As often as 40% of the time, a precancerous polyp — frequently a type called an adenoma — is found during a screening colonoscopy. Colon cancer is found during only in about 40 out of 10,000 screening colonoscopies, Dr. Sand said.
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 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.
Colon polyps are extremely common among adults 50 years of age and older, occurring in over 40 percent of individuals who undergo screening colonoscopy.
A polyp is a small growth of excess tissue that often grows on the lining of the large intestine, also known as the colon. Colon and rectal polyps occur in about 25 percent of men and women ages 45 and older.
He says you might be surprised how often colonoscopies uncover polyps lurking in your colon. "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.
Aging — Polyps and colorectal cancers are uncommon before age 40. Ninety percent of cases occur after age 50, with males somewhat more likely to develop polyps than females; therefore, colon cancer screening is usually recommended starting at age 50 for both sexes.
Anyone can develop colon polyps. You're at higher risk if you are 50 or older, are overweight or are a smoker. You're also at higher risk if you have a personal or family history of colon polyps or colon cancer.
Colon polyps are common in American adults. Anywhere between 15 and 40 percent of adults may have colon polyps. Colon polyps are more common in men and older adults.
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.
Colonoscopic polypectomy is the best diagnostic and therapeutic tool to detect and prevent colorectal neoplasms. However, previous studies have reported that 17% to 28% of colorectal polyps are missed during colonoscopy.
But some colon cancers may start as polyps. So, the more polyps you have, the higher your cancer risk. Someone with just one or two small polyps is generally at lower risk of having or developing colon cancer than someone with three to nine, or more.
Symptoms of bowel polyps
But some larger polyps can cause: a small amount of slime (mucus) or blood in your poo (rectal bleeding) diarrhoea or constipation. pain in your tummy (abdominal pain)
Polyps of the colon and rectum are most often benign. This means they are not a cancer. You may have one or many polyps. They become more common with age.
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.
Anyone can develop colon polyps, and about 6% of children have them. However, the risk of colon polyps and colon cancer increases with age. About a third of people over 50 have polyps. More than 95% of colon cancer begins with colon polyps.
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.
Most colorectal cancers start as colon polyps, abnormal growths in the wall of the colon. Some polyps can develop into cancer if left untreated for a long time (usually at least 10 years). Screening is crucial for cancer detection because most colorectal cancers don't cause symptoms in the early stages.
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.
Colon polyp development involves genetic and epigenetic changes and environmental effectors such as stress in this process can drive the normal colonic epithelial cells to hyperplastic and adenomas [25-27].
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.
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).
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.
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.