The Advantages of FIT
Traditionally colon screening in Canada has used the guaiac FOBT (fecal occult blood test), however Colon Check will be using the Fecal Immunochemical Test (FIT).
The FIT has been available in other countries for several years and has recently been approved for use in Canada.
The FIT uses monoclonal or polyclonal antibodies directed against human globin.
The advantages of the FIT over the traditional guaiac FOBT include the following:
- Improved detection of colorectal cancer
- Improved detection of high-risk adenomas
- Specific for human hemoglobin
- Will not cross-react with dietary peroxidase
- Likely more specific for colorectal sources of blood
- Automated to improve quality control
- Quantitative tests available
- Fewer stool specimens needed
Colon Check will use a quantitative FIT with a threshold of 100 ng/mL of hemoglobin. This threshold will yield a sensitivity and specificity of approximately 88% and 90%, respectively, for detecting colorectal cancer1. Furthermore, the FIT is able to detect advanced adenomas with a sensitivity of approximately 55%1.
There are no dietary or medication restrictions while collecting stool specimens for the FIT which will assist participant uptake and test completion 2.
Considering the results from the three randomized, controlled guaiac FOBT colorectal cancer screening trials, a population-based screening program using the FIT should lead to a decrease in colorectal cancer mortality through earlier detection3-5 and incidence through identification and removal of adenomatous polyps6.
1. Levi Z, Rozen P, Hazazi R, Vilkin A, Waked A, Maoz E, Birkenfeld S, Leshno M, Niv Y. A quantitative immunochemical fecal occult blood test for colorectal neoplasia. Ann Intern Med 2007;146:244-55.
2. Cole SR, Young GP, Esterman A, Cadd B, Morcom J. A randomised trial of the impact of new faecal haemoglobin test technologies on population participation in screening for colorectal cancer. J Med Screen 2003;10:117-22.
3. Mandel JS, Bond JH, Church TR, Snover DC, Bradley GM, Schuman LM, Ederer F. Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study. N Engl J Med 1993;328:1365-71.
4. Kronborg O, Fenger C, Olsen J, Jorgensen OD, Sondergaard O. Randomised study of screening for colorectal cancer with faecal-occult-blood test. Lancet 1996;348:1467-71.
5. Hardcastle JD, Chamberlain JO, Robinson MH, Moss SM, Amar SS, Balfour TW, James PD, Mangham CM. Randomised controlled trial of faecal-occult-blood screening for colorectal cancer. Lancet 1996;348:1472-7.
6. Mandel JS, Church TR, Bond JH, Ederer F, Geisser MS, Mongin SJ, Snover DC, Schuman LM. The effect of fecal occult-blood screening on the incidence of colorectal cancer. N Engl J Med 2000;343:1603-7.