Introduction Patients with a positive faecal occult blood test invited for screening colonoscopy may have undergone previous colonoscopy. Excluding such patients from a repeat colonoscopy may reduce endoscopy waiting lists and avoid repeated and unnecessary invasive investigations. This study investigates the prevalence of previous colonoscopy in Bowel Cancer Screening Programme (BCSP) patients and considers whether repeat colonoscopy is required.
Methods All patients undergoing BCSP colonoscopy over a 30-month period at our unit were identified and cross-referenced against colonoscopy records for the preceding 3 years. New diagnoses of colorectal cancer in the cohort were identified and cancer yield in those with and without recent colonoscopy compared using the chi-squared test.
Results 1419 BCSP colonoscopies were performed in 1339 patients over the study period. 109 colonoscopies were repeats with median interval to repeat 378 days. Indication for prior colonoscopy included prior BCSP invitation (n = 90), polyp surveillance (n = 6) and symptoms (n = 13). There were 111 diagnoses of colorectal cancer in the cohort but no patient with a previous colonoscopy was found to have colorectal cancer. Cancer yield in first time BCSP colonoscopy was greater than in repeated colonoscopy (8% vs. 0% p = 0.002).
Conclusion Cancer yield is reduced in BCSP patients with a recent negative colonoscopy. Excluding such patients would reduce pressure on endoscopy units and any morbidity associated with repeat colonoscopy. However, such an approach would be associated with a small risk of missed pathology. Larger studies are required to define the safety of this approach and inform national guidance.
Disclosure of Interest None Declared.