Polyp Growth Rates 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).
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.
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.
It's estimated that it takes about 10 years for cancer to form into a colorectal polyp.
Doctors generally remove them anyway, just to be safe. 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.
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'.
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.
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 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.
While the majority of colon cancers start as polyps, only 5-10% of all polyps will become cancerous.
Age. Most people with colon polyps are 50 or older.
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.
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.
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 risk of colorectal cancer increases as people get older. Colorectal cancer can occur in young adults and teenagers, but the majority of colorectal cancers occur in people older than 50. For colon cancer, the average age at the time of diagnosis for men is 68 and for women is 72.
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.
; however, despite this effectiveness, it has also become evident that colonoscopy is not perfect and cancers occur after a “clear” colonoscopy at a rate of between 2.5% and 8.7% of the total cancers diagnosed, depending on the method used to calculate and the population.
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.
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.
More than 95% of colon cancer begins with colon polyps. 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.