Accepted Manuscript Best of Series – Colonoscopy Amit Rastogi, MD, FASGE, Sachin Wani, MD PII:
S0016-5107(16)30582-X
DOI:
10.1016/j.gie.2016.09.013
Reference:
YMGE 10241
To appear in:
Gastrointestinal Endoscopy
Received Date: 8 September 2016 Accepted Date: 12 September 2016
Please cite this article as: Rastogi A, Wani S, Best of Series – Colonoscopy, Gastrointestinal Endoscopy (2016), doi: 10.1016/j.gie.2016.09.013. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
Best of Series – Colonoscopy Amit Rastogi, MD, FASGE1 and Sachin Wani, MD2 1. University of Kansas Medical Center, Kansas City, KS
RI PT
2) University of Colorado, Aurora, CO
Corresponding author: Amit Rastogi, MD, FASGE
SC
Associate Professor of Medicine
Kansas City, KS – 66160 Email - [email protected]
AC C
EP
[email protected]
TE D
Sachin Wani
M AN U
University of Kansas
ACCEPTED MANUSCRIPT
Best of Series
Amit Rastogi, MD, FASGE1 and Sachin Wani, MD2 1. University of Kansas Medical Center, Kansas City, KS
SC
2) University of Colorado, Aurora, CO
Corresponding author:
University of Kansas Kansas City, KS – 66160
EP
Introduction
TE D
Email - [email protected]
M AN U
Amit Rastogi, MD, FASGE Associate Professor of Medicine
RI PT
Colonoscopy
Colonoscopy is the most commonly performed endoscopic procedure in the United States and is
AC C
the preferred method to screen for colorectal cancer. Polypectomy during colonoscopy has been shown to decrease the incidence of colorectal cancer and associated mortality. However, colonoscopy is not a perfect tool and several aspects of this procedure continue to be the focus of active research to improve the quality as well as patient outcomes. In this review, we summarize the published literature in the year 2015 to 16 regarding the different facets of colonoscopy as it relates to colorectal cancer screening and prevention.
1
ACCEPTED MANUSCRIPT
RI PT
Bowel Preparation Adequate bowel preparation is a critical component of colonoscopy. The quality benchmark for bowel preparation is that it should be adequate enough to detect lesions > 5 mm in size. Several
SC
bowel preparation scales have been reported in the literature and a systematic review assessed the validity and reliability of these scales.1 The authors reported that the Boston Bowel
M AN U
Preparation Scale (BBPS) was the most thoroughly validated and should be used in the clinical setting. Increasing BBPS scores were associated with polyp detection, less repeat colonoscopies, shorter insertion/withdrawal times, with substantial to excellent inter- and intra-observer reliability. Calderwood et al2 evaluated the association between the quality of bowel preparation
TE D
by the BBPS and polyp detection rate and ADR in 2 large cohorts. The polyp detection rate associated with a total BBPS score of 6, 7, and 8 were higher than those associated with a BBPS of 9 in both cohorts. This trend was also observed for the detection rate of adenomas and
EP
advanced adenomas. Although the exact reasons for these findings are unclear, it is possible that excellent bowel preparation may lead to overconfidence on part of the endoscopist, resulting in
AC C
less-meticulous examination of the colon during withdrawal. Another possibility is that the cleaning process to achieve an excellent bowel preparation may distract the focus of the endoscopist from inspecting for polyps. Therefore based on the results of this study, it appears that striving to achieve the highest levels of bowel cleanliness may not improve clinically important end points like ADR or polyp detection rates. On the other hand, a recent study showed that there is a significantly higher miss rate of adenomas > 5 mm in colon segments with
2
ACCEPTED MANUSCRIPT
a BBPS score of 1 compared with a score of 2 (10.7%) or 3 (10.3%), whereas there was no difference in the miss rate between segments with a score of 2 versus 3.3
RI PT
Multiple studies have shown the superiority of split dose bowel prep compared with day-before regimens. This was further confirmed in a meta-analysis of 47 trials showing that split-dose bowel preparation resulted in significantly better colon cleansing than day-before preparation
SC
(OR = 2.51) across all types of colonic preparations.4 Further studies are needed to compare split dose regimens with same-day bowel preparation. Compliance to bowel preparation regimen is a
M AN U
pre-requisite for achieving good quality cleansing. A meta-analysis of 9 studies confirmed that consumption of a low residue diet in fact, showed favorable results compared with a clear liquid diet with regards to higher odds of tolerability (OR = 1.92) and willingness to repeat the preparation (OR = 1.86) without negatively affecting the quality of bowel preparation or increasing adverse effects.5 Therefore, low residue diet may be allowed on the day before
Sedation in colonoscopy
TE D
colonoscopy to improve compliance.
