Quantitating the Occult

Physicians are faced all too frequently with middle-aged patients who present with vague abdominal problems or rectal bleeding and who on evaluation are found to have colon cancer. A discouraging proportion of these relatively young people already have local spread of the disease or metastases to the liver. Spurred on by such cases, many physicians encourage asymptomatic patients who are over 40 to undergo annual testing for occult blood in stool as part of a screening program, in the hope that colon cancers may be detected at an early, curable stage or that adenomatous polyps may be found and removed.