PTU-037 Outcomes in patients who decline bowel cancer screening colonoscopy after positive faecal occult blood testing

Introduction The Bowel Cancer Screening Programme (BCSP) uses the faecal occult blood test (FOBT) to identify patients who may benefit from colonoscopy to rule out potentially serious usually asymptomatic pathology. Screening of asymptomatic FOBT positive patients enables early identification and removal of premalignant adenomatous polyps thereby significantly reducing risk of progression to colon cancer. Methods A retrospective cohort study design was employed in order to ascertain the final outcome in patients with a positive FOBT that had subsequently declined colonoscopy within the East Kent Hospitals screening programme. The records of all patients with screening appointments from January 2010 to December 2016 were reviewed in order to identify which further investigations had taken place up to 27 July 2017. Data were obtained from electronic patient records (endoscopy reports, patient letters, pathology viewer and PACS system) and included: results of subsequent colonoscopy or gastroscopy, CT, ultrasound and MRI scans, as well as histology obtained by any means. Data were collated using Microsoft Excel 2016 and analysed with SPSS v15.0. Results The present study included 376 patients that had declined colonoscopy. The median age was 66.6 y (range 59.8–91.4). Subsequent investigations were performed in 215 (57.2%) patients and identified possible explanatory abnormalities (table 1). The follow-up period for subsequent investigations ranged from 6 months to 7 years depending on whether patients were identified at the end or the beginning of the study period, respectively. Two of four upper gastrointestinal (UGI) cancers and 8 of 24 lower gastrointestinal (LGI) cancers were diagnosed in those with the longest follow-up (i.e. the 2010/11 cohort). Of the 161 patients (42.8%) without follow-up data, 21 (13.0%) had prior diagnoses that may have accounted for a positive FOBT (e.g. gastritis, polyps, telangiectasia etc.). Conclusions This study confirms that dissenters with positive FOBT should be encouraged to undergo colonoscopy as in this cohort, a significant proportion subsequently investigated outside of the BCSP will have or develop cancer. Many of the cancers identified were in those with the longest period of follow up, suggesting that the overall risk of potentially serious pathology in this study is likely to be significantly underestimated.