EP
A significant increase in the involvement of anesthesia services for colonoscopy over the past decade has been reported. Wernli and colleagues conducted a prospective cohort study that
AC C
quantified the difference in adverse events from colonoscopy among 3,168,228 unique colonoscopies performed with and without anesthesia services using an administrative claims database.6 Nationwide, a total of 34.4% of colonoscopies were conducted with anesthesia service with significant regional variation. Multivariable logistic regression models were adjusted for relevant variables to estimate the association between the use of anesthesia service and any adverse outcome and specific adverse events. The use of anesthesia services was associated with
3
ACCEPTED MANUSCRIPT
a 13% higher risk of any adverse event within 30 days. In addition, use of anesthesia services was also associated with a higher risk of perforation, hemorrhage, abdominal pain, adverse events related to anesthesia, and stroke. The risk of perforation associated with anesthesia
RI PT
services was increased only in patients undergoing polypectomy (OR 1.26). Interestingly,
regional differences in anesthesia related adverse outcomes were noted with the greatest increase in risk in regions with a low prevalence of use of anesthesia services. Plausible explanations for
SC
these adverse outcomes related to anesthesia services include direct effects related to anesthetic agents and increased colonic-wall tension related to absence of patient feedback. In contrast,
M AN U
results of a recent systematic review and meta-analysis compared sedation related cardiopulmonary adverse events associated with the use of propofol versus non-propofol agents for endoscopic procedures and showed that propofol sedation had similar risks of cardiopulmonary adverse events compared with non-propofol agents (hypoxia - pooled OR 0.82,
TE D
hypotension – OR 0.92).7 In fact, the use of propofol in non-advanced endoscopic procedures including colonoscopy was associated with a 39% reduction in adverse event rates (OR 0.61). Future research needs to clarify the role of anesthesia services using propofol during routine
EP
colonoscopy and its association with adverse events.
AC C
Recent changes to the standards for basic anesthesia monitoring require the use of capnography in all procedures using moderate sedation. The basic premise of use of capnography, that measures the CO2 concentration, is the real-time evaluation of alterations in ventilation status such as hypoventilation and hypercapnea that precede changes on pulse oximetry. A randomized blinded controlled trial by Mehta et al studied the impact of routine capnographic monitoring in detection of hypoxemia in healthy patients (ASA class I and II) undergoing colonoscopy and upper endoscopy under moderate sedation. There was no difference in the rates of hypoxemia 4
ACCEPTED MANUSCRIPT
(defined as SaO2 75,000 colonoscopies performed by 51 gastroenterologists.17 The mean withdrawal time was 8.3 minutes (range 3.9-14.4). Longer
EP
mean withdrawal times were associated with higher ADR – with a 3.6% increase in ADR/minute increase in withdrawal time. Furthermore, physicians’ mean annual withdrawal times were found
AC C
to be inversely associated with interval cancer incidence over a 410,687 person-years follow-up period. The adjusted incidence rate ratio (IRR) for withdrawal times 20% detection rate of adenoma and serrated polyps were associated with a
7
ACCEPTED MANUSCRIPT
reduced risk of interval cancer; odds ratio = 0.12 and 0.17, respectively.18 Withdrawal time of endoscopists was also associated with the detection of adenoma and serrated polyps.
