Are hemoglobin levels really lower in faecal immunochemical test positive patients with colorectal cancer?

Abstract

IntroductionFaecal immunochemical test (FIT) is advocated in many colorectal cancer-screening programs. A positive FIT translates to the need for a colonoscopy. However, waiting times for diagnostic colonoscopy is long. The aim of our study is to determine the correlation of hemoglobin levels in patients with a positive FIT who were subsequently diagnosed with colorectal cancer, and to compare them with patients with only colonic adenomas and those with normal colonoscopy with the intention of determining if hemoglobin levels could be used to stratify the urgency of colonoscopy. MethodologyThis is a matched case–control study of patients who were FIT positive and subsequently underwent colonoscopy at the National University Hospital, Singapore. Newly diagnosed colorectal cancers formed the case group. The patients with colorectal cancers were then matched for age, gender and ethnicity at a 1:1 ratio to patients with colonic adenomas and then those in whom colonoscopy was normal. ResultsFifteen patients met the inclusion criteria and formed the case group. The differences between the groups were not statistically significant in terms of age, gender and ethnicity. The median hemoglobin level for the patients in the case group compared to the control group was (12.4 vs 14.5, p = 0.002) for the group with adenomas and (12.4 vs 14.4, p = 0.007) for the group with normal colonoscopy. ConclusionColorectal cancer patients presenting with a positive FIT are more likely to be anemic. A test to identify those patients who have a positive FIT that are anemic could enable earlier colonoscopic evaluation.