Faecal haemoglobin-based referral and investigation prioritisation is associated with colorectal cancer-specific survival in symptomatic patients: a retrospective observational study.

BACKGROUND: Current BSG/ACPGBI and NICE guidance recommends that faecal haemoglobin (f-Hb) ≥10 ug/g measured by faecal immunochemical test (FIT) in symptomatic patients should prompt referral through cancer prioritised diagnostic pathways. However, limited long term CRC outcome data exist. This study compared CRC specific survival (CSS) between patients by f-Hb concentration and referral priority in a large primary care f-Hb prioritised lower GI symptomatic pathway. METHODS: Retrospective single health board study of symptomatic patients submitting FIT in primary care, 2019-2022. CRC diagnoses up to 3 years after pathway entry, and CRC deaths (ICD10 18, 19, 20) to end 2024 were recorded from cancer audit and MCN datasets. Patients were grouped by f-Hb concentration and referral priority. Univariable and multivariable Cox regression estimated CSS. RESULT: Of 126,984 patients, 1453 (1%) were diagnosed with CRC within 3 years of f-Hb result or referral, of which 444 (31%) died due to CRC. At multivariable analysis, referral without FIT (HR 1.42, 95% CI 1.06-1.91), and f-Hb ≥10 ug/g diagnosed outwith CRC prioritised pathways (HR 1.47, 95% CI 1.03-2.10) were associated with worse CSS independent of TNM stage. CONCLUSION: Referral and investigation through cancer prioritised pathways guided by f-Hb concentration is safe in relation to CSS.