RI PT
Although it is difficult to explain the exact mechanism of these findings, longer withdrawal time is probably a surrogate marker of a higher-quality mucosal inspection technique that results in higher ADR. It is recommended that withdrawal time should be measured and documented in all colonoscopy examinations, with the performance target being a ≥6 minutes average withdrawal
SC
time in negative-result screening colonoscopies.16 The importance of this was highlighted in
M AN U
another study. 19 When endoscopists were unaware that their withdrawal times were being monitored, the median was 4.5 minutes which increased to 7.3 minutes when they were made aware of being monitored. This increment in withdrawal time also resulted in a significant increase in the ADR from 21% to 36% (p < 0.001). This positive impact of monitoring also
TE D
known as the “Hawthorne effect” is a simple method of improving ADR. A major reason for missing polyps is the difficulty to completely examine the proximal aspects of the haustral folds. Cap assisted colonoscopy is a simple technique in which a transparent cap
EP
is attached to the tip of the colonoscope that helps to depress the haustral folds, thereby improving the visualization of their proximal aspects. Several studies have evaluated its impact
AC C
on ADR with conflicting results and the largest study from the US was published by Pohl et al.20 A total of 1113 patients were randomized to cap-assisted colonoscopy or standard colonoscopy by 10 endoscopists. There was no difference in the ADR (42% vs 40%; p=0.45) or the mean number of adenomas per patient (0.89 vs 0.82; p=0.43). ADR with cap was higher by up to 20% for some endoscopists and lower by up to 15% for others. Interestingly, the endoscopists who preferred cap-assisted colonoscopy achieved a higher ADR and advanced adenoma detection rates with cap compared with endoscopists who preferred standard colonoscopy. Based on this 8
ACCEPTED MANUSCRIPT
study, cap assisted colonoscopy may be a helpful technique to improve ADR for some endoscopists but its positive impact on ADR cannot be generalized.
RI PT
Other devices like the EndoRings and balloon colonoscope have also been evaluated for improving ADR. Both have shown lower adenoma miss rates compared with standard
colonoscopy in multicenter, randomized tandem studies.21, 22 Larger studies will be needed to
SC
confirm these findings and whether the extra expense involved with using these devices can be justified.
M AN U
Inadequate luminal distension during withdrawal may also lead to missing adenomas. Sequentially changing the position of patients from left lateral to supine and then to right lateral can help in improving the luminal distension of the ascending, transverse and left colon respectively. In a large, multicenter, randomized controlled study, this dynamic position change
TE D
during withdrawal was compared with complete examination in the left lateral position.23 A significantly higher ADR was seen in the position change group (42% vs 33%; p=0.002) as well as higher adenoma per patient (0.90 vs 0.67; p=0.01). This increase in number of adenomas
EP
detected was seen in the transverse and left colon and for endoscopists with a relatively low detection rate. Dynamic position change represents a simple and inexpensive means for
AC C
improving ADR especially if difficulty is encountered in adequate luminal distension.
Serrated Polyps
Up to a third of colon cancers can arise from the serrated neoplasia pathway. Therefore, detection and resection of premalignant serrated polyps is recognized as an important component of colorectal cancer screening and prevention. The clinical importance of serrated polyps as a 9
ACCEPTED MANUSCRIPT
marker of neoplasia was highlighted in a meta-analysis of 9 studies that showed the presence of proximal serrated polyps and large serrated polyps was associated with an increased risk of synchronous advanced neoplasia; odds ratio = 2.77 and 4.10 respectively.24 Therefore, the
RI PT
detection of these high risk serrated polyps should alert the endoscopist to be vigilant in
performing a meticulous inspection because of the high chances of detecting another advanced lesion. CT colonography has been recommended as one of the screening modalities for colorectal
SC
cancer. In a post hoc analysis of data from a randomized controlled trial comparing colonoscopy to CT colonography for population screening, the authors showed a significantly lower detection
M AN U
of patients with ≥1 high risk sessile serrated polyp (4.3% vs 0.8%; odds ratio = 5.5; P$7500/patient when an EMR strategy was employed.45 Finally, data from a
M AN U
population-based study that used the Surveillance, Epidemiology and End Results (SEER) database showed comparable mid- and long-term colorectal cancer-free survival rates between endoscopic and surgical management of stage 0 (Tis) malignant colon polyps.42 These compelling data regarding efficacy, safety, and cost-effectiveness make a strong argument for
TE D
endoscopic management of large colon polyps (adenomas and SSA/Ps) by trained and experienced endoscopists as the first line of therapy over surgical resection.
