Neoplasms

All Conditions

Adenoma

Neoplasms, Glandular and Epithelial

Neoplasms by Histologic Type

Herbal and Botanical

All Drugs and Chemicals

Cola

For patients in the CE group, the colonoscope was withdrawn directly from the splenic flexure to the rectum, and polyps that were found were removed

For patients in the SE group, the colonoscope was reinserted into the cecum, additional polyps were removed from the proximal colon during the third withdrawall(third pass), and the remainder of the colon from splenic flexure to rectum was examined in a standard manner

second examination of the proximal colon

xiaojia zhu

fangxi cheng

Xiaojia Zhu

li yang

.Studies have demonstrated that the second examination of the proximal colon can significantly increase the proximal ADR.This study aimed to determine the impact of second examination of the proximal colon on AMR compared to conventional examination.Consecutive patients aged 40-75years undergoing colonoscopy for screening.Tandem withdrawal was used in the proximal colon.Patients were randomly assigned to either the second examination(SE) or the conventional examination(CE) group.The primary outcome measure was proximal AMR,defined as the number of proximal adenomas detected in the second pass（CE group）or the third pass（SE group）divided by the total number of proximal adenomas detected during the tandem colonoscopy.

Colonoscopy is routinely performed for detection and removal of colorectal adenomas, thereby preventing colorectal cancer(CRC).The adenoma miss rates(AMR) still ranges between 26%-62%,and missed adenomas may contribute to the development of interval CRC.Therefore, there is currently considerable interest in improving AMR during a colonoscopy.The second examination has recently attracted increasing attention.since it only requires a relatively short procedure time and does not require any specialized equipment.Thus, we performed an randomized controlled trial (RCT) in patients undergoing colonoscopy for screening to determine the impact of second examination of the proximal colon on AMR compared to conventional examination.

This study aimed to determine the impact of second examination of the proximal colon on AMR compared to conventional examination.Consecutive patients aged 40-75years undergoing colonoscopy for screening.Patients were excluded if they failed cecal intubation, prior colorectal resection, inadequate bowel preparation quality (Boston Bowel Preparation Scale (BBPS)scores \< 2 in any segment of the colon), inflammatory bowel disease or intestinal tuberculosis, familial polyposis syndrome, coagulation dysfunction, or polyp retrieval failure.

Consecutive patients aged 40-75years undergoing colonoscopy for screening.Tandem withdrawal was used in the proximal colon.The colonoscope was inserted in a standard manner. After successful insertion in the cecum, the colonoscope was slowly withdrawn to the splenic flexure and the mucosa was carefully observed, the polyps that were found were removed for histopathologic examination(first pass).Once the splenic flexure was reached, the position of splenic flexure was marked by creating a suction mark or taking a small biopsy. Subsequently, the colonoscope was advanced to the cecum again, additional polyps were removed from the proximal colon during the second withdrawal(second pass). When the colonoscope completed the two forward view examination of the proximal colon (defined as proximal to the splenic flexure), patients were randomly assigned to either the second examination(SE) or the conventional examination(CE) group. The randomization sequence was computer-generated and concealed in sequentially numbered sealed opaque envelopes, at this moment, the envelope was opened. For patients in the SE group, the colonoscope was reinserted into the cecum, additional polyps were removed from the proximal colon during the third withdrawall(third pass), and the remainder of the colon from splenic flexure to rectum was examined in a standard manner. For patients in the CE group, the colonoscope was withdrawn directly from the splenic flexure to the rectum, and polyps that were found were removed. Multiple diminutive hyperplastic polyps (≤ 5 mm) in the sigmoid colon and rectum were not subjected to removal, and only one representative polyp biopsy was analyzed. We recorded all adverse events at the time of the colonoscopy and for one week there after The cecal intubation time and withdrawal time were recorded by an assistant with a stopwatch. The time for polypectomy and biopsy were excluded from the withdrawal time. The primary outcome measure was proximal AMR,defined as the number of proximal adenomas detected in the second pass（CE group）or the third pass（SE group）divided by the total number of proximal adenomas detected during the tandem colonoscopy.

