Quality Indicators in Colonoscopy

Transcription

1 Symposium Symposium III - Lower GI : Quality Colonoscopy Quality Indicators in Colonoscopy Kyu Chan Huh Department of Internal medicine, Konyang University College of Medicine, Daejeon, Korea Introduction Colonoscopy is the most useful method to observe the colonic mucosa and is regarded the standard method for screening and surveillance of colorectal cancer. There are many evidences in reducing incidences of colorectal cancer (CRC) and cancer related mortality. In spite of the efficacy of colonoscopy in reducing the rate of CRC incidence and mortality, it has some major limitations. Firstly, the incidence of CRC is largely dependent upon the endoscopist s quality of the colonoscopic procedure and the ability to detect polyps. 1,2 Therefore, the quality of the procedure is emphasized. Secondly, the colonoscopy gives more protection against cancer developing in distal colon than in proximal colon cancer. 3,4 Thirdly there is considerable variation in the success rate among endoscopists in detection of CRC and adenoma. 5,6 Therefore we recognize the importance of quality benchmarks to overcome these limitations for screening colonoscopy. In 2002, quality indicators for colonoscopy were published by the American Society for Gastrointestinal Endoscopy/ American College of Gastroenterology (ASGE/ACG) and further adjusted by Rex et al. to improve the quality and efficacy of screening colonoscopy for constant quality improvement. 7,8 The recommended key indicators composed of three sections: pre-procedure, intra procedure, and post-procedure. The most important section was intra procedure, including (documentation of quality of bowel preparation, cecal intubation rates with photo-documentation of cecal landmarks, adenoma detection rate, withdrawal time >6 minutes, adequate resection of polyp). This section is important because it is critical to the detection of CRC and adenoma. We will review the diverse quality indicators and discuss what is the suitable colonoscopy indicator in reducing colorectal cancer development. Quality indicators 1. Bowel preparation For high quality colonoscopy, adequate bowel preparation is essential. In order to have ideal preparation, colon must be cleaned completely and without irritating side effects, so that there may be no fecal material remaining in the colon. In case of inadequate bowel preparation, there are several adverse effects, such as incomplete study, missed CRC and adenoma, and higher rates complication during the procedure. Good bowel preparation improves the rate of detection of neoplasia, reduces procedure time and complications. 10,11 Consequently, the quality of the bowel preparation is considered an important quality indicator. 12 In the ASGE recommended guidelines of bowel preparation; what is an adequate preparation, is that endoscopists are able to clearly detect lesions at a minimum of 5 mm. The percentage of examinations with adequate bowel preparation should be more than 90% of patients. 7 To achieve adequate preparation, we consider which cleansing regimen is most superior, and the method to cleanse the bowel. Regarding superiority of cleansing regimen, to date, there are no evidences that any colon-cleansing product supe- S44 62 nd Congress of the Korean Society of Gastrointestinal Endoscopy Clin Endosc Vol. 45 Suppl 1, 2012

