Purpose Statement and Intended Audience
This is the second installment in the colorectal cancer prevention series. This article is intended for adults who fall within the recommended age range (45 to 75 years old) for colorectal cancer screening. This article aims to provide up-to-date information about several approved options available for colorectal cancer screening.
What options do you have for colorectal cancer screening?
Colorectal cancer screening allows medical teams to detect colorectal cancer early. If cancer is found, early detection increases the likelihood of success of cancer treatment. Colorectal cancer remains a top cause of cancer deaths, despite the availability of several ways to screen for it. Late diagnosis is one reason colorectal cancer poses a serious health burden (Glaser, 2024). Fortunately, prevention and early detection (i.e., identifying precancerous polyps before they turn into cancer) are possible. Read about colorectal cancer prevention and screening guidelines here.
The information below describes in detail a variety of available colorectal cancer screening options. Use this information to learn about your options and talk to your doctor about which option may be best for you.
Colonoscopy
Colonoscopies are one of the more common and well-known screening procedures. A colonoscopy is completed during a scheduled visit at a clinic or medical office. A colonoscopy uses a long flexible scope with a camera at the end which is inserted into the rectum. As the scope travels throughout the colon, the doctor searches for polyps, growths, irritation of the bowel, or any other unusual signs in the bowel (American Cancer Society, 2024a). Sometimes, samples of abnormal regions, also known as biopsies, may be taken to determine whether an abnormality is cancerous or not. Polyps or other abnormalities may also be removed during the screening procedure.
- A colonoscopy should be done every 10 years, starting at the age of 45, in persons of average risk. It is one of the most thorough tests for colorectal cancer screening available.
Before the Colonoscopy
Follow your provider’s instructions for bowel prep. This can include but is not limited to adjusting your diet and medications and taking a laxative to avoid blockages. Make sure to speak with your provider to find the right bowel prep for you (American Cancer Society, 2024a). Bowel prep allows the doctor a clear view of the tissues and linings of the colon. Most patients are sedated for the colonoscopy procedure; the sedation facilitates a more thorough exam with less discomfort. Rarely are patients not sedated.
Flexible Sigmoidoscopy (FSIG)
The flexible sigmoidoscopy is like a colonoscopy, in that a thin flexible tube with a camera at the end is inserted into the rectum. The FSIG examines the lower part of the large intestine. Biopsies can also be obtained through this exam (American Cancer Society, 2024b). Unlike colonoscopy, which explores both the upper and lower halves of the large intestine, FSIG only examines the lower portion of the large intestine. Some people might choose to undergo FSIG because it is considered less invasive, has easier bowel prep, and poses a lower risk of bowel perforation (which is an uncommon risk) compared to colonoscopy. To prepare for the FSIG, you should follow dietary restrictions and bowel preparation specified by your doctor.
- The FSIG test should be repeated every 5 years, starting at 45 years old.
- If paired with a yearly FIT, the FSIG test should be done every 10 years.
Home Screening Tests
Stool-based tests are another option for colorectal cancer screening. One benefit of this screening type is that it can be completed from the comfort of your own home. A stool-based test can be mailed to your home, where you would provide the stool sample (also known as poop). You would then follow the detailed instructions in the screening kit to mail the stool sample back to the clinic for analysis. These tests are non-invasive options for adults at average risk. Below are detailed descriptions of the three types of stool-based tests that are commonly administered:
- Fecal immunochemical test (FIT): The FIT is an at-home testing kit that requires you to collect your own stool sample, which will then be sent out to a lab for testing. The kit comes with step-by-step instructions on how to properly collect and send out your stool sample for analysis. The FIT tests for hidden and unnoticeable blood in a fecal sample, which could be an early symptom of colorectal cancer (American Cancer Society, 2024b). The FIT, however, is less likely to react to bleeding from the upper gastrointestinal tract, meaning that bleeding from the upper intestines could go unnoticed with the FIT (American Cancer Society, 2024b). The FIT has attributes that some find appealing. The FIT does not require any prep or dietary restrictions prior to collection. Additionally, many report feeling comfortable with the idea of using FIT because it can be done at home, which provides an increased sense of privacy. Finally, many consider the FIT easy to use.