Impact of SE of the Proximal Colon on the AMR

Impact of the Second vs. Conventional Examination of the Proximal Colon on Adenoma Miss Rate, a Prospective Randomized Tandem Trial

the number of proximal adenomas detected in the second pass（CE group）or the third pass（SE group）divided by the total number of proximal adenomas detected during the tandem colonoscopy.

the number of proximal polyps detected in the second pass（CE group）or the third pass（SE group）divided by the total number of proximal polyps detected during the tandem colonoscopy

the number of patients in whom proximal adenomas or polyps were detected only in the second pass（CE group）or the third pass（SE group）divided by the total number of patients with at least one proximal adenoma or polyp detected during the tandem colonoscopy

the proportion of patients with at least one adenoma or polyp detected during the tandem colonoscopy

the total number of adenomas or polyps divided by the total number of patients

Advanced adenoma is defined as an adenoma with a size ≥10 mm, with tubulovillous or villous histology, or with high-grade dysplasia.

Third People's Hospital of Jingdezhen City

Symptoms and General Pathology

Polyps

Water exchange (WE) method was used for insertion to the cecum.

Air insufflation (AI) method was used for insertion to the cecum.

Water exchange (WE) method was used for insertion to the cecum. And air was insufflated to distend the lumen for inspection and biopsy or polypectomy during withdrawal procedure.

Water exchange (WE) method

Air insufflation (AI) method was used for insertion to the cecum. And air was insufflated to distend the lumen for inspection and biopsy or polypectomy during withdrawal procedure.

Air insufflation (AI) method.

Gui Ren, MD

Yanglin Pan, MD

Patients with colorectal adenomas are suggested to receive polypectomy. A substantial number of adenomas may be missed in patients with polyps found by previous colonoscopy. And water exchange (WE) method may increase the detection of missed adenoma compared with traditional air insufflation (AI) colonoscopy. The investigators aim to investigate whether water exchange colonoscopy method, compared with air insufflation method, can improve the detection of missed adenomas in patients undergoing selective polypectomy.

For WE method, the air pump was turned off for the full duration of insertion to avoid inadvertent air insufflations and colon elongation. Residual air in the lumen was suctioned to minimize angulations at flexures. Water at 37°C was infused with a pump (Olympus) through the biopsy channel to confirm correct tip orientation for scope advancement. The infused water was removed predominantly by suction when the colonoscope was smoothly advanced during the insertion phase, and turbid luminal water due to residual feces was exchanged by clean water until the lumen was clearly visualized. Occasionally, if it was difficult to determine whether the colonoscope tip was in the cecum, air was allowed to be insufflated for observation. If the position of the scope tip was confirmed to be not in the cecum, insufflated air would be removed by suction and the WE method would be continuously used until successful intubation.

For the AI method, water was not used, and air was insufflated during insertion.

Air was insufflated to distend the lumen for inspection and biopsy or polypectomy during withdrawal for both methods. Polyps will be removed by forceps biopsy (polyps size \<3mm), cold snare technique (3-6mm) or endoscopic mucosal resection (size≥6mm).

Effect of Water Exchange Method on Adenoma Miss Rates in Patients Undergoing Selective Polypectomy

Effect of Water Exchange Method on Adenoma Miss Rates in Patients Undergoing Selective Polypectomy: a Single-centered, Randomized Controlled Study

Adenoma miss rate was calculated as the number of patients with one and more additional adenomas during polypectomy procedure divided by the total number of patients in each group.

Adenoma-level miss rate was calculated as the number of additional adenomas detected in polypectomy procedure divided by the total number of adenomas in each group.

Advanced adenoma: any with 3 or more adenomas of any size, 1 or more large adenomas 1 cm, or 1 or more adenomas with villous architecture or highgrade dysplasia.

The mean number of adenoma per positive patient

The Boston Bowel Preparation Scale (BBPS): cleanliness of each part of the colon: 0=unprepared colon segment with mucosa not seen because of solid stool that cannot be cleared; 1=portion of mucosa of the colon segment seen, but other areas of the colon segment not well seen because of staining, residual stool, and/or opaque liquid; 2=minor amount of residual staining, small fragments of stool and/or opaque liquid, but mucosa of colon segment seen well; 3=entire mucosa of colon segment seen well with no residual staining, small fragments of stool, or opaque liquid.