2 Kyu Chan Huh riority to others. 13 Regardless the regimen of preparation, splitting the volume between the day before the test and the day of the examination makes the colon cleaner as opposed to whole dose volume. The splitting method helps to detect more polyps and improves tolerance. 14 The study by Gurudu et al. reported that split dose preparation gave significant improvement in colonoscopy completion rate, polyp detection rate (PDR), and adenoma detection rate (ADR) in colonoscopy. The implementation of split dose preparation thereby has the potential to improve both the quality and the effectiveness of colonoscopy. 15 The timing of the bowel preparation is also crucial. For high quality mucosal cleanliness, the examination should begin within hours after bowel preparation. That is to say, the ideal time between the last dose and the start of the examination should be greater than 2 hours and less than 6 hours. 14,16 If the preparation regimen starts near to the procedure, then mucosal cleanliness is low quality because there is no enough time to cleanse completely. Likewise if the preparation starts too early before procedure, then mucosal cleanliness is low quality because bile juice is expelled from small bowel. 2. Cecal intubation rate The definition of cecal intubation is the passage of the tip of colonoscope to a point proximal to the ileocecal valve and visualization of the entire cecum. A complete examination of mucosa of colon and rectum is essential to any colorectal cancer screening program, but the completion of a colonoscopy does not guarantee the quality of the examination of the mucosa, because observation of mucosa is performed mainly during the withdrawal phase and not during the insertion phase. Rapid and complete cecal intubation is not primary quality indicator but a proxy indicator of colonoscopy skill. According to the European Commission guideline, complete cecal intubation rate is at least 90% in screening colonocpy. 17 The US Multi-Society Task Force on Colorectal Cancer recommends that it should be 95% in screening colonoscopy and 90% in symptomatic patients. 7,18 Photographic record should be taken to confirm complete insertion and to avoid a medico-legal problem in every endoscopic procedure as a quality parameter. 19 It is particularly important to photograph, the appendiceal orifice, an image of the entire cecum, and the ileocecal valve. And, if possible, also the terminal ileum intubated should be photographed. If equipment is available, video recording gives clearer evidence of complete insertion. Studies have shown that the more experience performing colonoscopic procedures, the higher completion rates. By the study of Marshall et al, the completion rate within 30 min of first-year fellows, the second-year fellows and attending staff were 54%, 86% and 97% of cases respectively. 20 Conclusively there is a linear correlation between the number of colonoscopy cases and cecal intubation, and that this improvement continues even after finishing training. This raises the question of how many actual colonoscopy is required to consistently improve and maintain completion rate. The Mayo Clinic study showed that cecal intubation rates increased with increasing years of experience, Endoscopists who performed over 200 colonoscopies/year had higher completion rates compared with those doing less than 200 procedures/year. 21 As a result, the more endoscopists have experience of colonoscopy, the higher completion rate is gained. 3. Optimal withdrawal time Colonoscopy with drawal time is measured by the time that the colonoscope is extracted from cecum to anus, except during therapeutic procedures. The reason why withdrawal time is considered as one of quality indicators is based on that the longer withdrawal time, the more adenomas endocopist finds. In 2002 and 2006, the US Multisociety Task Force recommended that withdrawal time during colonoscopies, that did not include biopsies or polypectomies, should average at least 6-10 min. 7,8 The initial evidence on why the 6-min recommendation was based was scant. After Berclay RL et al. published a landmark prospective study paper concerning colonoscopic withdrawal time, with- Clin Endosc Vol. 45 Suppl 1, nd Congress of the Korean Society of Gastrointestinal Endoscopy S45

3 Quality Indicators in Colonoscopy drawal time is the most important quality indicator in colonoscopy. They reported that there was a strong correlation between withdrawal time in screening colonoscopies and adenoma detection rates. In addition, those colonoscopists, with average withdrawal times over 6 min detected adenomas 1 cm in 6.4% of screenings, compared with a 2.6% prevalence in colonoscopies performed by endoscopists with withdrawal times that averaged less than 6 min. 22 This dramatic difference in small and large adenoma detection with longer withdrawal time was followed up by the same group in a study demonstrating that the use of a timer in the room designed to force endoscopists to spend at least 8 min on examination time resulted in across-the-board improvements in adenoma detection. 23 The Mayo Clinic Rochester group also validated the 6-min withdrawal target as separating high from low adenoma detectors. 24 Their findings supported a colonoscopy withdrawal time of at least 7 min, which correlates with higher colon polyp detection rates. According to these studies, withdrawal time is the most important single aspect of withdrawal technique associated with adenoma detection rate. The speed of withdrawal time is the major factor of the quality of mucosal inspection. However there were three pitfalls in measuring these insistence. Firstly, in both studies of Barclay et al, the withdrawal time included intervention time such as polypectomy and biopsy. Secondly, the rapidity of withdrawal time is not only the primary factor of the quality of mucosal inspection during withdrawal. Thirdly, more recent other studies regarding withdrawal time, did not find any association between withdrawal time and detection of adenoma. 25,26 In the study of Moritz et al, they divided withdrawal time into Visual withdrawal time (VWT) and Overall withdrawal time (OWT). Visual withdrawal time (VWT) is defined as the time for a purely visual inspection that excludes both tissue sampling and therapeutic procedures. Overall withdrawal time (OWT) includes both tissue sampling and therapeutic procedures. In their result, the mean detection rate for polyps 5 mm was 20.8% in the group of endoscopists with a median VWT of 6 min, compared with 18.2% for the endoscopists with a median VWT of <6min (P =0.10). 27 In instance of OWT there was a significantly better PDR among those endoscopists with a median withdrawal time 6 min compared with <6 min (adjusted OR 2.07, CI , P<0.001). 27 This result was reasonable. Withdrawal time obviously becomes longer because procedures time such as polypectomy and biopsy was automatically added to withdrawal time and endoscopist paid more attention to detect adenoma, when polyp was found. Conclusively, the impact of withdrawal time on adenoma detection appears to be controversial. Although there is a powerful statistical association between withdrawal time and adenoma detection, withdrawal time was not a valid indicator of polyp detection. We do not have fully sufficient evidence that recommend withdrawal time as a quality indicator. The medico-legal implications of withdrawal time are important for endoscopist. Is the endoscpist who performs colonoscopy less than 6 min negligent? This is not acceptable because the colonic anatomy of patients was quite variable from one individual to another and withdrawal time includes not only observation time but also time for suctioning material and washing the colon walls depending on the quality of the preparation. Therefore, withdrawal time is better used as a parameter in the continuous quality improvement process, rather than used to evaluate an individual colonoscopy Adenoma detection rate (ADR) The fundamental purpose of screening colonoscopy is to detect and remove adenoma to prevent interval cancer because the removal of colonic adenomas reduces the risk of subsequent cancer. Quality indicator for screening colonoscopy was significantly associated with the risk of interval cancer. Unfortunately, adenomas are missed at colonoscopy more than expected and there is considerable variation between endoscopists in detecting adenoma. 1,29,30 The miss rate of a tandem study by Rex DK reported that the miss rate of advanced adenomas (>1 cm) was up to 6%, and in instance of adenomas less than 5 mm, miss rate is as high as 27%. 31 The best established neoplasia-related quality indicator reflected the actual prevalence of adenomas detected. So the Adenoma S46 62 nd Congress of the Korean Society of Gastrointestinal Endoscopy Clin Endosc Vol. 45 Suppl 1, 2012

