 15 percent of polyps detected in colon cancer screening are villous or tubulovillous adenomas. This type of polyp carries a high risk of turning cancerous.
Polyps are one of the most common colorectal conditions, occurring in 15 - 20 percent of the adult population. They can occur anywhere in the large intestine or rectum, but are more commonly found in the left colon, sigmoid colon, or rectum.
Larger polyps might be removed during colonoscopy using special tools to remove the polyp and a small amount of the inner lining of the colon in a procedure called an endoscopic mucosal resection. Minimally invasive surgery (laparoscopic surgery).
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.