Air Force Military Medical University, China

Associated professor

During the insertion phase of the first-pass colonoscopy, water exchange (WE) method was used. WE entailed the infusion of water to open the lumen and sequentially suction of water. When the cecum was reached and after most of the water was suctioned to collapse the cecal lumen, CO2 was opened during the withdrawal phase of the first-pass colonoscopy. After the first complete withdrawal of the colonoscope, a second colonoscopic examination aided by CO2 insufflation during insertion and withdrawal was performed by the same endoscopist. The colonoscope was reinserted into the cecum as quickly as possible, and the entire colon was re-examined. Polyp resection was carried out during insertion and withdrawal of the first- and second-pass examinations.

During the first-pass colonoscopy, the procedure was performed in the usual fashion, with minimal CO2 insufflation to aid insertion. Cleaning of colon was predominantly performed during withdrawal. After the first complete withdrawal of the colonoscope, a second colonoscopic examination aided by CO2 insufflation during insertion and withdrawal was performed by the same endoscopist. The colonoscope was reinserted into the cecum as quickly as possible, and the entire colon was re-examined. Polyp resection was carried out during insertion and withdrawal of the first- and second-pass examinations.

During back-to-back colonoscopy, the first examination was completed with water exchange during insertion and CO2 insufflation during withdrawal. The second examination was completed with CO2 insufflation during both the insertion and withdrawal.

Water exchange colonoscopy

During back-to-back colonoscopy, the first examination was completed with CO2 insufflation during both the insertion and withdrawal. The second examination was also completed with CO2 insufflation during both the insertion and withdrawal.

CO2 insufflation colonoscopy

Chi-Liang Cheng

This was an observational study comparing consecutive group of WE and CO2 insufflation in terms of right and proximal colon AMR by tandem colonoscopy.

This was a prospective observational study to assess how WE colonoscopy would fit into clinical and research practices. We first observed whether optimal WE colonoscopy decreased the AMR in the right and proximal colon in a tandem approach. If WE did lower the AMR as compared with data in the literature, a randomized RCT deserves to be studied. For the calculation of sample size in the upcoming RCT, the AMR in the CO2 group would be collected. The differences of the AMRs in the right and proximal colon determined by tandem colonoscopy using WE or CO2 insufflation would then be compared.

Adenoma Miss Rate With Water Exchange vs Carbon Dioxide Colonoscopy

Water Exchange Colonoscopy Decreased Adenoma Miss Rates in the Right and Proximal Colon: An Observational Study Using A Tandem Colonoscopy Approach

Right-colon (cecum, A-colon, hepatic flexure) adenomas detected on the second-pass examination were used for the calculation of adenoma miss. Adenoma miss rate was calculated as the number of adenomas missed in the first colonoscopy divided by the total number of adenomas detected during both the first and second colonoscopies.

Proximal-colon (cecum, A-colon, hepatic flexure, T-colon) adenomas detected on the second-pass examination were used for the calculation of adenoma miss. Adenoma miss rate was calculated as the number of adenomas missed in the first colonoscopy divided by the total number of adenomas detected during both the first and second colonoscopies.

Evergreen General Hospital, Taiwan

M.D.

Water Exchange Colonoscopy

CO2 Insufflation Colonoscopy

During the insertion phase of the first-pass colonoscopy, WE method was used. When the cecum was reached, CO2 was opened during the withdrawal phase of the first-pass colonoscopy. After the first complete withdrawal of the colonoscope, a second colonoscopic examination aided by CO2 insufflation during insertion and withdrawal was performed by the same endoscopist. The colonoscope was reinserted into the cecum as quickly as possible, and the entire colon was re-examined. Polyp resection was carried out during insertion and withdrawal of the first- and second-pass examinations.

Total

Age, Continuous

Sex: Female, Male

Race and Ethnicity were not collected from any participant.

