MedicalResearch.com Interview with:
Douglas A. Corley, MD, PhD
Gastroenterologist and Research Scientist III
Division of Research
Medical Research: What is the background for this study? What are the main findings?
Dr. Corley: Colorectal cancer is a leading cause of cancer death in the United States, so understanding how cancer screening tests for this cancer are used and if they are effective is extremely important.
There are two commonly used tests for colorectal cancer screening in the United States: colonoscopy and fecal immunochemical tests (also known as “FIT”). Colonoscopy requires a bowel preparation to clean you out and is invasive but, if normal, it is done infrequently (every ten years).
FIT is simple to do at home but, to be most effective, needs to be done every year. This has the advantage of potentially picking up cancers that grow between tests. There are few studies that have looked at how well FIT picks up cancers when used year after year. If a test picks up most cancers, it is said to be very “sensitive” for picking up cancer. Most studies only looked at 1 or 2 years of use for how well FITdetected cancers. It is possible that the first year of use may “clear out” most of the easily detectable cancers and that FIT might not work as well in subsequent years.
This very large study over several years at Kaisier Permanente, where we use both colonoscopy and FIT for colorectal cancer screening, looked at whether FIT worked as well at detecting cancer in years 3 and 4 as it did the first time someone used it.
We found that the sensitivity was highest in the first year, likely from clearing out cancers that were there for a while and easily detected, but that in subsequent years the sensitivity, though 5-10% lower, remained high. Also, most people who started with FIT continued doing it, suggesting that it is both feasible and effective for colorectal cancer screening.
Medical Research: What should clinicians and patients take away from your report?
Dr. Corley: There are a couple different effective tests for colectal cancer screening:, including colonoscopy and FIT. They have different strengths and weaknesses. This study provides additional support that FIT can be an important tool for getting more people screened in a way that is both sensitive to picking up cancers and that people can comply with.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Corley: It will be important to know how well colonoscopy and FIT do over long periods of time — both in terms of compliance and effectiveness. There are currently some randomized trials to look at FIT vs. colonoscopy, but we won’t have any results for several years.
Medical Research: Is there anything else you would like to add?
Dr. Corley: The most important thing is that people age 50-75 get screened for colorectal cancer. The choice of test may depend upon factors such as family history of colorectal cancer. Ask your doctor about getting screened, and choose the test you can complete.
Jensen CD, Corley DA, Quinn VP, Doubeni CA, Zauber AG, Lee JK, et al. Fecal Immunochemical Test Program Performance Over 4 Rounds of Annual Screening: A Retrospective Cohort Study. Ann Intern Med. [Epub ahead of print 26 January 2016] doi:10.7326/M15-0983
Douglas A. Corley, MD, PhD, MPH (2016). Stool Test May Get More People To Be Screened For Colon Cancer MedicalResearch.com