Margaret Vance

Optical diagnosis of small colorectal polyps at routine colonoscopy (Detect InSpect ChAracterise Resect and Discard; DISCARD trial): a prospective cohort study

BACKGROUND Accurate optical diagnosis of small (<10 mm) colorectal polyps in vivo, without formal histopathology, could make colonoscopy more efficient and cost effective. The aim of this study was to assess whether optical diagnosis of small polyps is feasible and safe in routine clinical practice. METHODS Consecutive patients with a positive faecal occult blood test or previous adenomas undergoing surveillance at St Marks Hospital (London, UK), from June 19, 2008, to June 16, 2009, were included in this prospective study. Four colonoscopists with different levels of experience predicted polyp histology using optical diagnosis with high-definition white light, followed by narrow-band imaging without magnification and chromoendoscopy, as required. The primary outcome was accuracy of polyp characterisation using optical diagnosis compared with histopathology, the current gold standard. Accuracy of optical diagnosis to predict the next surveillance interval was also assessed and compared with surveillance intervals predicted by current guidelines using histopathology. This study is registered with ClinicalTrials.gov, NCT00888771. FINDINGS 363 polyps smaller than 10 mm were detected in 130 patients, of which 278 polyps had both optical and histopathological diagnosis. By histology, 198 of these polyps were adenomas and 80 were non-neoplastic lesions (of which 62 were hyperplastic). Optical diagnosis accurately diagnosed 186 of 198 adenomas (sensitivity 0.94; 95% CI 0.90-0.97) and 55 of 62 hyperplastic polyps (specificity 0.89; 0.78-0.95), with an overall accuracy of 241 of 260 (0.93, 0.89-0.96) for polyp characterisation. Using optical diagnosis alone, 82 of 130 patients could be given a surveillance interval immediately after colonoscopy, and the same interval was found after formal histopathology in 80 patients (98%) using British guidelines and in 78 patients (95%) using US multisociety guidelines. INTERPRETATION For polyps less than 10 mm in size, in-vivo optical diagnosis seems to be an acceptable strategy to assess polyp histopathology and future surveillance intervals. Dispensing with formal histopathology for most small polyps found at colonoscopy could improve the efficiency of the procedure and lead to substantial savings in time and cost. FUNDING Leigh Family Trust, London, UK.

Development and validation of a novel method for assessing competency in polypectomy: direct observation of polypectomy skills

BACKGROUND Despite its ubiquitous use over the past 4 decades, there is no structured, formal method with which to assess polypectomy. OBJECTIVE To develop and validate a new method with which to assess competency in polypectomy. DESIGN Polypectomy underwent task deconstruction, and a structured checklist and global assessment scale were developed (direct observation of polypectomy skills [DOPyS]). Sixty bowel cancer screening polypectomy videos were randomly chosen for analysis and were scored independently by 7 expert assessors by using DOPyS. Each parameter and the global rating were scored from 1 to 4 (scores ≥3 = competency). The scores were analyzed by using generalizability theory (G theory). SETTING Multicenter. RESULTS Fifty-nine of the 60 videos were assessable and scored. The majority of the assessors agreed across the pass/fail divide for the global assessment scale in 58 of 59 (98%) polyps. For G-theory analysis, 47 of the 60 videos were analyzed. G-theory analysis suggested that DOPyS is a reliable assessment tool, provided that it is used by 2 assessors to score 5 polypectomy videos all performed by 1 endoscopist. DOPyS scores obtained in this format would reflect the endoscopists competence. LIMITATIONS Small sample and polyp size. CONCLUSIONS This study is the first attempt to develop and validate a tool designed specifically for the assessment of technical skills in performing polypectomy. G-theory analysis suggests that DOPyS could reliably reflect an endoscopists competence in performing polypectomy provided a requisite number of assessors and cases were used.

Factors associated with failed polyp retrieval at screening colonoscopy.

BACKGROUND Colonoscopy reduces colorectal cancer mortality and morbidity principally by the detection and removal of colon polyps. It is important to retrieve resected polyps to be able to ascertain their histologic characteristics. OBJECTIVE The aim of the study was to evaluate the cause of polyp retrieval failure. DESIGN Bowel cancer screening colonoscopy data were collected prospectively. SETTING The Bowel Cancer Screening Program in the National Health Service. PATIENTS Screening participants were referred to our screening center after a positive fecal occult blood test result. INTERVENTION A total of 4383 polyps were endoscopically removed from 1495 patients from October 2006 to February 2011. MAIN OUTCOME MEASUREMENTS The number, size, shape, and location of polyps; polyp removal method; quality of bowel preparation; total examination time; and insertion and withdrawal times in collected data were examined retrospectively. RESULTS The polyp retrieval rate was 93.9%, and the failure rate was 6.1%, thus 267 polyps were not retrieved. In univariate analysis, factors affecting polyp retrieval failure were small polyp size, sessile polyps, and cold snare polypectomy (P < .001). Polyp retrieval was less successful in the proximal colon (P = .002). In multivariate analysis, polyp size and method of removal were independent risk factors for polyp retrieval failure (P < .001). LIMITATIONS Retrospective study. CONCLUSION Small polyp size and cold snare removal were found to be significantly associated with polyp retrieval failure. It was difficult to retrieve small, sessile, and proximal colon polyps. Optical diagnosis could be an efficacious option as a surrogate for histologic diagnosis for these lesions in the near future.

