Colonoscopy Screening Guidelines: Who is Eligible, How Often, What Characteristics Make You Prone

Colonoscopy Screening Guidelines

According to the American College of  Gastroenterology, a colonoscopy is the most frequently performed gastrointestinal procedure in the United States.  Many healthcare professionals consider a colonoscopy the most effective method for detecting and preventing colon cancer for the following reasons:

Early detection. A colonoscopy detects colorectal cancer at its earliest and most treatable stage.

Polyp removal. During the procedure, polyps (abnormal tissue growths that may develop into cancerous tissue) are easily visualized and removed immediately.

Reduced mortality and incidence rates. There has been a significant reduction in the incidence and deaths from colon cancer because of colonoscopy screening. Observational studies have shown a 31%-71 % reduction in colorectal cancer incidence and 65%-88% reduction in mortality to be associated with screening colonoscopies. 

Colonoscopy Procedure Quick Summary

A colonoscopy is considered a 1-step or direct test because it is both diagnostic and therapeutic. The procedure involves using a flexible tube equipped with a camera that can both visualize and treat lesions found during the colorectal exploration. The majority of colorectal cancers develop from adenomas, abnormal precancerous lesions found in the intestinal lining of the colon and rectum. These lesions can be removed during a routine colonoscopy and stop the progression of the adenomas developing into cancer. 

In this article, you will read about the guidelines for who is recommended for a colonoscopy, the risk factors that increase your need for a screening colonoscopy, and how often different populations need to get screened. 

Who is Eligible / Recommended For a Colonoscopy

Historically, Americans at average risk between the ages of 50 and 75 are recommended to have a colonoscopy.  Recently, however, there has been a rising incidence (51%) of colorectal cancer in people younger than 50 years of age in the United States. The American Cancer Society published new guidelines in 2018 that presented a recommendation to lower the starting age for screening from 50 to 45. 

This updated recommendation typically pertains to people who are considered at an increased or high risk for developing colorectal cancer. There are many colorectal cancer screening methods available for you to choose from if you are approaching the age for screening. These include an at home screening stool based kit that detects blood caused by a polyp or adenoma. However, if you have certain risk factors your physician will typically advise you to get a colonoscopy instead of an at home colon screening.

The following risk factors typically make you eligible for a colonoscopy prior to turning 50:

• Family history of colorectal cancer
• Personal history of colorectal cancer or polyps
• Personal history of inflammatory bowel disease, including ulcerative colitis or Crohn’s disease
• Personal history of receiving radiation therapy to the abdomen or pelvic area for previous cancer treatment
• Confirmed or suspected history of colorectal cancer syndrome that is hereditary, such as familial adenomatous polyposis (FAP) or Lynch syndrome

Heredity factors and genetics play a large role in the development of colorectal cancer in susceptible populations. If you have a family member who has had colon cancer you are at a higher risk for developing colon cancer. In fact, 20% of people diagnosed with colorectal cancer have a family member who has had colon cancer. Inherited disorders, like colorectal cancer syndrome, also put you at an extremely high risk of developing colon cancer at a young age. Familial adenomatous polyposis (FAP) is an inherited disorder that causes people to develop multiple polyps early on in life that later develop into cancer. If you have FAP, you may develop colon cancer when you are in your thirties. Lynch syndrome is also known as hereditary nonpolyposis colorectal cancer or HNPCC. People with FAP or Lynch syndrome will usually begin to have therapeutic colonoscopies in their early 20s to treat and remove the multiple polyps from their colon and/or rectum. 

Having one or more of these risk factors typically means that your physican will recommend colorectal cancer screening using a colonoscopy. Remember that if a polyp or adenoma is found, the gastroenterologist can immediately remove the abnormal tissue and test for malignant cells, whereas other screening methods do not have this option. 

How Often Should You Get a Colonoscopy

The American Cancer Society, CDC, American College of Gastroenterology, and gastroenterologists worldwide agree that people should begin screening for colorectal cancer by the age of 50, if not earlier based on your risk factors. The time of the next colonoscopy occurs at different intervals depending on the individual. Generally, people who had a colonoscopy with negative findings, or no polyps found, will need to repeat screenings every 10 years until the age of 75. 

After your first colonoscopy, the next time your screening should occur depends on findings from the procedure itself, pertaining risk factors, and when you and your physician decide is best. For instance, if you had polyps removed during the colonoscopy you typically will return for your next one within 5 years. If you have a high risk for developing an adenoma, the precancerous type of polyp, you will need a colonoscopy in 2 years. People with preexisting conditions, such as irritable bowel syndrome (IBS) or diverticulosis will need to space the time between colonoscopies more often than people at an average risk for colon cancer. Recommended interval times for colorectal screenings usually are as follows:

• Every 10 years after the age of 50
• Every 5 years after the age of 60 if your risk for cancer increases
• Every 5 years if you have had a polyp removed or a polypectomy
• Every 2 years if you are at a high-risk for developing an adenoma

After the age of 75, your risk for developing complications from the bowel preparation and procedure of a colonoscopy greatly increases. Typically, by this age you are not asked to get a colonoscopy to screen for colorectal cancer any longer because the risk of complications often outweighs the benefits of the screening.

