Serum ferritin and risk of colonic neoplasia: Implications for the workup and treatment of iron deficiency

Iron deficiency is the most common extraintestinal sign of colonic neoplasia, including colorectal cancer (CRC) and other lower gastrointestinal pathology. Both upper endoscopy and colonoscopy is usually recommended in the work-up of patients with unexplained iron deficiency, particularly in men and postmenopausal women. As the incidence of early-onset CRC (age <50 years) rises in the United States, there is an increasing need to identify risk predictors to aid in the early detection of CRC. It remains unknown if serum ferritin (SF), and what specific threshold, can be used as a marker to stratify those at risk for CRC and other lower gastrointestinal pathology. In this current review of the literature, we aimed to review guidelines for diagnostic workup of colonic neoplasia in the setting of iron deficiency and examine the association and specific thresholds of SF and risk of CRC by age. Some of the published findings are conflicting, and conclusions specific to younger patients are limited. Though further investigation is warranted, the cumulative findings suggest that SF, in addition to considering the clinical context and screening guidelines, may have potential utility in the assessment of colonic neoplasia.