Combining faecal haemoglobin, iron deficiency anaemia status and age can improve colorectal cancer risk prediction in patients attending primary care with bowel symptoms: a retrospective observational study
Menée à partir de données portant sur 33 295 patients présentant des symptômes intestinaux et à partir de données du registre écossais des cancers, cette étude met en évidence l'intérêt d'utiliser la concentration d'hémoglobine dans les selles, la présence d'une anémie ferriprive et l'âge pour prédire le risque de cancer colorectal
Background : In primary care, National Institute for Health and Care Excellence suspected cancer guidelines recommend measuring faecal haemoglobin (f-Hb) if colorectal cancer (CRC) is suspected, with a referral threshold of ≥10 µg Hb/g faeces defining a 3% risk, but most have a normal colonoscopy.
Objective : Examine whether combining f-Hb, patient age and iron-deficient anaemia (IDA) status improves risk prediction.
Design : Retrospective single-centre observational study of symptomatic patients who submitted contemporaneous f-Hb and full blood count (FBC) samples between December 2015 and December 2019. f-Hb was estimated using HM-JACKarc (Hitachi Chemical Diagnostics Systems). Patients were categorised by presence/absence of IDA. Incident CRC was identified via record linkage to the Scottish Cancer Registry. Kaplan-Meier estimates determined cumulative 1-year CRC risk by patient age, f-Hb result and presence of IDA.
Results : Of 34 647 valid f-Hb results retrieved; 7889 (22.8%) had f-Hb≥10 µg Hb/g. Of these, 33 285 samples (96.1%) had associated FBC results of which 3000 (9.0%) had IDA. Overall, 571 incident CRC were recorded. The risk of CRC breached 3% in patients with f-Hb>99 µg Hb/g aged >40 years and reached 30% (19.4–41.0) with f-Hb>99 µg Hb/g in age >55 years plus IDA. 2029 f-Hb results (25.7%) were in the 10–19 µg Hb/g range of which 27 (1.3%) had CRC. In this subgroup, CRC risk did not exceed 3% in patients <85 years and no IDA.
Conclusion : Combining f-Hb, patient age and IDA status improves CRC risk prediction, identifies a low-risk group with f-Hb<20 µg Hb/g and no IDA and could inform revised referral guidance.
Gut , article en libre accès, 2025