Anaemia as a risk stratification tool for symptomatic patients referred via the two-week wait pathway for colorectal cancer.

Introduction Anaemia is associated with cancer. In 2014 a new form was introduced in our department requesting a haemoglobin (Hb) result on every two-week wait referral for suspected colorectal cancer (CRC). The aim of this study was to review the impact of this intervention. In particular, the significance of any evidence of anaemia (without additional indices) was investigated. Methods A review was conducted of 1,500 consecutive suspected CRC referrals recorded prospectively over a 10-month period. Data on demographics, referral Hb, referral criteria and outcomes were analysed. Anaemia was defined according to World Health Organization criteria (Hb <120g/l for women, Hb <130g/l for men). Results Overall, 1,015 patients were eligible for inclusion in the study. Over a third (38.2%) were documented as anaemic on referral. These patients were three times more likely to be diagnosed with CRC than non-anaemic patients (odds ratio [OR]: 3.22, 95% confidence interval [CI]: 1.87-5.57). Using a more stringent threshold (Hb <100g/l for women and <110g/l for men), they were four times more likely to have CRC (OR: 4.27, 95% CI: 2.35-7.75). Almost a quarter (23.7%) were actually anaemic at the time of referral but not referred with anaemia. In this subgroup, there was a 2.8-fold increase in risk of CRC diagnosis compared with non-anaemic patients (adjusted OR: 2.77, 95% CI: 1.55-4.95). Conclusions Nearly a quarter of patients not referred with iron deficiency anaemia had evidence of anaemia and this was still associated with a higher rate of CRC detection. A full blood count alone might help to risk stratify symptoms such as change in bowel habit in patients on urgent pathways and identify those cases most likely to benefit from invasive investigation.