Race and Ethnicity Not Collected

Taiwan

Region of Enrollment

Dr. Chi-Liang Cheng

Percentage of Overall Detected Adenomas Missed During the First Right-Colon Colonoscopy

Percentage of Overall Detected Adenomas Missed During the First Proximal-Colon Colonoscopy

Overall Study

Colonic Polyps

Patients in 6-minute then 9-minute withdrawal group will first be carefully observed in 6 minutes then in 9 minutes during the segmental withdrawal.

At 6-minute withdrawal, the left colon, transverse colon and right colon will take 2 minutes each. Then at 9-minute withdrawal, the observation of the left colon, transverse colon and the right colon will be maintained for 3 minutes each.

A stop watch will be utilized to remind endoscopists the withdrawal time. The time to perform polyp biopsy will not be included.

Patients in 9-minute then 6-minute withdrawal group will first be carefully observed in 9 minutes then in 6 minutes during the segmental withdrawal.

At 9-minute withdrawal, the left colon, transverse colon and right colon will take 3 minutes each. Then at 6-minute withdrawal, the observation of the left colon, transverse colon and the right colon will be maintained for 2 minutes each.

A stop watch will be utilized to remind endoscopists the withdrawal time. The time to perform polyp biopsy will not be included.

Patients in 6-minute then 9-minute withdrawal group will first be carefully observed in 2 minutes then in 3 minutes during each colonic segment.

In actual performance, withdrawal of the right colon, transverse colon and the left colon can be operated in segmental tandem colonoscopy. Taking the right colon as an example, after the endoscope reaches the cecum, it can be withdrawn to the splenic curvature in 2 minutes, then reentered the cecum and withdrawn to the splenic curvature in 3 minutes.

6-minute then 9-minute withdrawal

Patients in 9-minute then 6-minute withdrawal group will first be carefully observed in 3 minutes then in 2 minutes during each colonic segment.

In actual performance, withdrawal of the right colon, transverse colon and the left colon can be operated in segmental tandem colonoscopy. Taking the right colon as an example, after the endoscope reaches the cecum, it can be withdrawn to the splenic curvature in 3 minutes, then reentered the cecum and withdrawn to the splenic curvature in 2 minutes.

9-minute then 6-minute withdrawal

Zhaoshen Li, M.D

A mean withdrawal time of at least 6 minutes has been considered to be one of the critical quality criterions of colonoscopy. Recently, our group completed a multicenter randomized controlled trial, which proved that prolonging the withdrawal time to 9 minutes could significantly improve the adenoma detection rate of colonoscopists, especially for young colonoscopists and proximal colon. However, it has some limitations in included participates (mixed indications for colonoscopy) and cannot illustrate the impact of withdrawal time on adenoma miss rate in a parallel randomized design. It is necessary to include tandem colonoscopy and adopt strict criteria of the screening population to confirm the effect of the 9-minute withdrawal time on the adenoma miss rate. Therefore, the investigators plan to conduct a multicenter, randomized controlled trial of tandem colonoscopy to compare adenoma miss rate of 6-minute and 9-minute withdrawal in screening population.

9 Minutes for Tandem Colonoscopy Withdrawal

Impact of 9-minute Withdrawal Time on Adenoma Miss Rate: A Multicenter, Prospective, Randomized Controlled Trial of Tandem Colonoscopy

Adenomas detected in the second-pass examination were defined as missed adenomas; the AMR was defined as follows: number of adenomas detected in the second-pass examination/total number of adenomas detected in the two pass.

AAMR is the number of advanced adenomas detected in the second-pass examination/total number of advanced adenomas detected in the two pass.

ADR is the number of patients with at least one adenoma, divided by the total number of patients.

