Proximal retroflexion versus second forward view of the right colon during screening colonoscopy: A multicentre randomized controlled trial

Excellent Bowel Preparation Quality Is Not Superior to Good Bowel Preparation Quality for Improving Adenoma/Polyp Detection Rate

Background

Adequate bowel preparation quality is essential for high-quality colonoscopy according to the current guidelines. However, the excellent effect of bowel preparation on adenoma/polyp detection rate (ADR/PDR) remained controversial.

Methods

During the period from December 2020 to August 2022, a total of 1566 consecutive patients underwent colonoscopy by an endoscopist. Their medical records were reviewed. According to the Boston bowel preparation scale, patients were divided into excellent, good, and poor bowel preparation quality groups. ADR/PDR, diminutive ADR/PDR, small ADR/PDR, intermediate ADR/PDR, large ADR/PDR, and number of adenomas/polyps were compared among them. Logistic regression analyses were performed to identify the factors that were significantly associated with ADR/PDR.

Results

Overall, 1232 patients were included, of whom 463, 636, and 133 were assigned to the excellent, good, and poor groups, respectively. The good group had a significantly higher ADR/PDR (63% vs 55%, P = .015) and a larger number of adenomas/polyps (2.5 ± 3.2 vs 2.0 ± 2.8, P = .030) than the poor group. Both ADR/PDR (63% vs 55%, P = .097) and number of adenomas/polyps (2.2 ± 2.8 vs 2.0 ± 2.8, P = .219) were not significantly different between excellent and poor groups. The excellent (9% vs 4%, P = .045) and good (9% vs 4%, P = .040) groups had a significantly higher intermediate ADR/PDR than the poor group. Logistic regression analyses showed that either good (odds ratio [OR] = 1.786, 95% CI = 1.046-3.047, P = .034) or excellent (OR = 2.179, 95% CI = 1.241-3.826, P = .007) bowel preparation quality was independently associated with a higher ADR/PDR compared with poor bowel preparation quality. Excellent (OR = 1.202, 95% CI = 0.848-1.704, P = .302) bowel preparation quality was not independently associated with a higher ADR/PDR compared with good bowel preparation quality.

Conclusions

The pursuit of excellence in bowel preparation does not show an association with increased ADR/PDR and number of adenomas/polyps compared with a good level. In addition, our study further contributes to the existing evidence that poor bowel preparation compromises ADR/PDR and number of adenomas/polyps.

Improving polyp detection at colonoscopy: Non-technological techniques

Colonoscopy and polypectomy remain the gold standard investigation for the detection and prevention of colorectal cancer. Halting the progression of colonic adenoma through adequate detection of pre-cancerous lesions interrupts the progression to carcinoma. The adenoma detection rate is a key performance indicator. Increasing adenoma detection rates are associated with reducing rates of interval colorectal cancer. Endoscopists with high baseline adenoma detection rate have a meticulous technique during colonoscopy withdrawal that improves their adenoma detection. This minireview article summarizes the evidence on the following simple operator techniques and their effects on the adenoma detection rate; minimum withdrawal times, dynamic patient position change and proximal colon retroflexion.

Findings in the distal and proximal colon in colonoscopy screening after positive FIT and related pre-procedure factors

BACKGROUND

Colonoscopy is the gold standard method for the early diagnosis and prevention of colorectal cancer (CRC). Screening programs include immune determination of blood in feces. Regardless of the method used, proximal colon lesions appear to be detected less frequently.

OBJECTIVE

Analyze the characteristics of proximal and distal lesions and possible predisposing factors.

METHODS

A cross-sectional study was performed of 692 patients from the CRC screening program with FIT ≥ 100ngHb/ml (October 2017 - October 2018). The right colon was examined twice as patients were participating in a randomized clinical trial to re-evaluate the right colon by forward-viewing endoscope or proximal retroflexion. The adenoma detection rate (ADR), advanced neoplasia (AN) and CRC in the proximal and distal colon, the histological and morphological characteristics in each section were analyzed.

RESULTS

52.9% of the patients were male, with a mean age of 59.5 years (SD: 7.6). 1490 polyps were found and the ADR was 57.7% (distal 42% and proximal 37%). Detection rates were 45.8% for AN, 40.9% for advanced adenomas, 5.2% for advanced SSL and CRC was diagnosed in 4.8% of patients. Males had more AN than females. The mean age of patients with AN was significantly higher. AN were associated with smoking and alcohol consumption (p=0.0001). Globally, FIT levels were higher in patients with AN (p=0.003). Sixty-six per cent of cancers were distally located and 61.3% of CRC were diagnosed in the early stages.

CONCLUSIONS

In an average-risk asymptomatic population undergoing colonoscopy after positive FIT, AN were more common in the distal colon in males, older patients, smokers and those with alcohol intake.

