Colonoscopies play an important role in preventing colorectal cancer by allowing doctors to find and remove precancerous polyps before they become cancerous. If polyps are found during your colonoscopy, your doctor will recommend when you should have your next colonoscopy based on the number, size, and pathology of the polyps.
What are colon polyps?
Colon polyps are abnormal growths that form on the inner lining of the colon (large intestine) and rectum. While most polyps are benign (noncancerous), some types of polyps can eventually develop into colorectal cancer if not removed. The two main types of colon polyps are:
- Adenomatous polyps (adenomas) – Can become cancerous; subtypes include tubular adenoma, tubulovillous adenoma, and villous adenoma
- Hyperplastic polyps – Usually benign; almost never become cancerous
Adenomas are more likely to become cancerous, which is why they are considered precancerous polyps. The larger the adenoma, the greater the risk of it turning cancerous over time. Adenomas with certain cellular characteristics, like villous features or high-grade dysplasia, also have an increased risk of malignancy.
Recommendations for repeat colonoscopy after polyp removal
Medical guidelines provide recommendations for when to repeat colonoscopy surveillance based on polyp findings, with more frequent surveillance for higher-risk individuals. In general:
- If no polyps are found, repeat colonoscopy in 10 years.
- If only 1-2 small (
- If 3-10 adenomas are removed, or at least one is > 1 cm, repeat colonoscopy in 3 years.
- If >10 adenomas are removed or an adenoma shows advanced features (villous components, high-grade dysplasia), repeat colonoscopy in
The timing of repeat exams also depends on other factors like your age, family history, and general health. Your doctor will take all of this into account when determining the appropriate surveillance schedule for you.
1-2 Small Adenomas
If only 1 or 2 small (less than 1 cm) adenomatous polyps are found and removed, guidelines recommend repeating a colonoscopy in 5-10 years. The risks of advanced neoplasia developing in the next 5-10 years is low if no more than two small adenomas were found. A 5-10 year interval provides enough time to find and remove any new polyps before they have a chance to turn cancerous.
Finding 3-10 adenomas during colonoscopy indicates an increased risk for developing future polyps. In this case, guidelines recommend repeating the colonoscopy in about 3 years. The more polyps found, the higher the chances some were missed and the faster additional polyps will grow. Following up in 3 years balances the risks and benefits of repeat screening.
More Than 10 Adenomas
When more than 10 adenomas are removed from a single colonoscopy, it suggests the colonic mucosa may have a high propensity for growing new polyps quickly. Individuals who have had more than 10 adenomas removed are encouraged to repeat colonoscopy in less than 3 years. Some may need another colonoscopy as soon as within 6-12 months to check for new polyp growth.
Large Adenoma (> 1 cm)
Larger adenomas (greater than 1 cm) have a higher chance of harboring advanced features like villous components or high-grade dysplasia. There is also an increased possibility that cancer cells are already present. The recommendation is to repeat colonoscopy within 3 years when one or more large adenomas are found.
Advanced Adenoma Features
Adenomas with villous features, high-grade dysplasia, or invasive cancer are considered advanced adenomas. They have the highest risk of progressing to colon cancer. If an advanced adenoma is identified, guidelines recommend repeating colonoscopy within less than 3 years. Depending on the level of concern, your doctor may recommend a repeat exam even sooner.
What if polyps cannot be completely removed?
Sometimes polyps are difficult to remove completely during colonoscopy due to their size, shape, or location. When a polyp is biopsied but not entirely removed, this is called a residual polyp. In cases of residual polyps, an earlier follow-up colonoscopy is recommended, usually within 2-6 months, to try to completely remove the remaining polyp tissue.
Surveillance recommendations for different polyp scenarios:
|Polyp Finding||When to Repeat Colonoscopy|
|No polyps||In 10 years|
|1-2 small (||In 5-10 years|
|3-10 tubular adenomas||In 3 years|
|> 10 adenomas||In|
|Large adenoma (> 1 cm)||In 3 years|
|Adenoma with advanced features||In|
|Residual polyp (not completely removed)||In 2-6 months|
What affects the colonoscopy timeframe?
While the guidelines provide recommended intervals based mainly on polyp characteristics, other factors also influence the timing of repeat colonoscopy, including:
- Age – More frequent screening is recommended starting at age 50, or earlier with family history.
- Number and size of polyps – More polyps and larger polyps increase risk and warrant earlier repeat exams.
- Polyps with advanced features – Villous components, high-grade dysplasia, or cancerous cells call for follow-up within 3 years.
- Family history – Increased colon cancer risk may necessitate more frequent screening.
- Previous colonoscopy findings – Discovery of dysplasia or cancer may shorten recommended intervals.
- Quality of prep and exam – Poor prep or inability to fully visualize colon may mean rescreening sooner.
- Other health conditions – Diseases like inflammatory bowel disease impact screening strategy.
Your doctor will take all these factors into account when deciding the right colonoscopy timeline for your individual screening needs.
Can lifestyle changes reduce colonoscopy frequency?
Adopting certain lifestyle changes may allow for less frequent colonoscopy screenings. Recommendations that may help lower colorectal cancer risk include:
- Eating more fruits, vegetables, and whole grains.
- Limiting red and processed meats.
- Maintaining a healthy weight.
- Exercising regularly.
- Quitting smoking.
- Limiting alcohol.
- Taking aspirin or other NSAIDs.
While these healthy lifestyle choices may moderately reduce your overall colon cancer risk, they are not enough to justify delaying colonoscopies beyond recommended intervals after polyp removal. Screening colonoscopies remain essential for polyp surveillance.
Can too frequent colonoscopy be harmful?
There are some risks associated with colonoscopy screening, so too frequent colonoscopies may cause more harm than benefit in certain situations. Potential harms of overscreening may include:
- Unnecessary procedures if no new polyps are found
- Higher chance of complications like bleeding or bowel tears
- Increased costs for repeated procedures
- Burden of frequent bowel preps
- Missed work and disruption of daily activities
These potential downsides need to be weighed against the benefits of detecting worrisome polyps early. Your doctor can help find the right balance based on your polyp history and overall risk.
When can colonoscopy be stopped?
At a certain age, your doctor may recommend discontinuing colonoscopy screening if:
- You have little to no risk for colorectal cancer based on polyp findings and family history.
- You have serious health conditions that make colonoscopy very high-risk.
- Your life expectancy is limited such that screening is unlikely to provide benefit.
On average, guidelines recommend discontinuing colonoscopy screening around 75-85 years old for average-risk individuals with normal prior colonoscopies. However, the decision to stop screening is made on a case-by-case basis depending on your polyp history, overall health status, and estimated remaining life expectancy.
Colonoscopy intervals after polypectomy depend mainly on the number, size, and characteristics of polyps found. In general, guidelines recommend:
- 10 years if no polyps.
- 5-10 years if 1-2 small adenomas.
- 3 years if multiple or large adenomas.
- 10 total adenomas.
Your screening schedule also takes into account your age, family history, health conditions, and colonoscopy findings. While some lifestyle changes may lower colon cancer risk a bit, they do not negate the need for surveillance colonoscopies at guideline-recommended intervals after polyp detection. With customized screening, colonoscopies can provide important polyp surveillance without overscreening.