Srijesa Khasnabish, OMS-III | New York Institute of Technology College of Osteopathic Medicine
2022 Namey/Burnett Preventive Medicine Writing Award Submission

Sponsored by the ACOFP Foundation, with winners selected by the ACOFP Health & Wellness Committee, the Namey/Burnett Preventive Medicine Writing Award honors the memory of Joseph J. Namey, DO, FACOFP, and John H. Burnett, DO, FACOFP—dedicated advocates for osteopathic medicine—and recognizes the best preventive medicine blog posts submitted by osteopathic family medicine students and residents.

During my family medicine rotation, a common question I asked patients at their annual physical was: “Have you had a colonoscopy previously?” Every third-year medical student knows the United States Preventive Services Task Force’s (USPSTF) guidelines on colonoscopy screening: a colonoscopy every 10 years starting at age 50 unless a direct family member has a history of colorectal cancer (CRC). When I asked this question to a Spanish-speaking patient, she asked: “What’s that?” I responded in terms that may have been lost in translation: “It’s a procedure that helps us check the health of your rectum.” Thankfully, my attending was a native Spanish speaker who was able to thoroughly explain the significance of this test.

According to the National Cancer Institute, CRC is the fourth most common type of cancer and represents 7.9% of all new cancer cases in the United States. It is most often diagnosed among individuals aged 65–74 years old.1 CRC is the second leading cause of cancer death in the United States; lung cancer is the first.2 I was shocked to learn that CRC is more common in men than women and is more common in African Americans. How could this be possible, given the many tools that exist to screen for CRC? Before diving into this interesting statistic, let’s review some basic information on this disease.

USPSTF Guidelines and Methods for Colorectal Cancer Screening

Currently, the USPSTF recommends screening adults aged 50–75 years old for CRC (Grade A recommendation). In 2021, the USPSTF added a new “B” grade recommendation to screen adults aged 45–49. The screening intervals vary based on the type of screening test performed, with annual screening recommended if a high-sensitivity guaiac fecal occult blood test (FOBT) is performed. This screening time interval increases to every 1–3 years if a sDNA-fecal immunochemical (FIT) test is performed. The recommendations are to screen every five years if a CT colonography (virtual colonoscopy) or flexible sigmoidoscopy are performed as the screening test. Finally, CRC screening can be performed every 10 years, if a flexible sigmoidoscopy is completed with annual FIT testing, or if a colonoscopy is performed.3 While a colonoscopy requires sedation and has a slim chance of complications, it can be used for both detection and biopsy of polyps and removal of precancerous polyps in one single test.4 Colonoscopies also have the highest sensitivity for CRC compared to other screening tools.5,6

It is important to note that these recommendations apply to adults who at an average risk of developing CRC, excluding those who have a past medical history of conditions like CRC, adenomatous polyps or inflammatory bowel disease. These recommendations also exclude individuals with a family history disorders like Lynch syndrome, which increases his/her risk of developing CRC.3

Pathogenesis and the Power of Prevention

CRC develops from adenomatous colon polyps that start small but grow to more than 8 mm before undergoing dysplasia and becoming a carcinoma.7 While the progression from an adenoma to a carcinoma can take up to 10 years, better prognosis can be achieved if such polyps are detected early and biopsied.8

Risk factors for CRC are both genetic and environmental. The genetic factors include hereditary forms of CRC, age, a family history of CRC, inflammatory bowel disease and a history of abdominal irradiation.9 Potentially modifiable risk factors include obesity, diabetes, tobacco use and excessive consumption of processed meat, among others.9 However, these factors do not alter CRC screening recommendations.

The good news is that with the various screening tools available, healthcare providers have the power to prevent CRC. The earlier CRC is detected, the higher chance a patient has of five-year survival upon diagnosis. If diagnosed while in the localized stage (confined to primary site), five-year survival is as high as 90.6%. This percentage decreases to 72.2% if diagnosed once the cancer has spread to regional lymph nodes and to 14.7% if identified once the cancer has metastasized.10

Addressing Disparities in CRC Mortality

Despite the clear USPSTF guidelines and plethora of CRC screening tools, individuals of African American descent have the highest incidence of mortality from this cancer.11 Current research suggests that part of this disparity can be attributed to tumor stage, as CRC is likely to be detected at a later stage and at a younger age in African populations, which could be caused by genetic and biological factors not yet uncovered. Another factor to consider is the difference in socioeconomic status of minority populations and how this creates differential opportunities for treatment, adherence to treatment, as well as the quality of care that is accessible to the patient.12 However, even when studies are adjusted for these factors, CRC mortality is still elevated in African American populations compared to others.1