- The FIT test is conducted annually, starting at the recommended screening age of 45. If blood is detected from the FIT results, the next step would be to complete a colonoscopy.
2. Guaiac-based fecal occult blood test (eFOBT): Like the FIT, the eFOBT test is also an at-home kit that checks for hidden blood in stool. Instructions on how to collect and mail your sample are outlined in the kit, making this test extremely user friendly. However, unlike the FIT, there are dietary restrictions that should be followed when using the eFOBT because some items can affect the accuracy of the test. For three days before using eFOBT, it is recommended to avoid intake of anti-inflammatory drugs, excess Vitamin C (more than 250 mg [about the weight of ten grains of rice] a day), and red meats (American Cancer Society, 2024b).
- Like the FIT, the eFOBT should be conducted once a year, starting at the recommended screening age of 45. The eFOBT is a good option if you are at average risk for colorectal cancer.
3. Stool DNA test: The stool DNA test looks for and analyzes hidden blood and cell DNA in stool samples. One stool DNA test used in the United States is Cologuard®. When a polyp or cancerous growth develops in the colon, it causes changes or mutations in the genes of your cells. A stool DNA test analyzes the cells in the stool sample for any mutations to determine if any abnormalities are present in your colon and rectal area (American Cancer Society, 2024b). Like the previously described stool-based tests, the stool DNA screening method can be completed at home and comes with detailed instructions on how to collect and send out your stool sample. Additionally, if blood and/or changes to the DNA are detected, the next step will involve a colonoscopy to determine the source of these abnormalities.
- The stool DNA test is recommended to be done every 3 years, starting at the screening age of 45.
CT Colonography
The CT colonography is a less invasive version of colonoscopy. CT colonography is also known as virtual colonography. During this screening process, images are obtained from a CT scan and provide a full view of the colon and rectum (American Cancer Society, 2024b). This process allows imaging to be obtained without the discomfort of having a camera placed through the rectum (as is done with colonoscopy). This test is recommended for people who are of average risk for colorectal cancer, are hesitant about colonoscopies, have clotting abnormalities, or have a bowel obstruction. CT colonography can detect polyps at least 1 cm in size, with the added advantage of being able to detect abnormalities outside of the colorectal area due to the extensive imaging of the entire abdomen. However, CT colonography may miss polyps smaller than 1 cm. It is also an expensive test that may not be covered by insurance in all instances. To prepare for a CT colonography, the bowel must be empty. It is recommended to consult with your provider to determine the best bowel prep for you (American Cancer Society, 2024b).
- If using this method of screening, you should have a CT colonography done every five years, starting at the age of 45.
How you choose to screen is between you and your doctor, but it is important to get and remain within guidelines for colorectal cancer screening. Do not be afraid to explore your options and consult your doctor to find out which test is best for you.
How to Determine Which Screening Test to Complete
Many adults who reach the recommended screening age of 45 years old appreciate the fact that they can complete a colonoscopy once every 10 years. However, it is not uncommon for people to experience anxiety or hold stigmas around colonoscopies. If this is the case for you, talking with your doctor about the best option for you may be a good place to start. You may also consider one of the accurate and reliable at-home screening options described above. At-home screening tests are convenient, and there is strong evidence for their use. If the results of the at-home test are positive, then it is important to follow up with your provider, who may recommend additional tests (usually a colonoscopy) to look for signs of cancer in the colon.
Screening decisions are based on a combination of your choice and your doctor's recommendation. You and your provider can discuss the screening methods available to you, based on your risk factors, so you can make an informed choice about how you want to get screened. This process is called shared decision making and is a critical component of all patient-provider relationships. There is no need to compromise on your health and patient choice is often the most important aspect to getting screened. The important thing is just to get screened in some way.