APC was calculated as the number of adenomas detected during colonoscopy withdraw divided by the number of colonoscopies.

the number of participants with adenomas detected only during the second-pass colonoscopy divided by the total number of participants with adenomas detected during the tandem colonoscopy

No.85 Hospital, Changning, Shanghai, China

Yantaishan Hospital of Yantai City, Yantai, China

Seventh Medical Center of PLA Army General Hospital

The First Affiliated Hospital of Dalian Medical University

The First Affiliated Hospital of the Medical College, Shihezi University

Shanghai 8th People's Hospital

Shanxi Provincial People's Hospital

Qinghai People's Hospital

Leqing People's Hospital

Afﬁliated Hospital of North Sichuan Medical College

Zhejiang University

Songjiang Hospital Affiliated to Shanghai Jiaotong University School of Medicine

The General Hospital of Eastern Theater Command

Heilongjiang provincial hospital

The Second Hospital of Hebei Medical University

Changhai Hospital

Director of Gastroenterology Dept

Digestive System Diseases

Colorectal Neoplasms

Gastrointestinal Neoplasms

Intestinal Neoplasms

Digestive System Neoplasms

Patients will be examined with Conventional Colonoscopy (CC)

Patients will be examined with Magentiq Eye Assisted Colonoscopy (MEAC)

Patients in Group A (CC) will undergo Screening or Surveillance Conventual Colonoscopy, Patients in Group B (MEAC) will undergo Screening or Surveillance Colonoscopy with ME-ADPS Device

Screening or Surveillance Conventionall colonoscopy

Peter Siersema, MD, Ph.D.

ME-APDS is a device (software-based with hardware) developed by Magentiq Eye LTD and intended to support the decision of the endoscopist on polyps which appear in the colonoscopy video during the colonoscopy procedure.

This randomized two arm colonoscopy trial will mainly compare APC and APE between Magentiq Eye Assisted Colonoscopy (MEAC) and Conventional Colonoscopy (CC) in patients referred for either screening or surveillance colonoscopies.

The primary objective of the present study is to compare the number of Adenomas Per Colonoscopy (APC) and the Adenomas Per Extraction (APE) between the Magentiq Eye-Assisted Colonoscopy (MEAC) and Conventional Colonoscopy (CC). These are also the co-primary endpoints.

The secondary endpoints are Adenoma Miss Rate (AMR, tested on part of the total study population) and Adenoma Detection Rate (ADR).

This study mainly hypothesizes that more adenomas will be detected in MEAC compared to CC (higher APC in MEAC compared to CC), and that the reduction of APE in MEAC compared to CC (if there will be a reduction) will be limited.

The study also assumes that AMR will be reduced in MEAC compared to CC and that ADR will increase to some level in MEAC compared to CC.

The study will include 952 subjects . Eligible patients will be randomized in a 1:1 ratio into two groups, group A and B. In group A, patients will be examined with CC. Patients in group B will be examined using MEAC. Immediately after the randomization, a sub-randomization will be performed on whether an immediate second examination (for AMR calculation) will be conducted or not (136 patients will undergo second examination).

The colonoscopy will be performed in accordance with the standard of care of each medical center in either MEAC or CC.

After the colonoscopy procedure patients will be observed at the endoscopy unit until the discharge criteria are met as per the standard clinical protocol of the medical center. After here, they will be discharged by the treating physician.

Study follow-up period will be up to 30-days post-colonoscopy to register (serious) adverse events and it will be in accordance with the standard of care of medical center.

A Study to Evaluate the Safety and Efficacy of the Use of ME-APDS During Colonoscopy

A Randomized Two Arm Multi-Center Study to Evaluate the Safety and Efficacy of the Use of Magentiq Eye's Automatic Polyp Detection System (ME-APDS) During Colonoscopy

Compare the APC of the Magentiq Eye Assisted Colonoscopy (MEAC) with the Conventional Colonoscopy (CC)

Magentiq Eye LTD

Diseases and Abnormalities at or Before Birth

Nutritional and Metabolic Diseases

Syndrome

Carcinoma

Colorectal Neoplasms, Hereditary Nonpolyposis

Neoplastic Syndromes, Hereditary

Gastrointestinal Diseases

Colonic Diseases

Intestinal Diseases

Genetic Diseases, Inborn

DNA Repair-Deficiency Disorders

Metabolic Diseases

After the caecum is reached patients will be first examined with high definition i-scan endoscopy. Each colonic segment will be investigated in a back to back fashion, during the second pass white light will be used.

