The NHS BCSP provides high-quality colonoscopy, as demonstrated by high caecal intubation rate, ADR and comfort scores, and low adverse event rates. Quality is achieved by ensuring BCSP colonoscopists meet a high standard before starting screening and through ongoing quality assurance. Measuring total adenoma detection (MAP and MAP+) as adjuncts to ADR may further enhance quality assurance.

This study demonstrates that longer mean withdrawal times are associated with increasing adenoma detection, mainly of small or right-sided adenomas. However, beyond 10 minutes the increase in ADR is minimal. Mean withdrawal times longer than 6 minutes are not associated with increased detection of advanced adenomas. Withdrawal time remains an important quality metric of colonoscopy.

Introduction !Colorectal cancer (CRC) is the second most common cause of cancer death in the United Kingdom [1]. The majority of CRCs develop from adenomas [2]. Adenoma detection is therefore a key objective of colonoscopy. Adenoma detection rate (ADR) is widely regarded as one of the key performance indicators of colonoscopy [3]. Increasing ADR has been shown to correlate with decreased interval cancer rate [4]. Multiple factors may affect whether an adenoma is detected during colonoscopy. These may be patient factors such as male sex, increasing age, cigarette smoking, and alcohol use [5 -9]. This study focused on the colonoscopy factors (many of which relate to the completeness of pancolonic mucosal inspection) that determine whether adenomas are detected. Cecal intubation, colonoscopy withdrawal time, and bowel preparation quality have been shown to be associated with increased adenoma detection [10 -16]. Other technical factors, such as intravenous antispasmodic use, rectal retroversion, start time of the procedure, and sedation practice, have been postulated as affecting adenoma detection with conflicting findings in studies to date [17 -26]. These factors are important as they are modifiable by the colonoscopist, offering the opportunity to optimize adenoma detection, and may reduce future cancer risk. Background and study aims: Adenoma detection is a key objective of colonoscopy, particularly in the context of colorectal cancer screening. The aim of this observational study was to identify the technical colonoscopy factors associated with adenoma detection. Patients and methods: The study analyzed data from the English Bowel Cancer Screening Programme. The indication for all colonoscopies was a positive fecal occult blood test. The relationships between the following colonoscopy factors and adenoma detection (one or more adenomas, advanced adenomas, right-sided adenomas, and total number of adenomas) were examined in multivariable analyses: bowel preparation quality, cecal intubation, withdrawal time, rectal retroversion, colonoscopist experience, antispasmodic use, sedation use, and start time of procedure. The following patient factors were controlled for: age, sex, body mass index, smoking, alcohol, deprivation, and geographical location.