4 Kyu Chan Huh detection rate (ADR) is a relatively good quality indicator in screening colonoscopy. The ADR is defined as the number of colonoscopies at which one or more histologically confirmed adenomas are found divided by the total number of colonoscopies performed. In 2002, the US Multisociety Task Force developed the adenoma detection rate (ADR) as a quality indicator. The ASGE/ACG recommended that adenomas should be detected in more than 25% of the asymptomatic male individuals more than 50 years old and in more than 15% of the asymptomatic female individuals more than 50 years old at first colonoscopy on the basis that prevalence rates of adenomas in screening colonoscopy have been consistently over 25% in men and 15% in women >50 years old. 8,32 In UK study, screening colonoscopy for the people with a positive guiac-based FOBT, has a 35% risk of detection of adenoma and a nearly 10.9% risk ofcancer. 33 Adenoma detection rate as quality indicator for screening colonoscopy was strongly correlated with the risk of interval cancer development. Recently Polish study group published landmark article concerning relationship between interval cancer and ADR as colonoscopic quality indicator. 5 In their study, the risk was significantly higher among subjects who underwent colonoscopies that were performed by endoscopists with an adenoma detection rate of less than 20%, than among subjects examined by endoscopists with a detection rate of 20% or more, and the cecal intubation rate was not associated with the risk of interval cancer. Consequently they describe that rigorous observation of the colorectal mucosa at screening colonosocopy is more important than any other factor as quality indicator. 34 According to the prevalence of adenomas in the United States, adenoma detection was recommended at 15% among women and 25% among men 50 years old. These recommendations did not have reliable evidences before this article was published. This study supported USA recommendation because 20 % ADR was very similar to these recommendations 5. Quality indicators other than ADR ADR is presently considered the best quality indicator for screening colonoscopy due to high correlation with the risk of interval cancer. But the ADR has problems. In measuring with ADR, it does not calculate at the time of the procedure because it requires substantial time to get pathology result. The other problem is that often it is troublesome because endoscopists intermittently review and analyze both endoscopy report and histology data. This is the reason why it s not used broadly in real clinical practice. Therefore many endoscopists seek other quality indicators, because ADR is not easy to operate and requires additional works. They are also seeking qualified colonoscopy quality indicator that gives similar information as ADR, and readily applied into clinical practice in order to enhance quality of endoscopic procedures. To calculate the Polypectomy rate (PR) is much easier than ADR because they are available at the time of colonoscopy, and faster to calculate, In recent studies by Williams JE et al, they showed that the PR was well correlated with ADR (r = 0.86, P<0.001). To attain the established benchmark ADRs for men (25%) and women (15%), endoscopists needed PDRs of 40% and 30%, respectively. Endoscopists with PRs in the highest quartile had a significantly higher ADR than did those in the lowest quartile in men (44.6% vs 19.4%, P <0001) and women (33.6% vs 11.6%, P <.0001). Endoscopists in the top polypectomy quartile also found more advanced adenomas than did endoscopists in the bottom quartile (men: 9.6% vs 4.6%, P=.0006; women: 6.3% vs 3.0%, P =.01). 35 They insisted that PR had a possibility of being a quality indicator and is a substituted for ADR. Other study by Goncalves et al reported that they used the polyp detection rate (PDR) as a surrogate marker of the ADR, and they were able to fulfill the requirements of this recently defined benchmark (44% for men and 25% for women in study of Williams JE et al). 36 France study group suggested mean number of polyp per colonoscopy (MNP) could be a surrogate bench mark for ADR. In their study, there was a significant correlation between counting polyps and ADR. Correlations were also significant between the ADR and PDR (Pearson coefficient r= 0.88, P <.0001) and between mean number of adenomas per Clin Endosc Vol. 45 Suppl 1, nd Congress of the Korean Society of Gastrointestinal Endoscopy S47

