PTH-040 Positive faecal occult blood testing and negative screening colonoscopy: four year outcomes

Introduction The Bowel Cancer Screening Programme (BCSP) uses the faecal occult blood test (FOBT) to identify patients who may benefit from colonoscopy to exclude serious, usually asymptomatic pathology. If no polyps are detected, the patient is returned to the screening programme without further investigation. Method A retrospective cohort study was undertaken to elucidate the final diagnosis of all patients in the East Kent Hospitals screening programme in 2012 with a positive FOBT but no polyps or tumours detected at colonoscopy. The details of all patients were reviewed to determine which further investigations had been performed over a four-year period up to 31 December 2016. Data collected included: reported findings at index colonoscopy, histology if biopsies had been taken, results of subsequent colonoscopy or gastroscopy, CT, ultrasound and MRI scans. Results were obtained via the computerised patient records (endoscopy reports, patient letters, pathology viewer and PACS system). Patients with confirmed adenomatous polyps, tumours or those with incomplete procedures at index colonoscopy were excluded. Data were collated using Microsoft Excel 2016 and analysed using SPSS v15.0. Results Of the 621 patients that underwent a colonoscopy under the BCSP in 2012, 205 fulfilled the aforementioned criteria and were included in analysis. The median age was 64 years (range 60–86). Fifty-three (25.9%) colonoscopies were normal and 123 (60%) demonstrated only diverticular disease or haemorrhoids. Ten (4.9%) had definite endoscopic and histological evidence of inflammatory bowel disease (IBD) and 11 (5.4%) had non-specific endoscopic features such as erythema or mucosal oedema but without significant histological abnormality. Seven (3.4%) patients had colonic telangiectasia and one (0.5%) had ileitis. Of those patients with diverticulosis, haemorrhoids or a normal index colonoscopy, one was subsequently diagnosed with microscopic colitis and one with proctitis; 11 (6.3%) had polyps on subsequent colonoscopy of which one demonstrated evidence of mixed low and high grade dysplasia. This individual subsequently underwent left hemicolectomy for confirmed adenocarcinoma. Twelve patients (6.8%) were found to have upper gastrointestinal (UGI) pathology including gastric polyps, oesophagitis, gastritis, duodenitis, telangiectasias or duodenal ulceration. Imaging modalities reviewed were non-contributory in establishing the final diagnosis. Conclusion This study confirms that patients with a positive FOBT but negative colonoscopy should be strongly encouraged to continue in the screening programme as serious ‘missed’ pathology may subsequently be confirmed. Many patients with a negative screening colonoscopy underwent additional investigation in the four years following their index procedure, which in a small percentage of cases identified significant UGI pathology. Disclosure of Interest None Declared