Stop Colorectal Cancer Through Prevention and Screening
In the Capital Health Region, 18.6% of colorectal cancers are detected at stage 1, while
22.4% are already at stage IV. The Capital Health Region has 340,000 individuals aged
50-74, yet only 14.3% receive any colorectal cancer screening. These low screening rates
may be attributed to lack of awareness, the limitations of the fecal occult blood testing
(FOBT) and the unpleasant associations with both the FOBT and the colonoscopy. The
limitations of the FOBT include low sensitivity for detection of adenomas and small cancers,
the cumbersome method of stool collection on multiple days and the dietary restrictions,
which make patient compliance low and introduce high probability of false positive tests and
Currently, there are two screening modalities available. The fecal occult blood testing
(FOBT: Hemoccult II) detects blood in the stool that may be due to colonic adenomas or
cancer. The second is colonoscopy, which is the gold standard in detecting colorectal
lesions; however it carries the risks of bleeding and bowel perforation. FOBT is the
recommended primary screening tool for patients at average risk for developing colorectal
cancer. Large population-based randomized controlled trials have consistently demonstrated
a significant survival benefit in patients who undergo annual or biannual screening with
Recently, newer generation FOBT techniques, the FOBT immunochemical (FIT) has become
available. These tests are more sensitive in detecting specifically human blood in the
stool and do not require dietary restrictions. Recent studies have suggested the diagnostic
performance of the FIT may be superior to standard Hemoccult II rates because of simplified
sampling. As well, economic analysis have suggest that the use of FIT is superior to FOBT
in diagnostic performance at a reasonable cost to a European population.
A urine specimen will also be obtained and analyzed for metabolomics for each subject.
Metabolomics is the study of the global chemical composition of an organism. It utilizes
technologies such as a nuclear magnetic resonance spectroscopy to study the metabolite /
chemical composition, interactions, and changes in these levels in response to disease or
environmental factors. By analyzing urine samples, it has been possible to identify the
metabolite patterns characteristic of various diseases. In addition, the metabolite patterns
of liver disease caused by cirrhosis and hepatitis, inflammatory bowel disease and cancer
have been identified. Urine metabolomics analysis may offer a new sensitive, yet
inexpensive screening tool for colorectal cancer.
Observational Model: Cohort, Time Perspective: Prospective
Compare the diagnostic performance characteristics of the guaiac based Hemoccult II FOBT and two FIT's, the Hemoccult ICT and MagStream HemSp, using colonoscopy as the gold standard.
FOBT, FIT (Hemoccult ICT) and MagStream Hemsp will be obtained prior to colonoscopy.
Daniel C Sadowski, MD
Royal Alexandra Hospital
Canada: Ethics Review Committee