EP
Colonoscopy and inflammatory bowel disease (IBD) Current guidelines recommend enrolling patients in endoscopic surveillance programs and
AC C
obtaining random biopsies from all segments of the colon.46 A retrospective study showed that the incidence of CRC among patients with IBD without a recent colonoscopy was significantly higher than those with a recent colonoscopy (OR, 0.65; 95% CI, 0.45-0.93). In addition, colonoscopy within 36 months before the diagnosis of CRC was also associated with a reduced mortality rate (OR, 0.34; 95% CI, 0.12-0.95).47 These data add credence to the current recommendations of surveillance colonoscopies in patients with ulcerative colitis and Crohn’s colitis. 14
ACCEPTED MANUSCRIPT
The SCENIC international consensus document provided standardized terminology for reported findings and recommendations that addressed detection and management of dysplasia in patients with IBD undergoing surveillance colonoscopy.46 The key recommendations regarding detection
RI PT
included the use of high-definition colonoscopy rather than standard definition and the use of chromoendoscopy rather than high-definition white light colonoscopy. With regards to
management of dysplasia, surveillance colonoscopy was recommended over colectomy after
SC
complete removal of endoscopically resectable polypoid and non-polypoid dysplastic lesions. This document also provides guidance on training and implementation of high-quality
M AN U
endoscopic surveillance using high-definition white light endoscopy and chromoendoscopy. Recent studies have reported on the yield of dysplasia using white-light endoscopy, chromoendoscopy and NBI in IBD patients undergoing surveillance colonoscopy. A large Dutch study showed no difference in the dysplasia detection rate between 401 patients (440
TE D
colonoscopies) undergoing chromoendoscopy and 772 patients (1802 colonoscopies) undergoing white-light endoscopy (11% vs 10%, p=0.8).48 Gasia et al described a cohort of 454 patients undergoing surveillance using either random or target biopsies with different imaging
EP
modalities.49 A higher proportion of neoplastic lesions were detected in the targeted biopsy group
AC C
compared with procedures performed in the random biopsy group (19.1% vs 8.2%, p
S0016-5107(16)30582-X
DOI:
10.1016/j.gie.2016.09.013
Reference:
YMGE 10241
To appear in:
Gastrointestinal Endoscopy
Received Date: 8 September 2016 Accepted Date: 12 September 2016
Please cite this article as: Rastogi A, Wani S, Best of Series – Colonoscopy, Gastrointestinal Endoscopy (2016), doi: 10.1016/j.gie.2016.09.013. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
Best of Series – Colonoscopy Amit Rastogi, MD, FASGE1 and Sachin Wani, MD2 1. University of Kansas Medical Center, Kansas City, KS
RI PT
2) University of Colorado, Aurora, CO
Corresponding author: Amit Rastogi, MD, FASGE
SC
Associate Professor of Medicine
Kansas City, KS – 66160 Email - [email protected]
AC C
EP
[email protected]
TE D
Sachin Wani
M AN U
University of Kansas
ACCEPTED MANUSCRIPT
Best of Series
Amit Rastogi, MD, FASGE1 and Sachin Wani, MD2 1. University of Kansas Medical Center, Kansas City, KS
SC
2) University of Colorado, Aurora, CO
Corresponding author:
University of Kansas Kansas City, KS – 66160
EP
Introduction
TE D
Email - [email protected]
M AN U
Amit Rastogi, MD, FASGE Associate Professor of Medicine
RI PT
Colonoscopy
Colonoscopy is the most commonly performed endoscopic procedure in the United States and is
AC C
the preferred method to screen for colorectal cancer. Polypectomy during colonoscopy has been shown to decrease the incidence of colorectal cancer and associated mortality. However, colonoscopy is not a perfect tool and several aspects of this procedure continue to be the focus of active research to improve the quality as well as patient outcomes. In this review, we summarize the published literature in the year 2015 to 16 regarding the different facets of colonoscopy as it relates to colorectal cancer screening and prevention.