5 Quality Indicators in Colonoscopy colonoscopy (MNA) and MNP (Pearson coefficient r= 0.89, P<.0001 ). 37 The MNP (MNA) provided better discrimination than the PDR (ADR). On the basis of this result, the authors proposed that MNP might substitute for ADR because its calculation is not as time-consuming and it was available at the time of procedure. Conclusions The purpose of quality indicator for screening colonoscopy is to enhance and maintain effectiveness of colonoscopy for detection of neoplasia, and to evaluate endoscopists performance levels. There are many neoplasia-related quality indicators, such as bowel preparation, cecal intubation rate, ADR, withdrawal time, and so forth. Among them, to date ADR is the best quality indicator because ADR is very closely related with interval cancer. To achieve the highest level endoscopist, it is crucial that endoscopists are able to accurately visualize the whole mucosa of colon and rectum. Every endoscopist has an innate desire to daily improve his endoscopic quality. Quality can be further improved by benchmarking against other endoscopists and continuous study and practice. When we benchmark against other high quality endoscopist, we may improve to the same level as high quality endoscopists. References 1. Chen SC, Rex DK. Endoscopist can be more powerful than age and male gender in predicting adenoma detection at colonoscopy. Am JGastroenterol. 2007;102(4): Singh H, Nugent Z, Demers AA, Kliewer EV, Mahmud SM, Bernstein CN. The reduction in colorectal cancer mortality after colonoscopy varies by site of the cancer. Gastroenterology. 2010;139(4): Lakoff J, Paszat LF, Saskin R, Rabeneck L. Risk of developing proximal versus distal colorectal cancer after a negative colonoscopy: a population based study. Clin Gastroenterol Hepatol. 2008;6(10): Singh H, Nugent Z, Mahmud SM, Demers AA, Bernstein CN. Predictors of colorectal cancer after negative colonoscopy: a population-based study. Am J Gastroenterol. 2010;105(3): Kaminski MF, Regula J, Kraszewska E et al. Quality indicators for colonoscopy and the risk of interval cancer. N Engl J Med 2010;362: Lieberman D. A call to action - measuring the quality of colonoscopy. N Engl J Med 2006;355: Rex DK, Bond JH, Winawer S, et al. US Multi-Society Task Force on Colorectal Cancer. Quality in the technical performance of colonoscopy and the continuous quality improvement process for colonoscopy:recommendations of the US multi-society task force on colorectal cancer. Am J Gastroenterol. 2002;97(6): Rex DK, Petrini JL, Baron TH, et al. ASGE/ACG Taskforce on Quality in Endoscopy. Quality indicators for colonoscopy. Am J Gastroenterol. 2006;101(4): Gonçalves AR, Ferreira C, Marques A, Ribeiro LC, Velosa J. Assessment of quality in screening colonoscopy for colorectal cancer. Clin Exp Gastroenterol. 2011;4: Froehlich F, Wietlisbach V, Gonvers JJ et al. Impact of colonic cleansing on quality and diagnostic yield of colonoscopy: the European Panel of Appropriateness of Gastrointestinal Endoscopy European multicenter study. Gastrointest Endosc 2005;61(3): Rex DK, Imperiale TF, Latinovich DR, Bratcher LL. Impact of bowel preparation on efficiency and cost of colonoscopy. Am J Gastroenterol 2002;97(7): Thomas-Gibson S, Rogers P, Cooper S, et al. Judgement of the quality of bowel preparation at screening flexible sigmoidoscopy is associated with variability in adenoma detection rates. Endoscopy 2006;38: Belsey J, Epstein O, Heresbach D. Systematicreview: oral bowel preparation for colonoscopy. Aliment Pharmacol Ther 2007;25(4): Aoun E, Abdul-Baki H, Azar C et al. A randomized single-blind trial of split-dose PEG-electrolyte solution without dietary restriction compared with whole dose PEG-electrolyte solution with dietary restriction for colonoscopy preparation. Gastrointest Endosc 2005;62(2): Gurudu SR, Ramirez FC, Harrison ME, Leighton JA, Crowell MD. Increased adenoma detectionrate with system-wide S48 62 nd Congress of the Korean Society of Gastrointestinal Endoscopy Clin Endosc Vol. 45 Suppl 1, 2012

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