SIGNIFICANCE OF SERUM IRON AND FERRITIN IN PATIENTS WITH COLORECTAL ADENOMAS

Background: Colorectal adenomas are often detected on mass screening, although detection rates with fecal occult blood tests are low. The re lationship between colorectal adenomas and the resulting blood loss wa s examined indirectly, using serum iron and ferritin levels. Methods: Serum iron and ferritin concentrations were measured in 184 men with c olorectal adenomas (greater than or equal to 1 cm in 92; <1 cm in 92) and in 92 healthy male controls. Values in the three groups were compa red. In the patients with adenomas greater than or equal to 1 cm, seru m iron and ferritin levels were compared on the basis of the site, num ber, histology, and degree of dysplasia of the adenoma. Results: The m ean serum iron level was significantly lower in patients with adenomas greater than or equal to 1 cm than in controls (P<0.05), although thi s level did not differ significantly between those with adenomas <1 cm and controls. The mean serum ferritin level also was significantly lo wer in patients with adenomas greater than or equal to 1 cm than in th ose with adenomas <1 cm and controls (P<0.05, P<0.01, respectively), a lthough this level did not differ between those with adenomas <1 cm an d controls. There was no difference in mean serum iron or ferritin lev els on the basis of the site, number, histology, or degree of dysplasi a of the adenoma. Conclusions: We conclude that decreased serum iron a nd ferritin levels are related only to adenoma size and that adenomas greater than or equal to 1 cm may bleed steadily, resulting in iron de ficiency. However, low dietary intake of iron and fiber may be one of the causes of low serum iron and ferritin.