Second exam of right colon improves adenoma detection rate: Systematic review and meta-analysis of randomized controlled trials

Background and study aims  A second examination of the right colon, either as a second forward view (SFV) or as retroflexion (RF) in the cecum, can increase adenoma detection rate (ADR) in the right colon. In this meta-analysis, we have evaluated the role of a second examination of the right colon in improving ADR. Methods  We reviewed several databases to identify randomized controlled trials that compared right colon SFV with no SFV, and RCTs that compared SFV with RF in the right colon, and reported data on ADR. Our outcomes of interest were ADR and polyp detection rate (PDR) with SFV vs no SFV, right colon and total withdrawal times, and additional ADR and PDR with SFV vs RF. For categorical variables, we calculated pooled risk ratios (RRs) with 95 % confidence intervals (CIs); for continuous variables, we calculated standardized mean difference (SMD) with 95 % CI. Data were analyzed using random effects model. Results  We included six studies with 3901 patients. Comparing SFV with no SFV, right colon ADR and PDR were significantly higher in the SFV group: ADR (RR [95 % CI] 1.39 [1.22,1.58]) and PDR (RR [95 % CI] 1.47 [1.30, 1.65]). We found no significant difference in right colon withdrawal time (SMD [95 % CI] 1.54 [-0.20,3.28]) or total withdrawal time (SMD (95 % CI) 0.37 [-0.39,1.13]) with and without SFV. We found no significant difference in additional ADR between SFV and RF. Conclusions  SFV of the right colon significantly increases right-sided and overall ADR.

Factors affecting colorectal adenoma detection rate

Colorectal cancer is a kind of malignant tumors that seriously threatens the health of Chinese people, and its morbidity and mortality rank third and fifth among malignant tumors in China, respectively. High-quality colonoscopy is an effective means of preventing colorectal cancer. Adenoma detection rate (ADR) is defined as the proportion of those who have adenomas in the total number of patients undergoing colonoscopy. With the increase of ADR, the incidence rate and mortality rate of colorectal cancer gradually decrease. Previous studies have found that ADR is affected by many factors. In this paper, we describe the factors that affect ADR from the aspects of colonoscopy, doctors, and equipment, with a purpose to strengthen the understanding of endoscopists on ADR and to increase ADR during colonoscopy.

Two vs One Forward View Examination of Right Colon on Adenoma Detection: An International Multicenter Randomized Trial

BACKGROUND & AIMS

Second forward view (SFV) examination of the right colon (RC) in colonoscopy was suggested to improve the adenoma detection rate (ADR), but multicenter data to inform its routine use remain limited. We performed an international multicenter randomized trial comparing SFV vs a standard single forward view examination of the RC on adenoma detection.

METHODS

Asymptomatic individuals undergoing screening or surveillance colonoscopies from 6 Asia Pacific regions were invited for study. A forward view examination of the RC was first performed in all patients, followed by randomization at the hepatic flexure to either SFV examination of the RC and standard withdrawal examination from the hepatic flexure to rectum, or a standard withdrawal colonoscopy (SWC) examination from the hepatic flexure to rectum. The primary outcome was RC ADR.

RESULTS

Between 2016 and 2019, there were 1011 patients randomized (SFV group, 502 patients; SWC group, 509 patients). Forty-five endoscopists performed the colonoscopies. The RC ADR was significantly higher in the SFV group than in the SWC group (27.1% vs 21.6%; P = .042). The whole-colon ADR was high in both groups (49.0% vs 45.0%; P =.201). The SFV examination identified 58 additional adenomas in 49 patients (9.8%), leading to a change in surveillance recommendations in 15 patients (3.0%). The median overall withdrawal time was 1.5 minutes longer in the SFV group (12.0 vs 10.5 min; P < .001). Older age, male sex, ever smoking, and longer RC withdrawal time were independent predictors of right-sided adenoma detection.

CONCLUSIONS

In this multicenter trial, SFV examination significantly increased the RC ADR in screening and surveillance colonoscopies. Routine RC SFV examination should be considered. ClinicalTrials.gov ID: NCT03121495.

Yield of a second right colon examination during colonoscopy after a first examination using a mucosal exposure device

BACKGROUND AND AIMS

Double right colon examination during colonoscopy has been advocated to reduce the risk of interval cancer in the right colon. Whether 2 examinations are necessary when the first examination is performed with a mucosal exposure device is uncertain. We documented the rates of missed adenomas, sessile serrated lesions, and hyperplastic polyps after an initial right colon examination by a high-level detector using a mucosal exposure device.

METHODS

At a single tertiary hospital outpatient practice, we prospectively collected data on the yield of a second examination of the right colon after an initial examination by a single high-detecting colonoscopist using a mucosal exposure device.

RESULTS

During the study period, 1331 eligible consecutive patients underwent colonoscopy. Right colon adenoma, sessile serrated lesion, and hyperplastic polyp miss rates were 15.8%, 14.1%, and 16.7%, respectively. Four percent of patients had adenomas detected in the right colon only with a second examination.

CONCLUSIONS

A second examination of the right colon is warranted, even when using a distal mucosal exposure device to perform colonoscopy.

Retroflexed view for reexamination of the right colon after forward view examination: Systematic review and meta-analysis

BACKGROUND

The effect of retroflexed view (RV) for the reexamination of the right colon after forward view (FV) examination has not been fully understood.