1
ACCEPTED MANUSCRIPT
RI PT
Bowel Preparation Adequate bowel preparation is a critical component of colonoscopy. The quality benchmark for bowel preparation is that it should be adequate enough to detect lesions > 5 mm in size. Several
SC
bowel preparation scales have been reported in the literature and a systematic review assessed the validity and reliability of these scales.1 The authors reported that the Boston Bowel
M AN U
Preparation Scale (BBPS) was the most thoroughly validated and should be used in the clinical setting. Increasing BBPS scores were associated with polyp detection, less repeat colonoscopies, shorter insertion/withdrawal times, with substantial to excellent inter- and intra-observer reliability. Calderwood et al2 evaluated the association between the quality of bowel preparation
TE D
by the BBPS and polyp detection rate and ADR in 2 large cohorts. The polyp detection rate associated with a total BBPS score of 6, 7, and 8 were higher than those associated with a BBPS of 9 in both cohorts. This trend was also observed for the detection rate of adenomas and
EP
advanced adenomas. Although the exact reasons for these findings are unclear, it is possible that excellent bowel preparation may lead to overconfidence on part of the endoscopist, resulting in
AC C
less-meticulous examination of the colon during withdrawal. Another possibility is that the cleaning process to achieve an excellent bowel preparation may distract the focus of the endoscopist from inspecting for polyps. Therefore based on the results of this study, it appears that striving to achieve the highest levels of bowel cleanliness may not improve clinically important end points like ADR or polyp detection rates. On the other hand, a recent study showed that there is a significantly higher miss rate of adenomas > 5 mm in colon segments with
2
ACCEPTED MANUSCRIPT
a BBPS score of 1 compared with a score of 2 (10.7%) or 3 (10.3%), whereas there was no difference in the miss rate between segments with a score of 2 versus 3.3
RI PT
Multiple studies have shown the superiority of split dose bowel prep compared with day-before regimens. This was further confirmed in a meta-analysis of 47 trials showing that split-dose bowel preparation resulted in significantly better colon cleansing than day-before preparation
SC
(OR = 2.51) across all types of colonic preparations.4 Further studies are needed to compare split dose regimens with same-day bowel preparation. Compliance to bowel preparation regimen is a
M AN U
pre-requisite for achieving good quality cleansing. A meta-analysis of 9 studies confirmed that consumption of a low residue diet in fact, showed favorable results compared with a clear liquid diet with regards to higher odds of tolerability (OR = 1.92) and willingness to repeat the preparation (OR = 1.86) without negatively affecting the quality of bowel preparation or increasing adverse effects.5 Therefore, low residue diet may be allowed on the day before
Sedation in colonoscopy
TE D
colonoscopy to improve compliance.
EP
A significant increase in the involvement of anesthesia services for colonoscopy over the past decade has been reported. Wernli and colleagues conducted a prospective cohort study that
AC C
quantified the difference in adverse events from colonoscopy among 3,168,228 unique colonoscopies performed with and without anesthesia services using an administrative claims database.6 Nationwide, a total of 34.4% of colonoscopies were conducted with anesthesia service with significant regional variation. Multivariable logistic regression models were adjusted for relevant variables to estimate the association between the use of anesthesia service and any adverse outcome and specific adverse events. The use of anesthesia services was associated with
3
ACCEPTED MANUSCRIPT
a 13% higher risk of any adverse event within 30 days. In addition, use of anesthesia services was also associated with a higher risk of perforation, hemorrhage, abdominal pain, adverse events related to anesthesia, and stroke. The risk of perforation associated with anesthesia
RI PT
services was increased only in patients undergoing polypectomy (OR 1.26). Interestingly,
regional differences in anesthesia related adverse outcomes were noted with the greatest increase in risk in regions with a low prevalence of use of anesthesia services. Plausible explanations for
SC
these adverse outcomes related to anesthesia services include direct effects related to anesthetic agents and increased colonic-wall tension related to absence of patient feedback. In contrast,
M AN U
results of a recent systematic review and meta-analysis compared sedation related cardiopulmonary adverse events associated with the use of propofol versus non-propofol agents for endoscopic procedures and showed that propofol sedation had similar risks of cardiopulmonary adverse events compared with non-propofol agents (hypoxia - pooled OR 0.82,
TE D
hypotension – OR 0.92).7 In fact, the use of propofol in non-advanced endoscopic procedures including colonoscopy was associated with a 39% reduction in adverse event rates (OR 0.61). Future research needs to clarify the role of anesthesia services using propofol during routine
EP
colonoscopy and its association with adverse events.
