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.
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).
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.
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.
The polyp can enlarge, as mutated cells start growing faster and living longer. Eventually, in this all this activity, it's possible that a mutation takes a cancerous turn. Thankfully, this is a slow-moving process — and that gives you the chance to stay a step ahead of colorectal cancer.
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!
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'.
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.
Colon cancer is typically slow-growing, starting as a benign polyp that eventually becomes malignant. This process may occur over many years without producing any symptoms. Once colon cancer has developed, it may still be years before it is detected.
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.
Not all polyps will turn into cancer, and it may take many years for a polyp to become cancerous. Anyone can develop colon and rectal polyps, but people with the following risk factors are more likely to do so: Age 45 years and older. A family history of polyps or colon cancer.
If your doctor finds one or two polyps less than 0.4 inch (1 centimeter) in diameter, he or she may recommend a repeat colonoscopy in 7 to 10 years, depending on your other risk factors for colon cancer. Your doctor will recommend another colonoscopy sooner if you have: More than two polyps.
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. Colon cancer can be fatal when found in its later stages.
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.
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.
Once a colorectal polyp is completely removed, it rarely comes back. However, at least 30% of patients will develop new polyps after removal. For this reason, your physician will advise follow-up testing to look for new polyps. This is usually done 3 to 5 years after polyp removal.
A gastroenterologist, the specialist who usually performs a colonoscopy, can't tell for certain if a colon polyp is precancerous or cancerous until it's removed and examined under a microscope.
Figure 1 shows the cumulative incidence of colorectal cancer starting 1 year after a negative colonoscopy: 0.4% at 3 years, 0.8% at 5 years and 2.3% at 10 years. The overall incidence rate of colorectal cancer was 1.8/1,000 person-years in the study cohort.
If a polyp is removed or a sample of the colon lining is removed (a colonic biopsy), it may take a few days (or more) to find out that cancer, an adenoma or another finding was discovered.
If a polyp is not completely removed by colonoscopy or surgery, and the biopsy results are completely benign, another colonoscopy should be done in 3-6 months. Every effort should be made to remove polyps, as there is a significant risk that over time they can progress to an invasive cancer.
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.
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 larger the polyp becomes, the bigger the risk of it developing into colon cancer.
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.