Local recurrence after EMR of nonpedunculated colorectal lesions occurs in 3 % of en bloc resections and 20 % of piecemeal resections. Piecemeal resection was the only independent risk factor for recurrence. As more than 90 % of recurrences are detected at 6 months after EMR, we propose that 6 months is the optimal initial follow-up interval.

Colonoscopy is the standard method for detection and removal of colorectal adenomas, the precursor lesions of most colorectal cancers [1 -4]. Despite being the most sensitive method, colonoscopy does not fully protect a person from developing future colorectal cancer [5 -10]. This imperfection is for a major part caused by missed precancerous lesions due to inadequate bowel preparation, the presence of flat lesions that are difficult to detect [8,9,11], and the relative difficulty of visualizing lesions on the proximal side of haustral folds and the internal curves of flexures [12,13]. The latter may, at least partly, be caused by the fact that the use of standard 140°and 170°colonoscopes allows visualization of only approximately 90 % of the colonic surface [14]. Moreover, it has been shown that up to twothirds of missed lesions are located on the proximal side of folds [13]. The miss rates of colonoscopy have been widely acknowledged, with back-to-back colonoscopy studies showing polyp and adenoma miss rates of approximately 20 % -25 % in older studies [15] and up to 40 % in more recent studies evaluating novel technologies developed to improve visualization behind folds [16,17]. Alongside the implementation of quality indicators [1,18], technologies such as cap-assisted colonoscopy, virtual chromoendoscopy, Third Eye colonoscopy, and Full Spectrum Endoscopy (Fuse) colonoscopy have been developed to improve adenoma detection [16,17,19,20]. However, some of these techniques have been shown to increase only marginally the detection of adenomas, while others are less practical in use or demand high investments with a change in endoscopy platform [21,22]. Background and study aims: Adenoma miss rate during colonoscopy has become a widely acknowledged proxy measure for post-colonoscopy colorectal cancer. Among other reasons, this can happen because of inadequate visualization of the proximal aspects of colonic folds and flexures. EndoRings (EndoAid Ltd., Caesarea, Israel) is a silicone-rubber device that is fitted onto the distal end of the colonoscope. Its flexible circular rings engage and mechanically stretch colonic folds during withdrawal. The primary aim of this study was to compare adenoma miss rates between standard colonoscopy and colonoscopy using EndoRings. Methods: In this multicenter, randomized, tandem colonoscopy study, we performed same-day, back-to-back colonoscopies with EndoRings followed by standard colonoscopy, or vice versa. Results: After exclusion of 10 patients for protocol violations, 116 patients (38.8 % female; mean age 58.7) remained for analysis. The adenoma miss

Based on a population analysis of patients diagnosed with T1 CRC, additional surgery after endoscopic resection should be considered only for patients with high-risk histology or a positive resection margin.

Original article 703Introduction ! Screening strategies that employ colonoscopy for the detection and removal of precursors of colorectal cancer (CRC) effectively reduce CRC-related mortality [1,2]. Apart from participation grades, the efficacy of population-based CRC screening depends on the quality of colonoscopy. Colonoscopy quality is ultimately reflected by a reduction in the incidence of CRC following colonoscopy. However, measurement of post-colonoscopy CRC is cumbersome and does not allow direct feedback. Several procedural indicators have been suggested for the monitoring of quality [3]. Two recent studies showed that the adenoma detection rate (ADR) of endoscopists was inversely associated with the risk of post-colonoscopy CRC [4,5] and related death [5]. In another study, patients dying from CRC were less likely to have undergone a previous complete colonoscopy than matched controls [6]. In addition, a substantial proportion of colorectal tumors originate from the right-sided colon [7], which underlines the importance of performing a complete colonoscopy, as measured by the cecal intubation rate (CIR). ADR and CIR have been reported to vary between hospitals depending on case mix and institutional or procedural factors [8 -10]. Case mix is determined by nonmodifiable patient characteristics, such as age, sex, co-morbidity, and indication for colonoscopy. In order to provide a useful incentive for hospitals to improve the quality of colonoscopy, a comparison of CIR and ADR between institutions should enable detection of differences that are independently affected by modifiable * The first two authors contributed equally to the work. ** Both senior authors contributed equally to the work. Background and study aims: Cecal intubation rate (CIR) and adenoma detection rate (ADR) have been found to be inversely associated with the occurrence of post-colonoscopy colorectal cancer. Depicting differences in CIR and ADR between hospitals could provide incentives for quality improvement. The aim of this study was to compare quality parameters of routine colonoscopies between seven hospitals in The Netherlands in order to determine the extent to which possible differences were attributable to procedural and institutional factors. Patients and methods: Consecutive patients undergoing colonoscopy were prospectively included between November 2012 and January 2013 at two academic and five nonacademic hospitals. Patients with inflammatory bowel disease or hereditary colorectal cancer syndromes were excluded. Main outcome measures were CIR and ADR. Results: A total of 3129 patients were included (mean age 59 ± 15 years; 45.5 % male). The major- Belderbos

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