AC C
Recent changes to the standards for basic anesthesia monitoring require the use of capnography in all procedures using moderate sedation. The basic premise of use of capnography, that measures the CO2 concentration, is the real-time evaluation of alterations in ventilation status such as hypoventilation and hypercapnea that precede changes on pulse oximetry. A randomized blinded controlled trial by Mehta et al studied the impact of routine capnographic monitoring in detection of hypoxemia in healthy patients (ASA class I and II) undergoing colonoscopy and upper endoscopy under moderate sedation. There was no difference in the rates of hypoxemia 4
ACCEPTED MANUSCRIPT
(defined as SaO2 75,000 colonoscopies performed by 51 gastroenterologists.17 The mean withdrawal time was 8.3 minutes (range 3.9-14.4). Longer
EP
mean withdrawal times were associated with higher ADR – with a 3.6% increase in ADR/minute increase in withdrawal time. Furthermore, physicians’ mean annual withdrawal times were found
AC C
to be inversely associated with interval cancer incidence over a 410,687 person-years follow-up period. The adjusted incidence rate ratio (IRR) for withdrawal times 20% detection rate of adenoma and serrated polyps were associated with a
7
ACCEPTED MANUSCRIPT
reduced risk of interval cancer; odds ratio = 0.12 and 0.17, respectively.18 Withdrawal time of endoscopists was also associated with the detection of adenoma and serrated polyps.
RI PT
Although it is difficult to explain the exact mechanism of these findings, longer withdrawal time is probably a surrogate marker of a higher-quality mucosal inspection technique that results in higher ADR. It is recommended that withdrawal time should be measured and documented in all colonoscopy examinations, with the performance target being a ≥6 minutes average withdrawal
SC
time in negative-result screening colonoscopies.16 The importance of this was highlighted in
M AN U
another study. 19 When endoscopists were unaware that their withdrawal times were being monitored, the median was 4.5 minutes which increased to 7.3 minutes when they were made aware of being monitored. This increment in withdrawal time also resulted in a significant increase in the ADR from 21% to 36% (p < 0.001). This positive impact of monitoring also
TE D
known as the “Hawthorne effect” is a simple method of improving ADR. A major reason for missing polyps is the difficulty to completely examine the proximal aspects of the haustral folds. Cap assisted colonoscopy is a simple technique in which a transparent cap
EP
is attached to the tip of the colonoscope that helps to depress the haustral folds, thereby improving the visualization of their proximal aspects. Several studies have evaluated its impact
AC C
on ADR with conflicting results and the largest study from the US was published by Pohl et al.20 A total of 1113 patients were randomized to cap-assisted colonoscopy or standard colonoscopy by 10 endoscopists. There was no difference in the ADR (42% vs 40%; p=0.45) or the mean number of adenomas per patient (0.89 vs 0.82; p=0.43). ADR with cap was higher by up to 20% for some endoscopists and lower by up to 15% for others. Interestingly, the endoscopists who preferred cap-assisted colonoscopy achieved a higher ADR and advanced adenoma detection rates with cap compared with endoscopists who preferred standard colonoscopy. Based on this 8
ACCEPTED MANUSCRIPT
study, cap assisted colonoscopy may be a helpful technique to improve ADR for some endoscopists but its positive impact on ADR cannot be generalized.
RI PT
Other devices like the EndoRings and balloon colonoscope have also been evaluated for improving ADR. Both have shown lower adenoma miss rates compared with standard
colonoscopy in multicenter, randomized tandem studies.21, 22 Larger studies will be needed to
SC
confirm these findings and whether the extra expense involved with using these devices can be justified.