After the caecum is reached patients will be first examined with high definition white light endoscopy. Each colonic segment will be investigated in a back to back fashion, during the second pass i-scan will be used.

Prior the colonoscopy patients will be randomized to white light first or i-scan first. After the caecum is reached patients will be first examined according to the randomization. Each colonic segment will be investigated in a back to back fashion, during the second pass the other modality will be used.

The use of I-scan in the detection of polyps in HNPCC

Raf Bisschops, MD PhD

Hereditary non-polyposis colon carcinoma (HNPCC or Lynch-Syndrome) is a rare cause of colorectal cancer caused by a gene defect in the so -called mismatch repair genes. Patients can present at young age with colorectal cancer and polyps can develop faster to malignant lesions in comparison to classical sporadic adenomas. New advanced imaging modalities with high definition images and virtual chromoendoscopy have a theoretical advantage to improve detection and to increase polyp detection. In patients with HNPCC polyp detection has been shown to be increased by classical chromo-endoscopy and by high definition endoscopy with narrow band imaging (NBI) (a virtual chromo-endoscopy modality activated by a button on the endoscope), in comparison to white light endoscopy. However, in these back-to-back studies there was no randomization for the order of imaging modality. It is therefore not clear whether really the image enhancement adds to increased polyp detection or if this is achieved by a second inspection of the mucosa. In this trial the investigators want to assess the real additional value of virtual chromo-endoscopy for polyp detection in patients with the Lynch syndrome. The investigators will use the high definition pentax system and will compare white light endoscopy to i-scan, the incorporated virtual chromo-endoscopy mode in this system.

Hereditary non-polyposis colon carcinoma (HNPCC) or the Lynch syndrome is a rare cause of colorectal cancer caused by a defect in mismatch repair genes. Because of this, colorectal cancer does not develop according to the classical adenoma-carcinoma sequence, resulting in faster progression to malignant lesions. As a results patients typically present at a younger age with colorectal cancer or associated cancers such as endometrium or ovarian cancer. The risk for cancer in patients with the Lynch syndrome has been estimated to be 60-90% for colon cancer presenting at a mean age of 44 years . Colonoscopy is considered the gold standard for polyp detection. However the polyp miss rate has been reported to be 2% for larger adenomas (\< 10mm) , 13% for lesions between 5 and 10 mm and up to 26% for small lesions (1-5 mm). Between 2 to 6 percent of carcinomas can be missed , resulting interval cancers. Typically, in HNPCC small colorectal lesions can already harbor cancer or high grade dysplasia, making early detection of small lesions even more clinically relevant than in an average risk population.

New endoscopic imaging systems that are currently available have a high definition video signal and have an incorporated feature of virtual chromoendoscopy. High definition endoscopy is becoming the new gold standard in endoscopy, since it is available in all new types of commercially available endoscopes. The use of high definition endoscopy may lead to improved recognition of subtle and flat lesions. Furthermore, the use of filters techniques accentuates superficial changes in the mucosal architecture and helps to characterize polyps. I-scan is a postprocessing filter incorporated in the high definition processor (EPKi) of the new Pentax endoscopes. The techniques highlights changes in surface and vessel architecture through 3 different modifications (so called surface enhancement, tone enhancement and contrast enhancement). In a randomized trial in patients with a positive feces occult blood test it has been shown that the system detects significantly more polyps than standard resolution white light.

Current literature suggests that classical chromoendoscopy with indigocarmine (Huneberg, lecomte) or narrow-band imaging (NBI) increases the detection of polyps in HNPCC patients. Although all of these studies had a cross-over design, randomization for the imaging modality was either not possible (in case of chromoendoscopy) or not applied (in case of NBI). So it is not clear whether more polyps are detected by advanced imaging techniques, or simply by a second inspection of the colon.

The aim of this study was to assess the additional value of i-scan in polyp detection in HNPCC patients in comparison to high definition white light endoscopy (HD-WLE) in a randomized controlled cross-over trial. The investigators also wanted to investigate the effect of a second inspection round on polyp detection.