Validation of a novel method for assessing competency in polypectomy

BACKGROUND There is a gap in the formal assessment of technical skills in polypectomy that is now considered an integral part of colonoscopy. Polypectomy has been shown to reduce the incidence of colorectal cancer but does have associated complications. Polypectomy competency assessment should arguably be a part of the certification process for all endoscopists. A polypectomy competency assessment tool (Direct Observation of Polypectomy Skills [DOPyS]) has been developed and its reliability examined. This study examined the ability of the DOPyS to reliably distinguish between endoscopists with different levels of experience, ie, its construct validity. OBJECTIVE To determine the construct validity of the DOPyS. DESIGN Videos of 32 polypectomies (endoscopic view only) were collected from 2 expert (> 1000 colonoscopies) endoscopists (17 polyps) and 6 intermediate-level (100-500 colonoscopies) endoscopists (15 polyps). The videos were edited to include only the entire polypectomy procedure, arranged in random order, and assessed blindly by 4 experienced endoscopists, only 2 of whom were familiar with polypectomy assessment by using the DOPyS before scoring. The differences in overall competency scores (range 1-4; competency, scores ≥ 3) for the expert and intermediate groups were compared by using the Fisher exact test. SETTING Single center. RESULTS The analysis suggested that both trained assessors familiar with the DOPyS could reliably distinguish between the expert and intermediate endoscopists (P = .049 and P < .001), with the expert group scoring higher than the intermediate one. For the assessors with no previous experience of the DOPyS, no such difference could be seen (P = .71 and P = .15). LIMITATIONS Small sample and polyp size. CONCLUSIONS The results of the analysis suggested that the DOPyS could reliably differentiate between polypectomies performed by endoscopists of different levels of experience, but only if the assessors were trained in the use of the assessment tool. Training is therefore required to use this tool reliably.

A novel method for determining the difficulty of colonoscopic polypectomy

Introduction Endoscopists are now expected to perform polypectomy routinely. Colonic polypectomy varies in difficulty, depending on polyp morphology, size, location and access. The measurement of the degree of difficulty of polypectomy, based on polyp characteristics, has not previously been described. Objective To define the level of difficulty of polypectomy. Methods Consensus by nine endoscopists regarding parameters that determine the complexity of a polyp was achieved through the Delphi method. The endoscopists then assigned a polyp complexity level to each possible combination of parameters. A scoring system to measure the difficulty level of a polyp was developed and validated by two different expert endoscopists. Results Through two Delphi rounds, four factors for determining the complexity of a polypectomy were identified: size (S), morphology (M), site (S) and access (A). A scoring system was established, based on size (1–9 points), morphology (1–3 points), site (1–2 points) and access (1–3 points). Four polyp levels (with increasing level of complexity) were identified based on the range of scores obtained: level I (4–5), level II (6–9), level III (10–12) and level IV (>12). There was a high degree of interrater reliability for the polyp scores (interclass correlation coefficient of 0.93) and levels (κ=0.888). Conclusions The scoring system is feasible and reliable. Defining polyp complexity levels may be useful for planning training, competency assessment and certification in colonoscopic polypectomy. This may allow for more efficient service delivery and referral pathways.

Is whole-colon investigation by colonoscopy, computerised tomography colonography or barium enema necessary for all patients with colorectal cancer symptoms, and for which patients would flexible sigmoidoscopy suffice? A retrospective cohort study