How to Access Screening in Your Florida Community
The first way to explore screening options is to speak with your primary care provider about the screening options available to you. If you do not have a primary care provider, there are many resources to help you navigate colorectal cancer screening (Table 1). Among the many options, the UF Health Cancer Center is one resource that can help connect individuals living in Florida to cancer screening services that are convenient and available at no cost.
UF Health Cancer Center Screening Resources and Navigation
If you reside in Florida, you can contact the UF Health Cancer Center’s Cancer Screening and Care Navigation team by calling (352) 359-5184 to learn more about its clinic locations and at-home screening kits that may be available to you. If you do not have a primary care provider or are unable to get an appointment at a time that is convenient for you, the navigation team can also assist you in scheduling with the UF Mobile Outreach Clinic. The UF Mobile Outreach Clinic team provides all primary care services at no cost to the patients and has clinic sites in Gainesville, Florida.
Table 1. Information on accessing screening resources throughout Florida.
Additional Considerations for Colorectal Cancer Screening
Why is understanding high risk versus average risk for colorectal cancer important?
Many people are unaware of their risk for colorectal cancer. You may be asking yourself, how does risk level affect my screening options? Simply, your recommended screening options may be different if you are at high versus average risk for getting colorectal cancer. Risk assessment is based on modifiable risk factors (lifestyle choices) and nonmodifiable risk factors (e.g., family or personal history of polyps or cancer, preexisting conditions like ulcerative colitis or Crohn’s disease, DNA and genetic predispositions). Your risk status (high versus average) will inform the frequency (how often you should obtain screening) and type of screening method your doctor recommends.
The screening guidelines discussed in this article are intended for individuals with average risk, meaning there are no known risk factors for colorectal cancer, including family history, history of polyps, obesity, alcohol use, or smoking. If you believe you are not at average risk, you can speak to your provider to learn about your unique screening needs. Your provider can discuss how frequently and what type of screening you should seek.
- What places someone at high risk for developing colorectal cancer? If you have family members affected by colorectal cancer, you may have a genetic predisposition to colorectal cancer. This means that you might have a genetic marker which gives you a higher chance of developing colorectal cancer. Outside of genetics, there are lifestyle choices that increase your risk for colorectal cancer, including excess drinking, smoking, red and processed meat consumption, and a lack of exercise.
- How does being at high risk affect my screening options? For individuals considered high risk, the recommended screening options for colorectal cancer may be different. The stool-based tests are not typically recommended for people with high colorectal cancer risk. Rather, you will most likely be advised to obtain a colonoscopy to get a clear and thorough view of the colon and rectum. It is important to talk to your provider to discuss your screening options and understand what choices you have.
- What places someone at average risk for developing colorectal cancer? If you have no genetic predisposition to, or family history of, colorectal cancer, it is likely that you are at average risk for colorectal cancer. If you limit your drinking, do not smoke, exercise regularly, and limit your red and processed meat consumption, you are further lowering your risk of colorectal cancer.
- How does being at average risk affect my screening options? If you are of average risk, any of the screening methods described in this article are considered appropriate options to remain within screening guidelines for colorectal cancer. Remember that one’s general risk level is not a guarantee of complete safety from colorectal cancer. It is important to get screened and stay up to date with colorectal cancer screenings. Being of average risk does, however, give you a bit more flexibility to choose your preferred screening methods, which may include any of the at-home stool tests.
What happens if a colorectal cancer screening test detects an abnormality?
Many people each year will complete colorectal cancer screening tests that detect an abnormality. If you find yourself in this situation, you are not alone. In 2024, it is predicted that 106,590 new cases of colon cancer and 46,220 new cases of rectal cancer will be diagnosed nationally (American Cancer Society, 2024c). According to the FL Health Charts, Florida’s reported colorectal cancer incidence rate in 2021 was 36.3 per 100,000 individuals (for reference, the seating capacity of the Ben Hill Griffin Stadium is 88,548). This means about 36 out of 100,000 Floridians received a new diagnosis of colorectal cancer in 2021. Incidence rates vary throughout the state: for example, Liberty County, FL has the lowest rate of 8.2 per 100,000 compared to Union County, FL, where 94.5 adults out of 100,000 received a new diagnosis of colorectal cancer in 2021. You can explore rates for your county here: Colorectal Cancer Incidence - FL Health CHARTS - Florida Department of Health | CHARTS (FL Health Charts, 2024).
