Should patients with anemia and low normal or normal serum ferritin levels undergo colonoscopy?

Colon malignancy is no more likely in patients with anemia and a serum ferritin level of greater than 100 ng/mL than it is in the general population. However, anemic patients with a serum ferritin level of less than 100 ng/mL may benefit from colonoscopy since they have a significantly increased risk of advanced polyps or cancer. (LOE = 2b)

Sawhney MS, Lipato T, Nelson DB, Lederle FA, Rector TS, Bond JH. Should patients with anemia and low normal or normal serum ferritin undergo colonoscopy? Am J Gastroenterol 2007;102:82-88.  [PMID:17037988]

Cross-sectional

Industry

Outpatient (specialty)

For adults with unexplained anemia and low serum ferritin levels, colonoscopy is usually recommended to exclude malignancy. Previous studies have shown that anemic patients with a serum ferritin level of less than 50 ng/mL have a significantly increased risk of colorectal cancer (CRC). This study looked at a broader range of patients with unexplained anemia, including those with a low normal and normal ferritin levels, to determine whether the risk of CRC was increased in these groups, as well. The authors reviewed an existing database of patients (mostly men) referred to a Veterans Administration Medical Center for colonoscopy between 1997 and 2004. Anemia was defined as a hemoglobin level of less than 13 g/dL for men and less than 12 g/dL for women. Those patients with evidence of gastrointestinal bleeding; colon cancer, or risk factors for colon cancer; or inflammatory bowel disease were excluded to identify a group with anemia but no obvious gastrointestinal cause or risk for colon malignancy. Only those patients whose serum ferritin level had been measured at the time of colonoscopy were included. They identified 424 anemic patients, 254 with serum ferritin levels of less than 50 ng/mL, 55 with serum ferritin between 50 and 100 ng/mL, and 115 with serum ferritin greater than 100 ng/mL. The researchers also compared these anemic patients with 323 nonanemic individuals referred for routine screening. The primary outcome was the percentage with advanced colonic neoplasia, which included CRC, malignant polyp, or polyp with high-grade dysplasia. This was found in 7.9% of those with serum ferritin levels of less than 50 ng/mL, 7.3% with ferritin between 50 and 100 ng/mL, but only 1.7% with ferritin levels greater than 100 ng/mL and 1.2% in the screening population. Similarly, CRC was found in 6.3% with serum ferritin levels of less than 50 ng/ml, 2.3% with ferritin between 50 and 100 ng/mL, but only 0.9% with a ferritin greater than 100 ng/mL and 0.6% in the screening population.