Introduction Patients with a positive faecal occult blood test as a part of the Bowel Cancer Screening Programme (BCSP) are offered colonoscopy or if unsuitable for colonoscopy, an alternative radiological colonic examination (barium enema, BE; CT colonography, CTC; abdominal CT). However, there are no guidelines recommending which patients should be offered an alternative radiological test and no published data about current practice. The aim of this study was to review the demographics and outcomes of patients who underwent radiological screening investigation.

Methods Patient data are prospectively collected for each BCSP episode and collated at the central office. We retrospectively reviewed data recorded for patients who underwent radiological investigation as part of BCSP from the start of the programme to November 2008. Patient demographics and outcomes were evaluated. Categorical variables were compared using Fisher's exact test.

Results There were 440 patients (mean age 66 years, SD 3.9) who underwent 446 radiological investigations (Barium enema, BE: n=120, CT colonography, CTC: n=264, abdominal CT: n=54, AXR: n=8). There is wide geographical variation in choice of radiological investigation across England (Abstract 025).

Patients' mean ASA status was 2.5 (SD 0.8) and 43/440 (10%) were diabetic, 86/440 (20%) were taking warfarin and 47/440 (11%) clopidogrel. The indications for radiological investigation were documented for 370/440 (84%) patients—unsuitable for colonoscopy, n=213 (58%), incomplete colonoscopy, n=60 (16%), patient preference, n=54 (15%) and consultant preference, n=38 (10%). Eight cancers were diagnosed by a primary radiological investigation and there were 176 (39%) normal investigations (50/120, 42% vs 126/264, 48%, p=0.32 for BE and CTC, respectively). In 16 cases (4%; 3/120 vs 13/264, p=0.41 for barium enema and CTC, respectively) another test was required due to incomplete test (9 due to poor bowel preparation) and in 123 of cases (30%; BE 24/120, 20% vs CTC 99/264, 38%, p<0.001) a test was completed but an another investigation was required (therapy, n=52 and biopsies, n=59).

Conclusion There is a difference across the BCSP in the choice of radiological investigation offered to patients. Overall, 40% of patients having radiological investigation avoid further invasive endoscopic investigation with bowel preparation. More patients who have CTC require further investigation compared to BE, likely reflecting the greater sensitivity of the former.