I-Scan For Colon Polyp Detection In HNPCC

High Definition Endoscopy Versus Virtual Chromoendoscopy In The Detection Of Colonic Polyps In HNPCC

Universitaire Ziekenhuizen KU Leuven

Inclusion criteria were as follows: Patients older than 18 years, with a complete colonoscopy, for CRC screening or post-polypectomy surveillance or diagnostic assessment. Exclusion criteria precluded patients with previous colectomy or an abdominal surgery in the last 6 months, patients with polyposis syndromes or inflammatory bowel diseases and if they were unfit for polypectomy or the polyp specimen was not retrieved for histology.

Prospective evaluation of an every day technique (retroflexion) used in our department for many years. The protocol of ascending colon examination encompassed 2 phases: A first phase (1) divided in Forward view (1a) videlicet insertion from the right flexure to the caecum followed by a second forward view (1b) namely withdrawal till the right flexure and reinsertion to the caecum maintaining the endoscope straight and a second phase (2, Retroflexion) with U-turn of the colonoscope in the caecum till the right flexure and then redressing to the forward view and reinsertion to the caecum.

Retroflexion in the Right Colon

Missing polyps during colonoscopy is considered an important factor for interval cancer appearance especially in the ascending colon (AC). Aim of the study: To evaluate the contribution of retroflexion to adenoma detection in the AC. Patients-Methods: Prospective observational study included consecutive patients with complete colonoscopy between June 2017 and June 2018. The AC was examined in two phases. The first phase included two forward views from the hepatic flexure to the cecum and the second phase a retroflexion in the cecum, inspection till the hepatic flexure then redressing to forward view and reinsertion to the cecum.

We prospectively evaluated for polyp detection in the ascending colon a cohort of consecutive patients addressed (intended) for complete colonoscopy in Alexandra University Hospital, Athens, Greece for a predetermined period (June 2017-June 2018). All colonoscopies were performed under conscious sedation by using midazolam and/or propofol and continuous monitoring for vital signs. The type of endoscopes used were adult high definition, with variable stiffness, colonoscopes Olympus Evis Exera CF-H185 and 190. Insufflation was performed by means of a CO2 insufflator (OLYMPUS - UCR). An irrigation pump (OLYMPUS - OFP2) was used if needed, either for washing or for water exchange technique according to the endoscopist judgement. Oral sodium and potassium sulphate in combination (Eziclen®) or PEG solutions (Klean Prep® or Fortrans®) were used for bowel preparation which was measured by means of the Segmental Boston Bowel Preparation Scale. Inclusion criteria were as follows: Patients older than 18 years, with a complete colonoscopy, for CRC screening or post-polypectomy surveillance or diagnostic assessment. Exclusion criteria precluded patients with previous colectomy or an abdominal surgery in the last 6 months, patients with polyposis syndromes or inflammatory bowel diseases and if they were unfit for polypectomy or the polyp specimen was not retrieved for histology. The protocol of ascending colon examination encompassed 2 phases: A first phase (1) divided in Forward view (1a) videlicet insertion from the right flexure to the caecum followed by a second forward view (1b) namely withdrawal till the right flexure and reinsertion to the caecum maintaining the endoscope straight and a second phase (2, Retroflexion) with U-turn of the colonoscope in the caecum till the right flexure and then redressing to the forward view and reinsertion to the caecum.

Concerning endoscopy 2 seniors and 4 trainees participated in the study. All colonoscopies were performed with at least 2 operators, one senior and one trainee. The main investigator, the most experienced endoscopist in the department was present during all the procedures for the ascending colon examination (SM). Only 3 attempts were permitted for retroflexion achievement, performed by the main investigator if a younger trainee or senior gastroenterologist could not perform it. Polyps were mapped during both phases and were not removed until the end of the inspection. Polypectomy followed according to the previous mapping and all polyps were collected and sent for histological examination. The protocol of this non-interventional study as well as the informed consent for the patients were submitted and approved by the local ethical committee.

