Single-sample colorectal cancer test faulted by study

Colorectal cancer screening is effective, but not the single-stool blood test that is all too frequently performed in physicians' offices.

By Susan J. Landers, AMNews staff. Feb. 14, 2005.

Washington -- Sometimes the tried and true turns out to be neither. This is the case with physicians using a single-sample fecal occult blood test done in their office to screen for colorectal cancer.

The method is a poor screening tool, missing about 95% of precancerous advanced lesions, according to a study published in the Jan. 18 Annals of Internal Medicine. And a second study, also published in the Jan. 18 Annals, found that nearly one-third of primary care physicians surveyed who use the FOBT rely only on the single-sample office method to screen for colorectal cancer.

The American Gastroenterological Assn., for one, would like to change that.

Given that colorectal cancer is second only to lung cancer as the leading cause of cancer-related death in the United States, and that the transformation from benign colon polyps to invasive malignancy takes place over several years, early detection is key to reducing the high mortality rate.

Several recommended screening methods could help bring it down. Although the single-sample test is not among them, it still holds a place in the annual physical, especially for men older than age 50, said Emmet B. Keeffe, MD, AGA president.

Physicians often resort to the test because of poor compliance with the more accurate six-sample fecal occult blood test completed at home by patients. The thought is that one test is better than none.

However, the new study "really puts aside a standard procedure that we had learned was appropriate to do as part of a routine patient evaluation," said Dr. Keeffe.