What new tests are being developed for colorectal cancer screening?
Researchers are studying whether DNA in stool (4, 11, 12) or blood (13) can be tested to screen for colorectal cancer. DNA is normally present in stool as a result of cells being shed from the lining of the colon and the rectum. Testing DNA in stool for certain changes may help doctors find evidence of colorectal cancer or even precancerous growths.
Research conducted thus far has shown that this kind of test has the potential to detect colorectal cancer in people who are known to have the disease, but whether this type of test can be used for screening (that is, to detect colorectal cancer in people who do not have symptoms) is not known.
Tumors also release cells, and therefore DNA, into the bloodstream, and researchers are studying whether the presence of an altered gene called SEPT9 in blood can be used to screen for early cancer and advanced adenomas (13).
In addition, several approaches that avoid the thorough cleansing of the colon that is currently required for virtual colonoscopy are being studied and refined. One approach is “fecal tagging” with a contrast agent that is ingested over several days before the procedure. This technique allows fecal material in the colon to be differentiated from colon tissue (14); computer software can be used to electronically remove the tagged fecal material from images (15).
Information about ongoing clinical trials that are studying methods for colorectal cancer screening can be found in NCI’s clinical trials database. You may also contact NCI’s Cancer Information Service at 1–800–4–CANCER (1–800–422–6237) for assistance with searching the clinical trials database or for other cancer information needs.
- American Cancer Society. Cancer Facts & Figures 2014. Atlanta: American Cancer Society; 2014. Accessed February 25, 2014.
- U.S. Preventive Services Task Force. Screening for colorectal cancer: U.S. Preventive Services Task Force recommendation statement. Annals of Internal Medicine 2008; 149(9):627-637.
- Burch JA, Soares-Weiser K, St John DJ, et al. Diagnostic accuracy of faecal occult blood tests used in screening for colorectal cancer: A systematic review. Journal of Medical Screening 2007; 14(3):132-137.
- Ouyang DL, Chen JJ, Getzenberg RH, Schoen RE. Noninvasive testing for colorectal cancer: A review. American Journal of Gastroenterology 2005; 100(6):1393-1403.
- Elmunzer BJ, Hayward RA, Schoenfeld PS, et al. Effect of flexible sigmoidoscopy-based screening on incidence and mortality of colorectal cancer: A systematic review and meta-analysis of randomized controlled trials. PLoS Medicine 2012; 9(12):e1001352.
- Schoen RE, Pinsky PF, Weissfeld JL, et al. Colorectal-cancer incidence and mortality with screening flexible sigmoidoscopy. New England Journal of Medicine 2012; 366(25):2345-2357.
- Atkin WS, Edwards R, Kralj-Hans I, et al. Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial. Lancet 2010; 375(9726):1624-1633.
- Ransohoff DF. How much does colonoscopy reduce colon cancer mortality? Annals of Internal Medicine 2009; 150(1):50-52.
- Collins JF, Lieberman DA, Durbin TE, Weiss DG; Veterans Affairs Cooperative Study #380 Group. Accuracy of screening for fecal occult blood on a single stool sample obtained by digital rectal examination: A comparison with recommended sampling practice. Annals of Internal Medicine 2005; 142(2):81-85.
- Zapka J, Klabunde CN, Taplin S, et al. Screening colonoscopy in the US: Attitudes and practices of primary care physicians. Journal of General Internal Medicine 2012; 27(9):1150-1158.
- Imperiale TF, Ransohoff DF, Itzkowitz SH, et al. Fecal DNA versus fecal occult blood for colorectal-cancer screening in an average-risk population. New England Journal of Medicine 2004; 351(26):2704-2714.
- Itzkowitz SH, Jandorf L, Brand R, et al. Improved fecal DNA test for colorectal cancer screening. Clinical Gastroenterology and Hepatology 2007; 5(1):111-117.
- Church TR, Wandell M, Lofton-Day C, et al. Prospective evaluation of methylated SEPT9 in plasma for detection of asymptomatic colorectal cancer. Gut 2014; 63(2):317-325.
- Iannaccone R, Laghi A, Catalano C, et al. Computed tomographic colonography without cathartic preparation for the detection of colorectal polyps. Gastroenterology 2004; 127(5):1300-1311.
- Zalis ME, Blake MA, Cai W, et al. Diagnostic accuracy of laxative-free computed tomographic colonography for detection of adenomatous polyps in asymptomatic adults: A prospective evaluation. Annals of Internal Medicine 2012; 156(10):692-702.
Source: National Cancer Institute