Serum ferritin and stool occult blood and colon cancer screening.

A group of 531 participants age 50 years or older were evaluated for colonic polyps and malignancy with stool occult blood testing, hemoglobin, hematocrit, serum ferritin, flexible fiberoptic sigmoidoscopy, and colonoscopy. Screening revealed 1 colorectal cancer, 2 malignant polyps, 30 hyperplastic polyps, 69 adenomatous polyps, 4 villous adenomas, and 2 villous components. Low serum ferritin, an indicator of iron deficiency without anemia, improved the detection of colonic malignancies and polyps when used in combination with stool occult blood testing. The program was acceptable to participants and attrition was low; the attrition rate for the screening program at 1 year was 14.5%.