Colon cancer is the 2nd leading cause of cancer deaths in North America. So far nothing we have done in terms of prevention has helped decrease the rates of colon cancer. The only way to improve mortality is to make a diagnosis of the cancer early. We do have many screening tests for colon cancer, but tests like colonoscopy and virtual colonoscopy are expensive. The Fecal occult blood test is not very specific.
In the last few years, scientists have developed Fecal DNA tests. The first generation of these tests were not great. For example, the tests would repeatedly show that you have a cancer, when in fact you did not have a cancer (false positives). Further, the tests also sometimes showed that one did not have a cancer, when in fact a cancer was present (false negative). However, the latest generation of DNA tests have been improved but they are not 100 percent sensitive or specific.
The tests involving sampling stool for DNA. A colon cancer if present anywhere in the colon can be identified roughly 88% of the time.
The Fecal DNA kits appear to be slightly better than the fecal occult blood test kits (FOBT) at detecting colon cancer.
For the time being, anyone over the age of 50, should continue with a reliable screening test for colon cancer. The fecal DNA tests will most likely be improved in the future but for the time being, the fecal occult blood test should not be chucked away. Cost is another issue. The Fecal occult blood tests can cost anywhere from $3-$25, while the DNA kits costs anywhere from $500-$1,000. Another big difference is that the FOBT only requires a stool smear; the DNA kits require collecting a whole bucket of stools.
And finally, the majority of insurance carriers do not cover costs of the Fecal DNA test. For the time being and for those who can afford it, Colonoscopy is still the gold standard screening test for colon cancer.