BACKGROUND For patients referred to hospital with suspected colorectal cancer (CRC), it is current standard clinical practice to conduct an examination of the whole colon and rectum. However, studies have shown that an examination of the distal colorectum using flexible sigmoidoscopy (FS) can be a safe and clinically effective investigation for some patients. These findings require validation in a multicentre study. OBJECTIVES To investigate the links between patient symptoms at presentation and CRC risk by subsite, and to provide evidence of whether or not FS is an effective alternative to whole-colon investigation (WCI) in patients whose symptoms do not suggest proximal or obstructive disease. DESIGN A multicentre retrospective study using data collected prospectively from two randomised controlled trials. Additional data were collected from trial diagnostic procedure reports and hospital records. CRC diagnoses within 3 years of referral were sourced from hospital records and national cancer registries via the Health and Social Care Information Centre. SETTING Participants were recruited to the two randomised controlled trials from 21 NHS hospitals in England between 2004 and 2007. PARTICIPANTS Men and women aged ≥ 55 years referred to secondary care for the investigation of symptoms suggestive of CRC. MAIN OUTCOME MEASURE Diagnostic yield of CRC at distal (to the splenic flexure) and proximal subsites by symptoms/clinical signs at presentation. RESULTS The data set for analysis comprised 7380 patients, of whom 59% were women (median age 69 years, interquartile range 62-76 years). Change in bowel habit (CIBH) was the most frequently presenting symptom (73%), followed by rectal bleeding (38%) and abdominal pain (29%); 26% of patients had anaemia. CRC was diagnosed in 551 patients (7.5%): 424 (77%) patients with distal CRC, 122 (22%) patients with cancer proximal to the descending colon and five patients with both proximal and distal CRC. Proximal cancer was diagnosed in 96 out of 2021 (4.8%) patients with anaemia and/or an abdominal mass. The yield of proximal cancer in patients without anaemia or an abdominal mass who presented with rectal bleeding with or without a CIBH or with a CIBH to looser and/or more frequent stools as a single symptom was low (0.5%). These low-risk groups for proximal cancer accounted for 41% (3032/7380) of the cohort; only three proximal cancers were diagnosed in 814 low-risk patients examined by FS (diagnostic yield 0.4%). LIMITATIONS A limitation to this study is that changes to practice since the trial ended, such as new referral guidelines and improvements in endoscopy quality, potentially weaken the generalisability of our findings. CONCLUSIONS Symptom profiles can be used to determine whether or not WCI is necessary. Most proximal cancers were diagnosed in patients who presented with anaemia and/or an abdominal mass. In patients without anaemia or an abdominal mass, proximal cancer diagnoses were rare in those with rectal bleeding with or without a CIBH or with a CIBH to looser and/or more frequent stools as a single symptom. FS alone should be a safe and clinically effective investigation in these patients. A cost-effectiveness analysis of symptom-based tailoring of diagnostic investigations for CRC is recommended. TRIAL REGISTRATION Current Controlled Trials ISRCTN95152621. FUNDING This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 66. See the NIHR Journals Library website for further project information.

PWE-010 Surveillance procedures in the St Mark's Bowel Cancer Screening Programme

Introduction The St Marks Bowel Cancer Screening Centre (BCSC) rolled out between 2006 and 2007. To date, 1200 colonoscopies have been performed by five accredited screening endoscopists. The programme is now into its third year and therefore second year of surveillance for high-risk patients. Methods To review the polyp surveillance procedures performed between Oct 2006 and July 2009. Data regarding the timing, number and size of polyps were collected prospectively. Result 1200 colonoscopies were performed between October 2006 and July 2009. 67 were 1-year polyp surveillance procedures (64 for high-risk polyps, two for intermediate risk, one for polyp cancer). There were 6.0 (3.76) polyps found per index procedure and 3.0 (2.4) per surveillance procedure (p<0.0001). In three cases, there were more polyps seen at surveillance than in the index procedure. Polyp size in the index procedure was 18.1 mm (11.8) compared to 5.26 mm (2.99) in the surveillance group (p<0.0001). Three of the 67 surveillance procedures revealed polyps >1 cm (11–16 mm). In two procedures there was an increase in the size of the largest polyp seen (9 mm to 14 mm and 6 mm to 9 mm). In 26 cases, the findings downgraded the risk from high to intermediate and in 30 cases, to low risk. In 11 cases, the risk remained high based on the number and size of polyps. Histologically all were tubular adenomas with low grade dysplasia. Conclusion In the majority of cases (62 (92%)) there was a reduction in both the size and number of polyps seen at 1-year surveillance. However, in a small number of cases there were significant polyp findings.

