SUMMARY: The American Cancer Society estimates that approximately 140,250 new cases of ColoRectal Cancer will be diagnosed in the United States in 2018 and about 50,630 patients are expected to die of the disease. The lifetime risk of developing CRC is about 1 in 21 (4.7%). ColoRectal cancer (CRC) is the fourth most common cancer diagnosed among adults in the US and the second leading cause of death from cancer.

The ACS recently updated Colorectal Cancer Screening Guideline using prevailing evidence as well as microsimulation modeling analyses, and included a new evaluation of the age, to begin screening by race and sex and additional modeling that incorporates changes in United States CRC incidence. The ACS Guideline Development Group applied the Grades of Recommendations, Assessment, Development, and Evaluation (GRADE) criteria in developing and rating the recommendations. The new guideline does not prioritize among screening test options. This is because test preferences vary among individuals and the guidelines development committee emphasized that screening rates could be improved by endorsing the full range of tests without preference.

Even though the incidence of Colorectal cancer (CRC) in the United States has been rapidly declining overall in people 55 and over primarily driven by screening, among adults younger than 55 years there was a 51% increase in the incidence of colorectal cancer (CRC) from 1994 to 2014 and a 11% increase in deaths from 2005 to 2015. Adults born around 1990 have twice the risk of colon cancer and four times the risk of rectal cancer compared with adults born around 1950, who have the lowest risk. Studies suggest that the younger individuals will continue to be at a higher risk as they age. The increase in the incidence of CRC in young adults has been attributed to western life style including high carbohydrate, high fat, low fiber diet which can initiate inflammation and proliferation in the colonic mucosa within two weeks. Other lifestyle factors associated with CRC include obesity, high consumption of processed meat and alcohol, low levels of physical activity and cigarette smoking. Further, young patients are 58% more likely than older patients to be diagnosed with advanced versus localized stage CRC, due to delayed follow up of symptoms, sometimes for years, and these young adults are less likely to be screened for colon cancer, despite their symptoms.

The current ACS recommendations are as follows:

1) Adults aged 45 and older with an average risk of colorectal cancer should undergo regular screening with either a high-sensitivity stool-based test or a structural (visual) exam, depending on patient preference and test availability.

2) As a part of the screening process, all positive results on non-colonoscopy screening tests should be followed up with timely colonoscopy.

3) The recommendation to begin screening at age 45 years is a “qualified recommendation”. The change in starting age is designated as a “qualified recommendation” because there is less direct evidence of the balance of benefits and harms, or patients’ values and preferences, related to colorectal cancer screening in adults aged 45 to 49, since most studies have only included adults aged 50 and older.

4) The recommendation for regular screening in adults aged 50 years and older is designated as a “strong recommendation,” on the basis of the greater strength of the evidence and the judgment of the overall benefit.

5) Average-risk adults in good health with a life expectancy of greater than 10 years should continue colorectal cancer screening through age 75 years.

6) Clinicians should individualize colorectal cancer screening decisions for individuals aged 76 through 85 years, based on patient preferences, life expectancy, health status, and prior screening history.

7) Clinicians should discourage individuals over age 85 years from continuing colorectal cancer screening.

Test options for CRC screening include the following:

Stool-based tests

1) Highly sensitive Fecal Immunochemical Test (FIT) annually

2) Highly sensitive guaiac-based Fecal Occult Blood Test (gFOBT) annually

3) Multi-targeted stool DNA test every 3 years

Visual exams

1) Colonoscopy every 10 years

2) CT colonography (virtual colonoscopy) every 5 years

3) Flexible sigmoidoscopy every 5 years

Colorectal cancer screening for average-risk adults: 2018 guideline update from the American Cancer Society. Wolf AM, Fontham ET, Church TR, et al. CA Cancer J Clin 2018;68:250-281.