Clinical Laboratory Tests Offer Line of Defense Against Colorectal Cancer
America’s clinical laboratories play a critical role in the prevention and detection of colorectal cancer, as well as in the identification and monitoring of appropriate therapies. Colorectal cancer is the second deadliest cancer in the United States affecting both men and women. This Colorectal Cancer (CRC) Awareness Month, ACLA adds its voice to those raising awareness of CRC and is highlighting the value of non-invasive screening and diagnostic tests performed by clinical laboratories.
In 2019, the U.S. Centers for Disease Control and Prevention (CDC) reported 142,462 new cases of CRC in the United States alone. Fortunately, increased screening has led to a 25.5 percent reduction in CRC incidence and a 52.4 percent reduction in CRC deaths between 2000 and 2015.
It is estimated that one in three adults are not up to date with the CDC’s recommended screening guidelines for CRC. In fact, over 75 percent of people who died from CRC did not receive a recommended screening test. Most people should begin screening for CRC at age 45, then continue screening at regular intervals. Some individuals should be screened earlier, especially if they have an inflammatory bowel disease, family history of CRC, or a genetic syndrome such as familial adenomatous polyposis (FAP) or hereditary non-polyposis colorectal cancer (Lynch syndrome).
Colorectal cancer screening through clinical laboratory tests is very effective and paramount to determining patient care pathways. For patients diagnosed with CRC, laboratory-run genetic tests can help identify the right medication and guide disease management decisions. Identification of disease-causing genetic variants can guide further testing and diagnosis of individuals with a family history of certain inherited disorders leading to CRC.
Clinical laboratory tests, including recent innovations such as DNA-based stool or blood sample tests, help identify CRC in its earliest stages, when it is most treatable. Laboratory tests work to detect the disease in different ways:
- The fecal immunochemical test (FIT) looks for blood hidden in the stool
- The guaiac-based fecal occult blood test (gFOBT) generates a chemical reaction to find blood hidden in the stool
- A stool DNA test looks for abnormal sections of DNA from cancer or polyp cells as well as for hidden blood
- A test can detect signs of CRC via molecular material in a blood sample.
Patients should follow the screening interval recommendations for the type of test they use.
Clinical laboratories are making a difference saving and improving lives. By encouraging patients to receive their recommended screenings — either through non-invasive laboratory tests or endoscopic methods — and enabling clinicians to personalize CRC treatment through specialized laboratory testing, we can make strides toward significantly reducing incidence and death from CRC.
For more information about colorectal cancer, visit https://www.cdc.gov/cancer/colorectal/index.htm.
 Levin, T. R., Corley, D. A., Jensen, C. D., Schottinger, J. E., Quinn, V. P., Zauber, A. G., … & Doubeni, C. A. (2018). Effects of organized colorectal cancer screening on cancer incidence and mortality in a large community-based population. Gastroenterology, 155(5), 1383-1391.