M AN U
Inadequate luminal distension during withdrawal may also lead to missing adenomas. Sequentially changing the position of patients from left lateral to supine and then to right lateral can help in improving the luminal distension of the ascending, transverse and left colon respectively. In a large, multicenter, randomized controlled study, this dynamic position change
TE D
during withdrawal was compared with complete examination in the left lateral position.23 A significantly higher ADR was seen in the position change group (42% vs 33%; p=0.002) as well as higher adenoma per patient (0.90 vs 0.67; p=0.01). This increase in number of adenomas
EP
detected was seen in the transverse and left colon and for endoscopists with a relatively low detection rate. Dynamic position change represents a simple and inexpensive means for
AC C
improving ADR especially if difficulty is encountered in adequate luminal distension.
Serrated Polyps
Up to a third of colon cancers can arise from the serrated neoplasia pathway. Therefore, detection and resection of premalignant serrated polyps is recognized as an important component of colorectal cancer screening and prevention. The clinical importance of serrated polyps as a 9
ACCEPTED MANUSCRIPT
marker of neoplasia was highlighted in a meta-analysis of 9 studies that showed the presence of proximal serrated polyps and large serrated polyps was associated with an increased risk of synchronous advanced neoplasia; odds ratio = 2.77 and 4.10 respectively.24 Therefore, the
RI PT
detection of these high risk serrated polyps should alert the endoscopist to be vigilant in
performing a meticulous inspection because of the high chances of detecting another advanced lesion. CT colonography has been recommended as one of the screening modalities for colorectal
SC
cancer. In a post hoc analysis of data from a randomized controlled trial comparing colonoscopy to CT colonography for population screening, the authors showed a significantly lower detection
M AN U
of patients with ≥1 high risk sessile serrated polyp (4.3% vs 0.8%; odds ratio = 5.5; P$7500/patient when an EMR strategy was employed.45 Finally, data from a
M AN U
population-based study that used the Surveillance, Epidemiology and End Results (SEER) database showed comparable mid- and long-term colorectal cancer-free survival rates between endoscopic and surgical management of stage 0 (Tis) malignant colon polyps.42 These compelling data regarding efficacy, safety, and cost-effectiveness make a strong argument for
TE D
endoscopic management of large colon polyps (adenomas and SSA/Ps) by trained and experienced endoscopists as the first line of therapy over surgical resection.
EP
Colonoscopy and inflammatory bowel disease (IBD) Current guidelines recommend enrolling patients in endoscopic surveillance programs and
AC C
obtaining random biopsies from all segments of the colon.46 A retrospective study showed that the incidence of CRC among patients with IBD without a recent colonoscopy was significantly higher than those with a recent colonoscopy (OR, 0.65; 95% CI, 0.45-0.93). In addition, colonoscopy within 36 months before the diagnosis of CRC was also associated with a reduced mortality rate (OR, 0.34; 95% CI, 0.12-0.95).47 These data add credence to the current recommendations of surveillance colonoscopies in patients with ulcerative colitis and Crohn’s colitis. 14
ACCEPTED MANUSCRIPT
The SCENIC international consensus document provided standardized terminology for reported findings and recommendations that addressed detection and management of dysplasia in patients with IBD undergoing surveillance colonoscopy.46 The key recommendations regarding detection
RI PT
included the use of high-definition colonoscopy rather than standard definition and the use of chromoendoscopy rather than high-definition white light colonoscopy. With regards to
management of dysplasia, surveillance colonoscopy was recommended over colectomy after
SC
complete removal of endoscopically resectable polypoid and non-polypoid dysplastic lesions. This document also provides guidance on training and implementation of high-quality
M AN U
endoscopic surveillance using high-definition white light endoscopy and chromoendoscopy. Recent studies have reported on the yield of dysplasia using white-light endoscopy, chromoendoscopy and NBI in IBD patients undergoing surveillance colonoscopy. A large Dutch study showed no difference in the dysplasia detection rate between 401 patients (440
TE D
colonoscopies) undergoing chromoendoscopy and 772 patients (1802 colonoscopies) undergoing white-light endoscopy (11% vs 10%, p=0.8).48 Gasia et al described a cohort of 454 patients undergoing surveillance using either random or target biopsies with different imaging
EP
modalities.49 A higher proportion of neoplastic lesions were detected in the targeted biopsy group
AC C
compared with procedures performed in the random biopsy group (19.1% vs 8.2%, p
