Colon Polyps and Your Cancer Risk

Table of Contents
View All
Table of Contents

Virtually all colon cancer develops from polyps in the colon. Polyps don't always become cancerous, but your risk of developing cancer increases with the number and size of colon polyps you have. A personal or family history of polyps puts you at higher risk for colon cancer as well.

Polyp Types and Cancer Risk

There are several types of polyps. Two are considered to be very low risk: hyperplastic polyps and pseudopolyps. Hyperplastic polyps are fast-growing, but unlikely to become cancerous. Inflammatory pseudopolyps are a symptom of inflammatory bowel conditions, such as ulcerative colitis or Crohn's disease, and are benign.

Adenomatous polyps, or adenomas, are higher-risk growths. About two-thirds of the polyps found during colonoscopies are adenomas. This type of polyp can take years to grow into cancer, but should still be removed; after 10 years, about 14% may develop into colon cancer. A rare subtype of adenomas, called villous adenomas, are most likely to become cancerous.

Polyp Type Risk for Colon Cancer
Hyperplastic polyps Unlikley
Inflammatory pseudopolyps None (benign)
Adenomatous polyps Higher risk
Villous adenomas Highest risk

The size and number of polyps are also factors in terms of your cancer risk:

  • Approximately 1% of polyps with a diameter less than 1 centimeter (cm) are cancerous.
  • If you have more than one polyp or the polyp is 1 cm or bigger, you're considered at higher risk for colon cancer.
  • Up to 50% of polyps greater than 2 cm (about the diameter of a nickel) are cancerous.

A polyp is considered an advanced colon polyp (a high-risk lesion) if it is 1 cm or larger, has a villous component, or has high-grade dysplasia (highly abnormal cells that could turn into cancer).

Factors That Increase Your Risk

While colon polyps can happen to anyone, there are certain factors that put you at increased risk for them and, in turn, colon cancer. Family history is key among them.

Family history is a key risk factor for polyps and colon cancer. It may not be the most comfortable conversation to have, but you should find out if your parents, siblings, or children have ever had any advanced colon polyps. If they have, you're no longer in the average-risk category for colon cancer.

In general, if any first-degree relatives have had an advanced colon polyp or colorectal cancer, you're considered at higher risk.

Polyps are common and increase with age, which is why colonoscopy is recommend as we grow older.

Other risk factors include:

  • Genetics (some hereditary conditions increase the risk of colon cancer)
  • Race and ethnicity (African Americans and people of Ashkenazi Jewish descent are at greater risk)
  • Obesity
  • Smoking
  • Inflammatory bowel conditions

Screening

Recommendations for screening—most frequently via colonoscopy, though other tests are available—vary based on risk.

For those at average risk, the American College of Gastroenterology (ACG) recommends screening begin at age 45 and continue through at least age 75.

The ACG makes further recommendations based on family history:

  • If two or more first-degree relatives have had advanced colon polyps, begin screening with a colonoscopy at age 40 or 10 years before the youngest affected relative, whichever is earlier.
  • If a parent or sibling has had an advanced polyp, the same higher-risk recommendation applies. For example, if your brother had a polyp removed when he was 45, you should get a colonoscopy when you're 35.

Federal Recommendations for Screening

In 2021, the U.S. Preventive Services Task Force also updated their colon cancer screening guidelines to include a recommendation for routine screening to begin at age 45 for average risk adults. The extended age range is based on the knowledge that regular screening can help catch colon cancer early. Previously, the recommendation focused on people ages 50 and older.

Speak to your doctor about when you should begin screening and how often.

For people without any polyps or family history, colonoscopies are typically recommended every 10 years. If polyps are found during a screening, your doctor may suggest you receive a follow-up colonoscopy earlier than that, depending on your personal risk factors and the type of polyps removed.

If no polyps were found but you have two or more first-degree relatives who had advanced polyps or one first-degree relative with a polyp found at age 60 or younger, your next colonoscopy would typically be five years later.

Prevention

Regular screening is the most important step you can take to prevent polyps and colon cancer.

Getting regular physical activity, not smoking, and moderating alcohol intake will provide protective benefits as well.

Consuming antioxidants in the form of tea, leafy greens, and berries—along with healthy fats and high-fiber grains, fruits, and veggies—may also help.

Lastly, watch your folate, calcium, and vitamin D intake. Maintaining high levels of these nutrients has been linked to reduced risk of colon cancer in some studies.

When to See the Doctor

Polyps are generally asymptomatic. You are unlikely to know you have them, which is why colonoscopies are important. Be sure to stick with your recommended screening schedule.

Polyps can occasionally become ulcerous (turn into a sore) or bleed. Rarely, they can also cause a feeling of incomplete emptying (called tenesmus) or obstruct the bowel, causing constipation, bloating, vomiting, and other concerns.

Such symptoms always warrant checking with your doctor.

A Word From Verywell

While the possibility of having polyps and them turning into cancer is unsettling, know that the majority of polyps can be removed safely during a colonoscopy. Rarely, surgery may be required for larger polyps. Since it's not always possible to distinguish the polyp type during a procedure, doctors will generally remove any polyps they find and send them for biopsy.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Molmenti CL, Kolb JM, Karlitz JJ. Advanced colorectal polyps on colonoscopy: a trigger for earlier screening of family membersAm J Gastroenterol. 2020;115(3):311-314. doi:10.14309/ajg.0000000000000467

  2. American Cancer Society. Understanding your pathology report: colon polyps (sessile or traditional serrated adenomas). Updated February 27, 2017.

  3. Dulskas A, Kuliešius Ž, Samalavičius NE. Laparoscopic colorectal surgery for colorectal polyps: experience of ten years. Acta Med Litu. 2017;24(1):18-24. doi:10.6001/actamedica.v24i1.3459

  4. Summers RM. Polyp size measurement at CT colonography: What do we know and what do we need to knowRadiology. 2010;255(3):707-720. doi:10.1148/radiol.10090877

  5. Shaukat A, Kahi CJ, Burke CA, Rabeneck L, Sauer BG, Rex DK. ACG clinical guidelines: Colorectal cancer screening 2021Am J Gastroenterol. 2021;116(3):458-479. doi:10.14309/ajg.0000000000001122

  6. American Cancer Society. Colorectal cancer risk factors. Updated June 29, 2020.

  7. Davidson KW, Barry MJ, Mangione CM, et al. Screening for colorectal cancer: US Preventive Services Task Force recommendation statement. JAMA. 2021 May 18;325(19):1965-1977. doi: 10.1001/jama.2021.6238.  

  8. Du W, Fang J-Y. Nutrients impact the pathogenesis and development of colorectal cancerGastrointest Tumors. 2015;2(4):203-207. doi:10.1159/000441212

  9. American Society for Gastrointestinal Endoscopy. Understanding polyps and their treatment.