What Proportion of Patients Referred to Secondary Care with Iron Deficiency Anemia Have Colon Cancer?

Purpose

Iron deficiency anemia can be the first presentation of right-sided colon cancer. There is an impression that because this presentation is nonspecific it may be associated with a longer delay from referral to diagnosis compared with those patients with symptoms of change in bowel habit and/or rectal bleeding caused by more distal colorectal cancer. This study was designed to determine the incidence of colon cancers in patients referred to the hospital with iron deficiency anemia and to determine what proportion of these patients were referred and diagnosed urgently in line with cancer waiting time targets.

Methods

A retrospective study was performed, including all patients referred to one district general hospital in 2003 whose blood indices met the criteria for significant iron deficiency anemia as defined by the Referral Guidelines for Suspected Cancer issued by the Department of Health in 1999, which defined iron deficiency anemia in the “target wait” criterion as a low hemoglobin (<11 g/dl in males and < 10 g/dl in postmenopausal females) with a mean corpuscular volume < 78 fl and/or a serum ferritin < 12 ng/ml. Patients with hemoglobinopathy were excluded. The underlying diagnosis reached for each patient was determined by using ICD10 C18–21. Case note review confirmed the diagnoses and yielded information on urgency of referral and time to diagnosis.

Results

Of 513 patients referred with iron deficiency anemia in 2003, 142 (28 percent) met the eligibility criteria. Nine (6.3 percent) of these had colon cancer, including one (1.2 percent) female and eight (14 percent) males. Eight of nine cancers were in the right colon. Other patients with iron deficiency anemia were found to have benign upper or lower gastrointestinal disease (n = 125) or upper gastrointestinal cancer (n = 1). In seven patients, no cause was found. Of the nine patients with iron deficiency anemia who were found to have colon cancer, five had been referred urgently and four as routine. The mean delay from referral to diagnosis for these was 31 days for those referred urgently but 60 days for those referred routinely.

Conclusions

Males referred with iron deficiency anemia have a significant risk of having colon cancer. The risk seems lower in females; this gender difference has been observed in other studies and further evidence should be sought before advising any change in referral practice.