Furthermore, the rate of mortality from CRC has decreased in the past decade, but the CRC mortality rate in African Americans continues to be higher than that of Caucasians.3 This data highlights the need to develop screening tools that are better at determining CRC prognosis in African American populations, despite studies that have explored various biomarkers such as nuclear accumulation of p53 or mucin 1.12

Addressing Barriers to CRC Screening

A study by Muthukrishnan et al explored self-reported barriers to CRC screening at a safety-net healthcare setting, with African Americans as the majority of the participants who reported barriers (59.5%). The top reason reported by study participants was fear or worry related to the procedure experience, sedation process or next steps if the colonoscopy had abnormal findings. Other reasons included lack of provider referral, financial difficulties or screening as a low priority.10 This information highlights the importance of educating patients on the details of the procedure to eliminate their fears related to colonoscopies.

Despite the fear patients may have about colonoscopies, the rates of serious complications occurring from this procedure are as low as 2.8 per 1000 examinations.13 Examples of complications include cardiopulmonary complications related to sedation, complications related to preparation, bleeding secondary to polypectomy or perforation secondary to mechanical trauma or barotrauma.13 Risks can also vary with age; for instance, older patients are more likely to experience adverse reactions to sedation compared to younger patients.


CRC the fourth most common cancer in the United States. Fortunately, modern medicine has a vast set of screening tools available ranging from minimally invasive techniques, such as FOBT, to outpatient procedures, such as a colonoscopy. Even this invasive technique has a staggeringly low rate of serious complications. The current literature shows a higher rate of mortality from CRC in African American populations. Further research is needed to understand the root of this difference and if more specific screening tools can lead to a decrease in mortality. Healthcare providers need to explore and address their patients’ fears related to the CRC process to lessen this barrier to CRC screening.


  1. Cancer of the Colon and Rectum – Cancer Stat Facts. SEER. Published 2018. Accessed December 31, 2021.
  2. CDC. An Update on Cancer Deaths in the United States. Centers for Disease Control and Prevention. Published May 29, 2020. Accessed December 31, 202.
  3. Recommendation | United States Preventive Services Taskforce. Published June 15, 2016. Accessed December 31, 2021.
  4. Doubeni C. Tests for Screening for Colorectal Cancer. UpToDate. Published December 07. 2021. Accessed December 31, 2021.
  5. Zauber A, Knudsen A, Rutter CM, et al. Evaluating the benefits and harms of colorectal cancer screening strategies: A collaborative modeling approach. AHRQ Publication No. 14-05203-EF-2. Rockville, MD: Agency for Healthcare Research and Quality; October 2015.
  6. Doubeni C. Screening for colorectal cancer: strategies in patients at average risk. UpToDate. Published December 14, 2021. Accessed December 31, 2021.
  7. Winawer SJ, Fletcher RH, Miller L, et al. Colorectal cancer screening: clinical guidelines and rationale [published correction appears in Gastroenterology 1997 Mar;112(3):1060] [published correction appears in Gastroenterology 1998 Mar;114(3):625]. Gastroenterology. 1997;112(2):594–642. doi:10.1053/gast.1997.v112.agast970594
  8. Finlay, AC. Colorectal cancer: Epidemiology, risk factors and protective factors. UpToDate. Published September 22, 2021. Accessed December 31, 2021.
  9. Alexander DD, Waterbor J, Hughes T, Funkhouser E, Grizzle W, Manne U. African-American and Caucasian disparities in colorectal cancer mortality and survival by data source: an epidemiologic review. Cancer Biomark. 2007;3(6):301-313. doi:10.3233/cbm-2007-3604
  10. Muthukrishnan M, Arnold LD, James AS. Patients’ self-reported barriers to colon cancer screening in federally qualified health center settings. Prev Med Rep. 2019;15:100896. Published 2019 May 15. doi:10.1016/j.pmedr.2019.100896
  11. Whitlock EP, Lin JS, Liles E, Beil TL, Fu R. Screening for colorectal cancer: a targeted, updated systematic review for the U.S. Preventive Services Task Force. Ann Intern Med. 2008;149(9):638-658. doi:10.7326/0003-4819-149-9-200811040-00245
  12. Augustus GJ, Ellis NA. Colorectal cancer disparity in African Americans: Risk factors and carcinogenic mechanisms. Am J Pathol. 2018;188(2):291-303. doi:10.1016/j.ajpath.2017.07.023
  13. Lee L, Saltzman JR. Overview of Colonoscopy in Adults. UpToDate. Published April 21, 2021. Accessed December 31, 2021.

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