Now that we have discussed the specifics of how to screen, and options to access screening, you might be wondering what happens once you complete your colorectal cancer screening. Below we describe what a positive finding means when found on a home-stool test or colonoscopy and discuss what to do next.
- Abnormality found in home-stool test: If an abnormality is found from the home-stool test, you may be encouraged to get a colonoscopy. This is because a colonoscopy provides a more complete view of your colorectal tract polyps removed, and biopsies of abnormal tissue obtained (American Cancer Society, 2024b). Contact your health care provider to schedule the appropriate follow-up screening if you experience a positive result on a home-stool test.
- Abnormality found during colonoscopy: If an abnormality is found during a colonoscopy, the doctor can take a sample (also called biopsy) of the abnormal tissue and test if those cells are cancerous (American Cancer Society, 2024a). After this biopsy, your doctor will call you with the results. A follow-up appointment may be made to discuss these results as well. If a concerning abnormality is found, your care team may recommend additional testing or provide a referral to additional medical teams (American Cancer Society, 2024a). It may be the case that a harmless irregularity is found, and your doctor may recommend that you complete your next colonoscopy in 5 or 7 years (rather than at the typical 10-year interval).
How do I talk to my care team or family members about screening?
Talking about colorectal cancer screening experiences and the variety of options available for screening may help adults who feel hesitant become more comfortable about the topic.
- Memorable messages: Stories of good outcomes after obtaining colorectal cancer screening can be a powerful source of social influence and increase others’ willingness to screen (Kruse-Diehr et al., 2022). Too often, the stories we hear about screening can leave us feeling uneasy, as expressed by the following account: “… I think we often listen to people’s horror stories of how [colonoscopy] is done... [but] you have to remember [not to] listen to people’s horror stories... By not doing anything in the next five or six, 10 years, you [can] end up with colon cancer” (Kruse-Diehr et al., 2022). Furthermore, research indicates that it is important to hear information about colorectal cancer screening from trusted sources including cancer survivors and familiar local health professionals. Sometimes it is not the colonoscopy itself, but the preparation that causes hesitation. Thus, sharing experiences and encouragement to screen, including messages about the preparation process, may help to break down barriers to screening (Weaver, 2015).
Examples of shared experiences that acknowledge the importance of staying up to date with recommended screening can be found throughout the screening literature. There are multiple reported patient experiences with colonoscopies. Some narratives describe the screening encounter positively. In one research study, a participant stated that they were “really surprised how easy it all was… It wasn’t bad or painful and I was really surprised at the whole experience” (Mikocka-Walus et al., 2012). Another comment indicated that “... my nervousness [was] for nothing… because it’s so easy and fast” (Mikocka-Walus et al., 2012).
Several adults lament the lack of discussion that exists when it comes to getting screened for colorectal cancer. One person discussing this topic indicated, “To be frank with you, sometimes in our culture, sometimes in our community, the understanding, the educational aspect, and all of the importance has been limited [in the Black community] for some reason” (Kruse-Diehr et al., 2022). Another person mentioned, “[m]y doctor has never said anything like that to me, like a FIT test” (Kruse-Diehr et al., 2022). These statements highlight the desire and need for more discussions about how to screen for colorectal cancer.
For adults who may fall into the high-risk category, fear of finding cancer due to the screening process can be a barrier. When interviewed about the screening experience, one adult who was at high risk due to family history stated that she gets “a bit worried about what they might find, but ... well ... [she doesn't] want cancer” (Mikocka-Walus et al., 2012). As these few examples of patient encounters show, the fear of colonoscopies is not uncommon, but those who have gone through the process find important reasons to ultimately follow through with screening, including increased peace of mind post-procedure due to the thorough nature of the exam.
