At Home Colorectal Cancer Screening: Who is Eligible, How Often, and What Factors Increase Your Risk

At Home Colorectal Cancer Screening Guidelines

In 1995, the United State Preventive Services Task Force (USPSTF) recommended that cancer screening should occur for all people over the age of 50 who are at an average-risk for colorectal cancer. Then, in October of 2020, as the rates for colon cancer began to rise in younger adults, the USPSTF issued a draft that lowered the recommended age for screening to 45. The American Cancer Society agrees with this recommendation of screening for those 45 and older. This means that millions of people (at least 20 million) will need to be screened for colorectal cancer above those currently due for screening who are over the age of 50. 

The sheer number of people needing screening urges physicians to offer several options to their patients so they will follow through with the recommended guidelines. Home colorectal cancer screening is often a preferred choice for people who do not want to undergo the intense bowel preparation and invasive exploration that involves getting a colonoscopy.  

There are currently three types of stool tests that are approved for colorectal cancer screening in the United States. These include:

Fecal immunochemical test (FIT).  This test uses antibodies that specifically react with a blood protein in the stool. Physicians typically order the test to be repeated annually. 

Guaiac-based fecal occult blood test (gFOBT). Conducted yearly, the gFOBT uses a chemical (guiac) to detect microscopic amounts of blood in the stool. 

Stool DNA test (also known as FIT-DNA test). The most current stool test combines the FIT test with a test that can detect abnormally mutated DNA in the stool. Unlike the FIT and gFOBT, a stool DNA test can be repeated every three years if no abnormalities are found. 

All of these at home cancer screening tests follow the same general procedure. Using a kit, you collect a sample of your stool then mail the sample to a laboratory for analysis or to your physician. It is up to you and your physician which at home colon cancer screening test is best for you. 

Who is Eligible / Recommended For an at Home CRC Screening

You are recommended to get an at home colorectal cancer screening if you are at an average risk. You are considered at ‘average risk’  if you do not have any of the following:

• 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

Having one or more of these risk factors means that you are not recommended to screen for colorectal cancer at home. Instead, a colonoscopy is the preferred option because if a polyp or adenoma is found the gastroenterologist can immediately remove the abnormal tissue and test for malignant cells. 

If you are an average risk for colon cancer then you are eligible for at home colon cancer screening. You have three choices for these at home screenings including the FIT, FOBT, and Cologuard™. Discuss with your doctor which is the best option. The FIT (fecal immunochemical test) is the test most often prescribed by physicians due to its highly sensitivity or ability to detect small amounts of hidden blood in stool samples. Hidden blood, or occult blood, can indicate the presence of a polyp, adenoma, or a bleeding ulcer in the lower intestine. 

How Often Should You Get an at Home Colon Cancer Screening

The guidelines for how often you need to get an at home colon cancer screening is different for each test. The recommended time period for each stool-based test are as follows:

• Fecal immunochemical test (high-sensitivity) – once a year
• Guaiac-based fecal occult blood test (high-sensitivity) – once a year
• Multitarget stool DNA test (Cologuard™) – once every 3 years

The multitarget stool DNA test (also known as Cologuard) was approved by the Food and Drug Administration in August of 2014. The same year Medicaid approved of the test to be covered for those taking the test.  FIT and FOBT need to be repeated every year. Both tests detect small amounts of  blood, but have a lower sensitivity in detecting very small polyps and the precancerous adenomas. 

Important performance findings of at home screening tests include:

• Cologuard: Has a 92.3% sensitivity for detecting colon cancer at all stages 
• Cologuard: 94% of early stage colon cancers are sensitive to the Cologuard test
• FIT: FIT has a specificity of 90% for ruling out the presence of polyps and colon cancer  
• Cologuard: Has a specificity of 95% for ruling out the presence of polyps and colon cancer

Cologuard is highly sensitive due to its ability to identify cancerous cells using DNA-detecting technology. Because of these accurate ratings, Cologuard tests can be repeated every three years in average risk patients. Keep in mind that if you test positive in any of the home screening tests, you will need a colonoscopy to locate the source of the bleed and get any associated polyps removed. If there are any polyps found or abnormal tissue growths (adenomas), you may not be eligible for home screenings from that point on. 

What Populations Are At High Risk For Colon Cancer?

There are several risk factors that put people at a higher risk for developing colon cancer: 

• Advanced age in men and women
• Personal history of diverticulosis
• Personal history of inflammatory bowel disease, ulcerative colitis, or Crohn’s disease
• Prior abdominal or pelvic surgery
• Higher number of adenoma growths
• Family history  of colorectal cancer
• Family history of inherited colorectal syndromes, including Lynch syndrome and FAP
• Incomplete removal of an adenoma and/or polyp
• People who have poor economic resources
• African-American descent
• Hispanic descent

As you age, your risk for developing colon cancer increases. The number one population who is at high risk is people between the ages of 50 and 75. However, you are able to lower your risk for colon cancer 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. 

If you have a family member who has had colon cancer you are at a higher risk for developing colon cancer. 20% of people diagnosed with colorectal cancer have a family member who has had colon cancer. This means that if you have a first degree relative (like your parent, sibling, or grandparent) with colon cancer you are typically not eligible for a home cancer screening. 

When and How Often Should People at High-Risk Screen for Colon Cancer? 

If you are at a high risk for colon cancer you will need to be more vigilant at an earlier time than those at an average risk. Typically, it is recommended that you begin screening before the age of 45 if you have any of the following associated risks:

• Personal history of polyps and/or adenomas
• Personal history of inflammatory bowel disease
• Family history of FAP
• Family history of hereditary non-polyposis colon cancer
• Having a close relative who has had colorectal disease or polyps before the age of 60
• Having two first degree relatives who have had colon cancer at any age

You can discuss with your doctor if at home colon cancer screening is appropriate for you if you have one or more of the above risk factors. In many cases, physicians will advise that you get a colonoscopy instead of screening at home. 

At home screening tests are not intended to replace a diagnostic colonoscopy or a surveillance colonoscopy in those patients who are at an elevated risk for developing colon cancer. However, in some cases a colonoscopy can aggravate symptoms in people with intestinal disorders and the examination can miss lesions. For example, people with inflammatory bowel disease are more willing to get the noninvasive Cologuard test than a colonoscopy. The test is highly effective in identifying colorectal lesions in patients with IBD whereas a colonoscopy might miss the abnormal tissue due to the inflammation of the intestinal lining. If you have inflammatory bowel disease, such as Crohn’s or ulcerative colitis, discuss with your doctor if Cologuard is an option for you before a colonoscopy. 

References

American Cancer Society. (2020, November 17). American Cancer Society guidelines for colorectal cancer screening. Retrieved from American Cancer Society: https://www.cancer.org/cancer/colon-rectal-cancer/detection-diagnosis-staging/acs-recommendations.htm

Felson, S. (2020, July 24). Colon cancer screening guidelines. Retrieved from WebMD: https://www.webmd.com/colorectal-cancer/guide/colon-cancer-screening-guidelines#1-2

Mann, D. (2021, May 20). Risk factors that raise odds for early-onset colon cancer. Retrieved from WebMD: https://www.webmd.com/colorectal-cancer/news/20210520/risk-factors-that-raise-odds-for-early-onset-colon-cancer

Mayo Clinic Staff. (2014, December 03). Cologuard primed to change landscape of CRC screening. Retrieved from Mayo Clinic: https://www.mayoclinic.org/medical-professionals/digestive-diseases/news/cologuard-primed-to-change-landscape-of-crc-screening