Abstract
Background
In primary care, NICE 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-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 one-year CRC risk by patient age, f-Hb result and presence of IDA.
Results
Of 34647 valid f-Hb results retrieved; 7889 (22.8%) had f-Hb ≥10µg Hb/g. Of these, 33285 samples (96.1%) had associated FBC results of which 3000 (9.0%) had IDA. Overall, 571 incident CRC were recorded. Risk of CRC breached 3% in patients with f-Hb >99µg Hb/g aged >40 years and reached 30% (19.4-41.0) with f-Hb >99µg 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 iron deficient anaemia (IDA) status improves CRC risk prediction, identifies a low-risk group with f-Hb<20µg Hb/g and no IDA, and could inform revised referral guidance.
In primary care, NICE 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-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 one-year CRC risk by patient age, f-Hb result and presence of IDA.
Results
Of 34647 valid f-Hb results retrieved; 7889 (22.8%) had f-Hb ≥10µg Hb/g. Of these, 33285 samples (96.1%) had associated FBC results of which 3000 (9.0%) had IDA. Overall, 571 incident CRC were recorded. Risk of CRC breached 3% in patients with f-Hb >99µg Hb/g aged >40 years and reached 30% (19.4-41.0) with f-Hb >99µg 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 iron deficient anaemia (IDA) status improves CRC risk prediction, identifies a low-risk group with f-Hb<20µg Hb/g and no IDA, and could inform revised referral guidance.
| Original language | English |
|---|---|
| Number of pages | 7 |
| Journal | Gut |
| DOIs | |
| Publication status | Published - 26 Mar 2025 |
Keywords
- bowel disease
- colorectal cancer
- faecal biomarkers
- faecal immunochemical test
- faecal haemoglobin
- full blood count
- age
- primary care