Finally, remember that while colonoscopies may be the most common option due to their high accuracy, there are additional screening options available to the public. If a colonoscopy is out of your comfort zone due to fear of sedation, difficulties with scheduling an appointment, or travel barriers, you can still obtain recommended and lifesaving colorectal cancer screening by asking your doctor about one of the other screening modalities outlined above in the “What options do you have for colorectal cancer screening?” section.
Conclusion
Colorectal cancer is a serious illness. When left untreated or detected at a late stage, it can have fatal consequences. Importantly, there are several approved screening options available to help adults prevent or detect colorectal cancer early when it is still treatable. If you are at the age of 45, it is time to talk to your doctor about getting screened for colorectal cancer. Data from the US Preventive Services Task Force (USPSTF) confirms that screening saves lives. Overall, regardless of the type of screening test, screening at 45 years of age is estimated to prevent between 2 and 3 colorectal cancer cases annually for every 1,000 people who are screened compared to screening at age 50.
Speak to your health care provider about colorectal cancer screening and make an informed choice that feels right for you. If you still have questions, consulting informed sources such as local educators or members of the community with relevant experience may increase trust and motivation to obtain colorectal cancer screening (Kruse-Diehr et al., 2022).
References
American Cancer Society Medical and Editorial Content Team. (2024a). Colonoscopy. https://www.cancer.org/cancer/diagnosis-staging/tests/endoscopy/colonoscopy.html
American Cancer Society Medical and Editorial Content Team. (2024b). Colorectal Cancer Screening Tests. https://www.cancer.org/cancer/types/colon-rectal-cancer/detection-diagnosis-staging/screening-tests-used.html
American Cancer Society Medical and Editorial Content Team. (2024c). Key Statistics for Colorectal Cancer. https://www.cancer.org/cancer/types/colon-rectal-cancer/about/key-statistics.html
FLHealthCharts. (2021). Colorectal Cancer Incidence. Retrieved on March 27, 2024. https://www.flhealthcharts.gov/ChartsDashboards/rdPage.aspx?rdReport=NonVitalInd.Dataviewer&cid=0445.
Glaser, K. M., Crabtree-Ide, C. R., McNulty, A. D., Attwood, K. M., Flores, T. F., Krolikowski, A. M., Robillard, K. T., & Reid, M. E. (2024). Improving Guideline-Recommended Colorectal Cancer Screening in a Federally Qualified Health Center (FQHC): Implementing a Patient Navigation and Practice Facilitation Intervention to Promote Health Equity. International Journal of Environmental Research and Public Health, 21(2), 126. https://doi.org/10.3390/ijerph21020126
Kruse-Diehr, A. J., Cegelka, D., Holtsclaw, E., Stapleton, J., Burnett, C., Wood, R., Combs, C. & Williams, L. B. (2023). Barriers and Facilitators to Stool-Based Screening for Colorectal Cancer Among Black Louisville Residents. Journal of Cancer Education, 38(3), 1050–1058. https://doi.org/10.1007/s13187-022-02231-2
Mikocka-Walus, A. A., Moulds, L. G., Rollbusch, N., & Andrews, J. M. (2012). "It's a tube up your bottom; it makes people nervous": The experience of anxiety in initial colonoscopy patients. Gastroenterology Nursing: The Official Journal of the Society of Gastroenterology Nurses and Associates, 35(6), 392–401. https://doi.org/10.1097/SGA.0b013e318274b0c6
US Preventive Services Task Force. (2021). Colorectal Cancer: Screening. https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/colorectal-cancer-screening
Weaver, K. E., Ellis, S. D., Denizard-Thompson, N., Kronner, D., & Miller, D. P. (2015). Crafting Appealing Text Messages to Encourage Colorectal Cancer Screening Test Completion: A Qualitative Study. JMIR mHealth and uHealth, 3(4), e100. https://doi.org/10.2196/mhealth.4651