Over 150,000 cases of Colon Cancer occur each year in the US. Somewhere between 15 to 20% of these decidedly have a genetic basis; that is, an inherited defective or abnormal gene is responsible for the disease developing (for example the gene responsible for Familial Polyposis). There are many things we can do to decrease our risk of Cancer, but when we're stuck with an abnormal Gene-what can we do?
One way to improve the odds, would be to find out who has the abnormal gene, and use exams that could prevent the cancer before it occurs. Colon cancer is an excellent model for this method of prevention, because in most cases, the cancer develops over many years from abnormal though benign growths known as Polyps. In the Familial Polyposis Syndrome, hundreds of polyps develop, with at least one developing into cancer (no longer benign) at the age of 30 or so.
Recently, another gene that leads to another form of Hereditary Colon Cancer has been identified. The abnormal gene is found in about 5% of Ashkenazai Jews; those who carry the gene have a 30% risk of developing Colon Cancer. Why some do and some don't develop cancer-is still not understood. We do know that in most instances, cancer develops only thru a series of genetic changes. Some of these may be caused by our environment; perhaps ingesting less "carcinogenic" foods, might save some of us.
Because Colon Cancer is so frequent in the US population, many
physicians have suggested "screening" all individuals
over a certain age, by means of an endoscopic exam called Colonoscopy.
This exam can find colon polyps and remove them before they develop
into cancer. As we develop more genetic tests, we will hopefully
be able to identify those with the greatest risk, and examine
them at an earlier age, when the cancer may be preventable.
For more, please visit the MedicineNet.com Colon Cancer Center.