METHODS

We searched multiple databases including PubMed, Embase, and the Cochrane Library for prospective studies exploring the role of RV for reexamination of the right colon. A meta-analysis was performed on outcomes including lesion detection rates, lesion miss rates, and withdrawal time.

RESULTS

Four randomized controlled trials aimed to compare the impact of the second withdrawal from the right colon in RV vs. FV following a standard colonoscopy. Both the additional adenoma detection rate (AADR) and additional polyp detection rate (APDR) of the right colon were lower in the RV group compared with the FV group (risk ratio [RR] 0.73 for AADR; RR 0.76 for APDR); similar results were noted in comparisons of the adenoma miss rate and polyp miss rate. Six prospective cohort studies aimed to describe the effect of the RV examination of the right colon after one or two rounds of FV examination. Both the adenoma detection rate (ADR) and polyp detection rate (PDR) of the right colon were slightly higher in combined examinations with RV examination than single FV examination (RR 1.11 for ADR; RR 1.16 for PDR) or two FV examinations (RR 1.21 for ADR; RR 1.22 for PDR).

CONCLUSIONS

FV may detect more adenomas and polyps than RV during the second withdrawal from the right colon. RV may detect additional adenomas and polyps in the right colon after two FV examinations.

Updates, Controversies, and Emerging Approaches in Colorectal Screening

Colorectal cancer (CRC) is the third most common cancer worldwide and the second leading cause of cancer-related deaths. Despite the threatening statistics, the US burden for CRC has been decreasing, which is likely multifactorial and has partial contribution from widespread timely screening, more advanced CRC treatment, and daily aspirin use in some patients. While overall death rate from CRC decreased by approximately a half between 1975 and 2012, epidemiologic studies demonstrate that CRC incidence is increasing in the younger population. This pattern has prompted the American Cancer Society (ACS) to revise their guidelines. In this review, we plan to discuss the most recent changes in guidelines, data to support them, controversies concerning CRC screening methods, age to start and to stop screening, and post-colonoscopy/polypectomy surveillance guidelines.

Serrated lesions: A challenging enemy

The serrated pathway accounts for 30%-35% of colorectal cancer (CRC). Unlike hyperplastic polyps, both sessile serrated lesions (SSLs) and traditional serrated adenomas are premalignant lesions, yet SSLs are considered to be the principal serrated precursor of CRCs. Serrated lesions represent a challenge in detection, classification, and removal–contributing to post-colonoscopy cancer. Therefore, it is of the utmost importance to characterize these lesions properly to ensure complete removal. A retrospective cohort study developed a diagnostic scoring system for SSLs to facilitate their detection endoscopically and subsequent removal. From the study, it can be ascertained that both indistinct border and mucus cap are essential in both recognizing and diagnosing serrated lesions. The proximal colon poses technical challenges for some endoscopists, which is why high-quality colonoscopy plays such an important role. The indistinct border of some SSLs poses another challenge due to difficult complete resection. Overall, it is imperative that gastroenterologists use the key features of mucus cap, indistinct borders, and size of at least five millimeters along with a high-quality colonoscopy and a good bowel preparation to improve the SSL detection rate.

Diagnostic value of novel retroflexion colonoscopy in the right colon: A randomized controlled trial

BACKGROUND

Colonoscopy is the accepted gold standard for the detection of colorectal cancer. However, colonoscopy is less effective in preventing colon cancer in the right side compared with the left side.

AIM

To investigate the feasibility of a novel type of retroflexion colonoscope, EC-3490Ti colonoscope, for detection of proximal colon lesions.

METHODS

In this prospective trial, we recruited patients who underwent colonoscopy for screening or surveillance. When the endoscopists could not grasp the whole observation of the right-side colon mucosa in the forward view (FV), insertion and withdrawal were repeatedly performed in the FV group with the EC38-i10F colonoscope while retroflexion was performed in the retroflexed view (RV) group with the EC-3490Ti colonoscope. Adenoma detection rate, the total number of adenomas per positive participant, the success rate of retroflexion, and endoscope withdrawal time were recorded and compared.

RESULTS

The total adenoma detection rate (39.3% vs 37.7%, P = 0.646) did not show any significant difference between the two groups. However, the polyp detection rate (59.6% vs 51.0%, P = 0.002), adenoma detection rate in the right colon (21.6% vs 14.4%, P = 0.012), and the total number of adenomas per positive participant (2.1 vs 1.7, P = 0.011) reached statistical significance. Retroflexion was achieved in 91.7% of our cohort. Compared with the FV group, the withdrawal time was significantly prolonged in the RV group (586.1 ± 124.4 s vs 508.8 ± 129.6 s, P < 0.001). In contrast, the proportion of additional ancillary pressure decreased (27.4% vs 45.7%, P < 0.001), and the visual analog scale pain scores did not increase (2.7 ± 1.4 vs 2.8 ± 1.4, P = 0.377).

CONCLUSION

Retroflexion in the proximal colon could be performed successfully and safely with the EC-3490Ti colonoscope. This maneuver could detect more adenomas effectively.