What Populations Are At High Risk For Colon Cancer?

There are several risk factors that place people at a higher risk for developing colon cancer. These include:

• Age – people between the ages of 50-75
• Family history  of colorectal cancer
• Family history of inherited colorectal syndromes, including Lynch syndrome and Incomplete removal of adenoma and/or polyp
• History of intestinal lining disorders, for example diverticulosis
• History of inflammatory bowel disease,  such as ulcerative colitis or Crohn’s disease
• Past radiation treatment to abdomen or pelvic region
• Prior abdominal or pelvic surgery
• Higher number of adenoma growths
• People who have poor economic resources
• African-American descent
• Hispanic descent

Age is the number one risk factor in the development of colorectal cancer with 90% of people who are diagnosed with the disease being over the age of 50.  However, you are able to lower your risk for colon cancer by screening regularly for colorectal cancer and avoiding lifestyle choices that increase your risk. Modifiable lifestyles and behaviors that increase your risk for colon cancer include:

• Physical inactivity
• Excessive body weight
• Poor diet high in fat and low in dietary fibers
• Smoking tobacco
• Excessive alcohol intake
• Low folate levels

You can lower your risk for developing colorectal cancer as you age by following a healthy lifestyle with a diet rich in fiber, whole grains, and low-fat protein sources. Exercise and practicing relaxation techniques are other beneficial ways to maintain good health. Poor lifestyle choices like eating processed foods, smoking and drinking alcohol all increase your risk for developing cancer. Socioeconomic factors and ethnicity also place people at a higher risk because poor access to resources place people at a high risk for being diagnosed in the later stages of the disease. Improvement in healthcare and inclusive outreach programs that serve to offer colon cancer screenings to the underprivileged, African-American and Hispanic communities markedly reduce the incidence and mortality rates in these populations.

How Often People With Pre-existing Conditions or Diseases Should Get a Colonoscopy

As discussed earlier, certain conditions and diseases place people at a higher risk for developing colon cancer which requires them to get a colonoscopy more often than those who are at an average risk. Inflammatory bowel diseases, such as Crohn’s disease or ulcerative colitis, are characterized by a chronic inflammation of the intestinal lining that may cause the development of lesions or ulcers. People who have IBD are at an increased risk for developing colon cancer because these lesions may become cancerous with time. Inherited colorectal syndromes, like FAP and Lynch syndrome, also are closely related with colon cancer due to the high number of polyps and abnormal tissue growths found in the intestinal lining in those people with the syndrome. Diverticulitis is also associated with colon cancer.  The following are suggested guidelines for how often you should get a colonoscopy if you have a gastrointestinal condition:

• Every 2-5 years if you have ulcerative colitis and from initial diagnosis
• Every 5-8 years if you have a history of diverticulitis and from initial diagnosis
• Every 2 years if you have Crohn’s disease and from initial diagnosis (some physicians advise every year depending on severity)
• Every 1-2 years if you have a hereditary colorectal syndrome such as Lynch syndrome or FAP (beginning at age 25)

People who have these conditions or diseases are prompted to screen for colon cancer at shorter intervals than the average risk populations. Regular colonoscopies at the suggested intervals increases the likelihood of catching colorectal cancer at its earliest stage when it is highly treatable. Discuss with your doctor if you have any concerns about when and if you should begin screening for colonoscopy. 

References

Engel, C., et., al. (2010, February 01). Efficacy of annual colonoscopic surveillance in individuals with hereditary nonpolyposis colorectal cancer. Clinical Gastroenterology and Hepatology, 8(2), 174-182. Retrieved from CGH Journal: https://www.cghjournal.org/action/showPdf?pii=S1542-3565%2809%2901013-1

Friedman, S., et., al. (2001, March). Screening and surveillance colonoscopy in chronic Crohn’s colitis. Gastroenterology, 120(4), 820-826. Retrieved from PubMed: https://pubmed.ncbi.nlm.nih.gov/11231935/

Jewell, T. (2020, November 17). Deciding how often you need a colonoscopy. Retrieved from Healthline: https://www.healthline.com/health/how-often-should-you-have-a-colonoscopy

Keller, D. S., Windsor, A, Cohen, R., & Chand, M. (2019, January). Colorectal cancer in inflammatory bowel disease: review of the evidence. Techniques in Coloproctology, 23(10), 2-13. Retrieved from PubMed: https://pubmed.ncbi.nlm.nih.gov/30701345/

Shaukat, A., et., al. (2021, March 01). ACG clinical guidelines: Colorectal screening 2021. American Journal of Gastroenterology, 116(3), 458-479. Retrieved from PubMed: https://pubmed.ncbi.nlm.nih.gov/33657038/