Adenoma detection rate (ADR) was defined as the number of colonoscopies in which one or more adenomas were detected, divided by the total number of colonoscopies. ADR in the ascending colon as the number of colonoscopies with at least one adenoma in the ascending colon divided by the total number of colonoscopies. Adenoma miss rate (AMR) of the ascending colon was defined as the number of additional adenomas in ascending colon detected by retroflexed view divided by the total adenomas in ascending colon detected with two forward and retroflexion views. The per-patient miss rate was calculated as the number of patients with additional adenomas detected on retroflexion divided by the total number of patients who underwent the examination.

Finally we evaluated two additional quality parameters in order to assess the contribution of retroflexion in adenoma detection: adenomas per colonoscopy (APC) calculated by dividing the number of detected adenomas by the total number of colonoscopies and adenomas per positive participant (APP) calculated by dividing the number of detected adenomas by the number of colonoscopies in which at least 1 adenoma was detected.

Retroflexion In The Ascending Colon Is A Costless Endoscopic Maneuver Increasing Adenoma Detection Rate

adenoma miss rate by performing systematically a retroflexion after a second forward view in the ascending colon and evaluate the additional gain in adenoma detection

Study title	NCT ID	Conditions	Interventions	Eligibility	Organization
Impact of SE of the Proximal Colon on the AMR	NCT05712304	Adenoma Miss Ra...	second examinat...	40 Years - 75 Years	Third People's Hospital of Jingdezhen City
Effect of Water Exchange Method on Adenoma Miss Rates in Patients Undergoing Selective Polypectomy	NCT02880748	Adenoma	Water exchange ... Air insufflatio...	18 Years - 80 Years	Air Force Military Medical University, China
Effect of Water Exchange Method on Adenoma Miss Rates in Patients Undergoing Selective Polypectomy	NCT02880748	Adenoma	Water exchange ... Air insufflatio...	18 Years - 80 Years	Air Force Military Medical University, China
Adenoma Miss Rate With Water Exchange vs Carbon Dioxide Colonoscopy	NCT03832322	Colonic Adenoma Water Exchange ...	Water exchange ... CO2 insufflatio...	20 Years - 75 Years	Evergreen General Hospital, Taiwan
9 Minutes for Tandem Colonoscopy Withdrawal	NCT04797065	Colon Polyp Colorectal Aden...	6-minute then 9... 9-minute then 6...	40 Years - 75 Years	Changhai Hospital
Impact of SE of the Proximal Colon on the AMR	NCT05712304	Adenoma Miss Ra...	second examinat...	40 Years - 75 Years	Third People's Hospital of Jingdezhen City
Impact of SE of the Proximal Colon on the AMR	NCT05712304	Adenoma Miss Ra...	second examinat...	40 Years - 75 Years	Third People's Hospital of Jingdezhen City
A Study to Evaluate the Safety and Efficacy of the Use of ME-APDS During Colonoscopy	NCT04640792	Screening Colon... Surveillance Co...	Screening or Su...	18 Years - 90 Years	Magentiq Eye LTD
Adenoma Miss Rate With Water Exchange vs Carbon Dioxide Colonoscopy	NCT03832322	Colonic Adenoma Water Exchange ...	Water exchange ... CO2 insufflatio...	20 Years - 75 Years	Evergreen General Hospital, Taiwan
Adenoma Miss Rate With Water Exchange vs Carbon Dioxide Colonoscopy	NCT03832322	Colonic Adenoma Water Exchange ...	Water exchange ... CO2 insufflatio...	20 Years - 75 Years	Evergreen General Hospital, Taiwan
I-Scan For Colon Polyp Detection In HNPCC	NCT01823471	Hereditary Non-... HNPCC Lynch Syndrome	The use of I-sc...	18 Years -	Universitaire Ziekenhuizen KU Leuven
Impact of SE of the Proximal Colon on the AMR	NCT05712304	Adenoma Miss Ra...	second examinat...	40 Years - 75 Years	Third People's Hospital of Jingdezhen City
Retroflexion In The Ascending Colon Is A Costless Endoscopic Maneuver Increasing Adenoma Detection Rate	NCT04086706	Colonoscopy Adenoma Detecti... Adenoma Miss Ra... Retroflexion	Retroflexion in...	18 Years -	Alexandra Hospital, Athens, Greece

Spots Global Cancer Trial Database for adenoma miss rate