Given the benefits of early detection and diagnosis, it is recommended that people over 50 get tested regularly for signs of colon cancer, which is the second leading cause of cancer deaths in the United States. Unfortunately, the testing is often unpleasant, invasive, and time-consuming. The best way to detect colon cancer is with a colonoscopy, a difficult. involved, and costly procedure that generally involves giving the patient anesthesia.
Now doctors may soon have a less unpleasant, less intrusive way of looking for colon cancer. The technique involves looking at a blood sample for certain genetic changes that are indicative of the presence of cancer. Called methylation, the change is found far more frequently in tumor cells than in healthy tissue, and its presence appears to be a largely—thought not entirely—reliable indicator of whether someone has cancer or a per-cancerous condition likely to develop into cancer.
Blood tests are already part of the diagnostic process. The current use of blood tests is to looking for signs of organs not working properly. However, by that time the cancer may be quite advanced already and far less tractable than if it had been caught sooner.
This is good news for people at risk for colon cancer. Age is probably the biggest risk factor: 90 percent of cases are in people over 50. African Americans are also particularly vulnerable to the condition. As with many forms of cancer, a family history of the condition is a sign you’re likely to get it yourself. People with other diseases of the colon tend to be likely to get cancer as well, are are people who are out of shape, who smoke, and who lead generally sedentary lives.
In addition to colonoscopy, current diagnostic techniques include what is called a complete blood count, measuring the amount of iron in the blood. Serious illnesses, particularly involving digestion, are often associate with anemia. Imaging procedures may also be used that are less direct then colonoscopy, but these also are less exact and less reliable. For example, patients may be X-rated after drinking contrast die, a substance that shows up on X-rays, allowing the colon to be outlined and delineated. CAT scan images—with or without a contrast—can also be used to create what is called a virtual colonoscopy, providing almost as good a look as the genuine article.