Table of ContentsView AllTable of ContentsAppearanceSymptomsDiagnosisCancer RiskRisk FactorsTreatment
Table of ContentsView All
View All
Table of Contents
Appearance
Symptoms
Diagnosis
Cancer Risk
Risk Factors
Treatment
Asessile polypis a flat, abnormal growth of tissue on the lining of the large intestine, including the largest part called the colon. Most sessile polyps arebenign(non-cancerous) and unlikely to turnmalignant(cancerous).
However, certain changes in sessile polyps may place you at a higher risk of developingcolon cancer. This includes having polyps known assessile serrated adenomasthat areprecancerousand account for 25% of colon cancer cases.
Sessile polyps do not typically cause symptoms and are usually found during a routinecolonoscopy. However, because sessile polyps are relatively flat, they can be harder to detect and remove than other types of polyps.
This photo contains content that some people may find graphic or disturbing.See PhotoJUAN GAERTNER/SCIENCE PHOTO LIBRARY
This photo contains content that some people may find graphic or disturbing.See Photo
This photo contains content that some people may find graphic or disturbing.
JUAN GAERTNER/SCIENCE PHOTO LIBRARY
What Do Sessile Polyps Look Like?
Apolypis an abnormal growth of tissue projecting from themucosal membrane(mucus-producing tissues) of hollow organs.
Sessile colon polyps are usually benign (noncancerous). However, some can change and become precancerous ormalignant.
Symptoms of Sessile Polyps
Sessile polyps, like all polyps in thecolon, usually do not cause any symptoms unless they grow large and undergo certain changes.
It is only when these changes occur that symptoms can develop. This includes bleeding as blood vessels feeding the tumor break and intestinal inflammation and obstruction that can occur as the tumor grows.
Signs that a polyp has turned intocolon cancerinclude:
Diagnosing Sessile Polyps
Sessile polyps are diagnosed during colon cancer screening. Different screening tools can be used, each with different screening schedules:
Colon cancer screening is recommended starting at the age of 45 through age 75. People at high risk, including those with a genetic predisposition or a family history of colon cancer, may need to start earlier.
Signs That a Polyp May Turn Cancerous
While most polyps are benign, the risk of colon cancer can increase based on itsphenotype(observable characteristics) and size. The location of the polyp can also play a part.
The risk of cancer is largely aligned with the type you have. These includeadenomatous polypswhich arise out of glandular tissues.
There are four main types of adenomatous polyps with different potentials for malignancy:
The size of a colon polyp is also indicative of the risk of colon cancer, with larger polyps being at greater risk than smaller ones.
According to a 2020 study inPLoS Computational Biology, the odds of increase in tandem with the size of the polyp in millimeters (mm):
The location of a polyp can also play a role in the colon cancer risk as some are more likely to be hidden than others. This is especially true of sessile polyps that lie flat (as opposed to pedunculated polyps that are raised).
Right-sided polyps (involving theascending colon) are more likely to be cancerous than left-sided polyps (involving thedescending colon). This is because the descending colon is the first section encountered during a colonoscopy; polyps there are easier to spot and remove.
Studies have shown that between 2% and 6% of cancers are missed during a colonoscopy, most often on the right side of the colon. As a result, cancers on the right tend to be more advanced when detected and have a poorerprognosis(outcome) than those on the left.
Another issue is that polyps that develop on the right are more likely to occur in people with a genetic predisposition for cancer, such as those withLynch syndrome. These polyps are also more likely to turn into cancer.
How Long Does It Take for a Sessile Polyp to Become Cancer?
Even so, some cancers are more aggressive, and there have been cases where a sessile serrated polyp has progressed to cancer within five years or less.
Risk Factors for Colon Polyps and Colon Cancer
Polyps can grow anywhere within the large intestine. While there is currently no way to entirely avoid them, there are several factors that may increase the risk of not only colon polyps but also colon cancer.
These include:
How Are Sessile Polyps Treated?
Sessile polyps are usually removed during a colonoscopy. If it cannot be removed and it is relatively small, the provider may mark the polyp with a tattoo and recommend you return for a colonoscopy at a later date.
Even so, the provider will likely take a small tissue biopsy to see if there are any cancer cells. If there is, another colonoscopy would be scheduled to remove the polyp. If it’s not possible to remove it during a colonoscopy, surgery may be needed.
The procedure, called apolypectomy, does not cause any direct pain, although you experience cramping and rectal bleeding for a few days after.
The recommended colonoscopy schedule can differ if polyps are found. For instance:No polyps: Retest in 10 years.One to two polyps less than 10 mm: Retest in seven to 10 years.Three to four polyps under 10mm: Retest in three to five years.More than 10 polyps: Retest every year.
The recommended colonoscopy schedule can differ if polyps are found. For instance:
Summary
Sessile polyps are flat or dome-shaped abnormal growths in the colon’s lining. They are typically asymptomatic and often found during a routine colon cancer screening and may be treated during a colonoscopy.
Colon polyps are usually benign, but all colon cancers begin as polyps. Sessile serrated adenomas are more likely to be precancerous than other types of sessile polyps.
Routine colon cancer screenings should begin at age 45—and younger if you’re at high risk for colon cancer. If you are over 75 and do not have a history of polyps or colon cancer, you may no longer need screening.
14 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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