Colonoscopies are common screening procedures used to examine the large intestine. This article clarifies what colon polyps are and provides insight into the typical number of polyps found during a screening colonoscopy.
Understanding Colon Polyps
Colon polyps are growths that form on the inner lining of the large intestine. They appear as small clumps of cells. While most polyps are not cancerous, some types can develop into colorectal cancer over time if not removed.
Polyps are classified as either neoplastic or non-neoplastic based on their potential for cancer development. Neoplastic polyps, such as adenomas and sessile serrated lesions, can grow into cancer. Adenomas are the most common type of neoplastic polyp and are considered precancerous. Non-neoplastic polyps, like most hyperplastic polyps, typically do not become cancerous. Because almost all colorectal cancers begin as a polyp, their removal during a colonoscopy is a key preventive measure.
The Average Number of Polyps Found
The number of polyps found during a screening colonoscopy can vary widely. It is common for people to have anywhere from no polyps to a few. One study indicated that the mean number of endoscopically detected polyps per procedure was approximately 1.5. Many people undergoing a colonoscopy will have zero polyps.
While the number of polyps is noted, their type and size are often more significant in determining potential risk and subsequent care. For instance, five benign polyps may be less concerning than two higher-risk polyps, such as adenomas with dysplasia. Polyps larger than 10 millimeters or those with specific characteristics like villous features or severe dysplasia are considered advanced lesions and carry a higher risk. The goal of a screening colonoscopy is to detect and remove polyps before they become cancerous.
Factors Influencing Polyp Count
Several factors can influence an individual’s likelihood of developing colon polyps and the number found during a colonoscopy. Advancing age is a factor, with polyps becoming more common as people get older. Approximately 40% of individuals over the age of 50 have precancerous polyps.
A personal or family history of colon polyps or colorectal cancer also increases the risk of developing polyps. Certain inherited genetic conditions, such as Familial Adenomatous Polyposis (FAP) or Lynch syndrome, significantly elevate polyp risk, sometimes leading to hundreds or thousands of polyps. Lifestyle choices play a role, including:
A high-fat, low-fiber diet
Obesity
Physical inactivity
Smoking
Heavy alcohol consumption
Inflammatory bowel diseases, such as ulcerative colitis or Crohn’s disease, can also increase the risk of polyp formation.
After Polyp Removal
Once polyps are found and removed during a colonoscopy, they are sent to a laboratory for detailed examination by a pathologist. This pathology analysis determines the specific type of polyp and whether it shows any signs of dysplasia, which refers to abnormal cell changes. Understanding the polyp’s characteristics is essential for guiding future medical recommendations.
The pathology results, including the polyp’s type, size, and number, inform the schedule for subsequent colonoscopies, known as surveillance. For instance, if one or two small adenomas were removed, a follow-up might be recommended in 7 to 10 years. If three to four adenomas were found, a repeat colonoscopy might be advised in 3 to 5 years. Finding five to ten adenomas typically leads to a recommendation for a three-year follow-up. The presence of certain types, like sessile serrated polyps, or polyps larger than 10 millimeters, can also necessitate earlier follow-up examinations. Adhering to these surveillance schedules is important for preventing colorectal cancer.