Iron deficiency anaemia and delayed diagnosis of colorectal cancer: a retrospective cohort study.

Aim  The extent to which different referral pathways following a primary care diagnosis of iron deficiency anaemia (IDA) are associated with delay to diagnosis of colorectal cancer (CRC) was determined.. Method  Eligible patients aged 40 or more years, with IDA diagnosed in primary care, and a subsequent diagnosis of CRC were studied retrospectively. Referral pathways were identified using the specialty of first recorded GP referral following IDA diagnosis. Differences in time to diagnosis of CRC were assessed by referral specialty. Differences in the proportion of cases referred before and after the re-issue of the NICE urgent referral guidelines for suspected lower gastrointestinal (GI) cancer were also assessed. Results  Of 628,882 eligible patients, 3.1% (n=19,349) were diagnosed with IDA during the study period. 3.0% (n=578) were subsequently diagnosed with CRC. 259 (44.8%) patients had no recorded referral or a referral unrelated to anaemia or the GI tract. Only 35%(n=201) of patients were referred to a relevant specialty. Median time to CRC diagnosis ranged from 2.5 months (referral to a relevant surgical specialty) to 31.9 months (haematology). Time to diagnosis was longer in patients referred to a medical compared with a relevant surgical specialty (p=0.024). There was no significant difference in time to CRC diagnosis before and after the NICE guidelines were re-issued in 2005. Conclusion  Significant differences exist between referral specialties in time to CRC diagnosis following a primary care diagnosis of IDA. Despite NICE referral recommendations, a significant proportion of patients are still not managed within recommended care pathways to CRC diagnosis.