Construct Validity of a Tool for Assessing Competency in Polypectomy

Introduction There is a void in the formal assessment of technical skills in polypectomy which is now considered an integral part of colonoscopy. It has been shown to reduce the incidence of colorectal cancer but does have associated complications. Polypectomy competency assessment should arguably be a part of the certification process for all endoscopists. A polypectomy competency assessment tool (Direct Observation of Polypectomy Skills-DOPyS) has been developed and its construct validity, examined. Methods To determine construct validity of the DOPyS. Thirty-two polypectomy videos (incorporating the endoscopic view only) were collected from real patient procedures performed by two experienced (>1000 colonoscopies) endoscopists (17 videos) and six intermediate level (100–500 colonoscopies) endoscopists (15 videos). The videos were edited to include only the entire polypectomy procedure, arranged in random order, and assessed blindly by two experienced endoscopy assessors. Both assessors underwent a polypectomy assessment training session using the DOPyS prior to scoring. The DOPyS incorporates a 33-point procedure-specific checklist and an overall competency score. The differences in overall competency scores (range 1–4; scores ≥3=competency) for the expert and intermediate groups were compared, and considered significant (p value<0.05) using Fishers exact test. Results Conclusion The results of the analysis suggested that both blinded assessors were able to reliably differentiate between endoscopists of varying experience using the DOPyS (the expert group had higher scores than the intermediate group). Large-scale validation studies are required to further strengthen evidence for the use of this tool for routine polypectomy competency assessment. Table 1 PWE-009 Comparison of Overall Competency Scores for the Expert and Intermediate group of Endoscopists. Assessor Overall score Expert group number of videos (%) Intermediate group number of videos (%) p Value 1 Score <3 2 (12%) 7 (47%) 0.049 Score ≥3 15 (88%) 8 (53%) 2 Score <3 1 (6%) 12 (80%) <0.001 Score ≥3 16 (94%) 3 (20%) Competing interests None.

OC-054 Initial experience of St Mark's Bowel Cancer Screening Centre

Introduction St Marks Bowel Cancer Screening Centre (BCSC) was one ofthe first English screening centres rolled out between Oct 2006-Nov 2007. We report the preliminary experience of St Marks BCSC over the first 35 months of screening. Methods To review the outcomes of 1488 screening participants referred following positive FOBT. Those unfit for colonoscopy were offered alternatives such as CT Virtual Colonoscopy (VC). Data regarding gender, age, colonoscopy findings and screening outcomes were analysed. Results 98 815 FOBT kits were sent out and 42 523 returned (43% uptake).1488 positive FOBT participants were referred to the nurse clinic. 1339 (90%) attended. 57% were men. 1138 (85%) were suitable for colonoscopy, 122 (9%) for VC and 17 (1%) for flexible sigmoidoscopy. 62 (5%) were not referred further on medical grounds. 1057 (79%) screenees underwent first procedure colonoscopy, 115 had a VC and eight had a flexible sigmoidoscopy. 514 (44%) procedures were “normal”, 583 (50%) patients had polyps (155 (26%) high risk, 170 (29%) intermediate risk and 258 (45%) low risk polyps). In 583 patients with polyps, 1625 polyps were found (average 2.8 polyps per patient). 96% were adenomas. Median polyp size was 5 mm (1–80). 74 patients (6%) had colorectal cancer. Three patients had non-colonic incidental cancers. Overall, 1200 colonoscopies were performed by five screeners until September 2009 (1057 first procedure colonoscopies, 82 repeat colonoscopies, 61 surveillance procedures), with a 96% completion rate. There was one 30-day post surgical mortality. Conclusion Over the period reviewed, >1200 colonoscopies were performed with excellent (96%) completion rates. Significant pathology (cancers and polyps) was found in 45% of patients with a positive FOBT. Despite the polyp/adenoma detection rates being higher than those expected, cancer rates were lower than national figures. This was possibly due to a previous flexible sigmoidoscopy trial in the centre in 1999.

PWE-011 Consistency between bowel cancer screening colonoscopists of varying backgrounds: the St Mark's experience: Abstract PWE-011

Introduction St Marks Bowel Cancer Screening Centre (BCSC) became “live” from October 2006. It has five accredited screening colonoscopists of varying backgrounds-3 UK trained consultant gastroenterologists, one UK trained consultant nurse endoscopist and a very experienced Japanese trained honorary consultant endoscopist. Methods To compare endoscopic performance between the five screening colonoscopists at St Marks BCSC. Performance indicator data were prospectively collected for each endoscopist and analysed (October 2006–September 2009). Result Over 1200 colonoscopies were performed. Screeners 1, 2, 4 were accredited at the start. Screener 3 was accredited in 2007 and screener 5 has been performing screening lists for 13 months with no regular list to date (Abstract 011). Abstract PWE-011 Screener Numbers done Mean duration CR* (%) ADR† PR %‡ Cancer rate Adverse events National Target 150/year 35.0 90.0 11.0 1 287 25:42 94.01 63.87 90.54 4.74 1 2 280 24:10 95.27 67.91 88.51 5.22 5 3 229 38:06 97.38 72.97 94.6 2.25 4 4 298 22:32 93.2 38.57 94.4 4.1 2 5 106 25.19 98.11 70.48 88.5 3.81 1 p Value 0.15 <0.001 0.01 0.45 * Completion rate. † Adenoma detection rate. ‡ Polyp retrieval percentage. Conclusion Polyp/adenoma detection rates were higher than expected. There was a significantly lower ADR for Colonoscopist 4 (38.57), however this was above the national target. There were no other significant differences in performance. A longer procedure time may be associated with higher completion and adenoma detection rates. Cancer rates were lower than national figures possibly due to a previous flexible sigmoidoscopy trial in the centre in 1999.