Routes to Diagnosis and Stage at Diagnosis of Colorectal Cancer in Patients Aged ≥ 50 Years: A Multicentre Retrospective Cohort Study From North Wales, UK

'Route to diagnosis', the clinical pathway through which a cancer is first identified, is associated with stage at presentation in colorectal cancer (CRC), but recent regional data in the UK describing this relationship following the wider adoption of symptomatic faecal immunochemical testing (FIT) is limited. This study describes contemporary routes to diagnosis among patients aged ≥ 50 years with CRC in a single Welsh health board and compares unadjusted stage distribution between routes. A retrospective cohort study was conducted across three secondary care sites within Betsi Cadwaladr University Health Board, North Wales, including patients aged ≥ 50 years with newly diagnosed primary colorectal cancer between 1 January 2023 and 31 December 2024. Routes were Bowel Screening Wales (BSW), asymptomatic FIT, symptomatic FIT, symptoms only, emergency presentation, and incidental detection. Stage was the pre-treatment tumour, node, and metastasis (TNM) stage where available; otherwise, pathological stage. Stage was compared across routes using Pearson's chi-square test, with four pre-specified pairwise comparisons of advanced-stage (III-IV) disease. The asymptomatic FIT group was described only. Of 976 patients, two (0.2%) were diagnosed via asymptomatic FIT. Among the remaining 974, symptomatic FIT was the most common route (506, 52.0%), followed by BSW (172, 17.7%), symptoms only (131, 13.4%), emergency presentation (112, 11.5%), and incidental detection (53, 5.4%). Overall, 515/974 (52.9%) had advanced-stage disease, and stage differed by route (p < 0.001). Advanced disease was lowest in BSW (37.8%), intermediate in symptomatic FIT (51.8%), higher in symptoms-only (60.3%) and emergency (60.7%) diagnoses, and highest in incidental diagnoses (77.4%). Compared with BSW, the proportion with advanced disease was 22.9 percentage points higher in emergency presentations (95% CI 11.3-34.5) and 39.6 points higher in incidental diagnoses (95% CI 26.2-53.0). The difference between symptomatic FIT and emergency presentations (8.9 points, 95% CI -1.1 to 19.0) was not statistically significant. In this unadjusted analysis, which may partly reflect differences in age, tumour location and staging method, screening-detected cancers had the lowest proportion of advanced disease and incidental diagnoses the highest. Just over half of cancers diagnosed after a positive symptomatic FIT were stage III-IV; as only diagnosed patients were included, this does not assess FIT effectiveness. These findings provide a regional benchmark and identify pathways where the reasons for late-stage diagnosis warrant further investigation.