A Retrospective Review of the Secondary-care Colorectal Cancer Pathway Within NHS Lothian: An Evaluation of 3 Years of Pathway Performance

Bowel cancer (colorectal cancer) is the 4th most common cancer in Scotland. Approximately 4,000 cases are diagnosed annually. Cancer-related deaths in Scotland are higher than other UK nations. Improving the early detection of bowel cancer, and therefore survival, is important.

The majority of bowel cancers are diagnosed within secondary-care (colorectal surgery unit). Upon GP referral to secondary-care, patients provide stool samples which are analysed for microscopic blood (FIT; faecal immunohistochemical test). Patients with a single positive result are more likely to have bowel cancer (0.2% risk if no blood detected, but 8.4% if detected). A positive test triggers further investigation, either CT scan or colonoscopy depending on the result. Currently, colonoscopy and radiology services throughout Scotland are under significant pressure causing delays.

Only 2% of patients referred to secondary-care are diagnosed with bowel cancer, and most colonoscopies performed do not yield significant findings. We have shown that performing two repeated FITs upon referral improves cancer pickup rate (sensitivity) and reduces missed cancers. We successfully implemented this in NHS Lothian and contributed to national guidelines.

This study will undertake a comprehensive retrospective review of the double-FIT urgent suspicion of bowel cancer pathway within NHS Lothian, from April 2022 (date of pathway inception) to August 2025, including around 25,000 patients that have been managed through the pathway. We will calculate key performance indicators and diagnostic accuracy of the pathway. Health economic analysis will determine cost-per-diagnosis. Risk factors for bowel cancer in this patient cohort will be identified to develop a support tool for primary and secondary-care. These results will be used to develop a future pathway to optimise pathway efficiency and cancer detection.