Systematic review with meta-analysis: the long-term efficacy of Barrett's endoscopic therapy-stringent selection criteria and a proposal for definitions

BACKGROUND

Barrett's endoscopic therapy (BET) is well established for neoplasia in Barrett's oesophagus using a concept of complete eradication of all Barrett's. However, long-term efficacy is not known.

AIMS

To perform a systematic review and meta-analysis to examine long-term efficacy of BET for Barrett's neoplasia.

METHODS

Electronic databases were searched for studies meeting stringent criteria: (a) subjects with high-grade dysplasia and/or superficial adenocarcinoma who underwent BET (ablation ± endoscopic mucosal resection); (b) BET completion by confirmation of complete eradication of neoplasia (CE-N) and intestinal metaplasia (CE-IM) with systematic sampling and (c) clearly defined follow-up (endoscopy and biopsy) protocol of ≥2 years thereafter for detection of recurrence. Pooled estimates of CE-N and CE-IM after BET completion and follow-up were analysed.

RESULTS

Eight studies met the stringent criteria (n = 794, males 89%, age 64.6 years). Despite high efficacy of BET at therapy completion (CE-N: 95.9 [91.7-98.7]%; CE-IM: 90.9 [83-96.6]%), this declined (CE-N: 89 [73.4-98.2]%; CE-IM: 77.8 [65.6-88]%) over 3.4 years of follow-up. There was considerable heterogeneity. Only two studies reported a post-BET follow-up of >5 years (CE-IM 50 [41.5%-58.5]%). Higher person years of follow-up seem to correlate with decrease in BET efficacy.

CONCLUSION

Using stringent criteria for appropriate study selection with sufficient follow-up, a lack of high-quality controlled intervention trials becomes evident for assessment of long-term durable remission rates of BET despite initial high success rates. We plea for a uniform documentation of study details which could be used in future trials.

Diagnostic accuracy of a novel third generation esophageal capsule as a non-invasive detection method for Barrett's esophagus: A pilot study

BACKGROUND AND AIM

Previous two generations of esophageal capsule did not show adequate detection rates for Barrett's esophagus (BE). We assessed the diagnostic accuracy of a novel third generation capsule with an improved frame rate of 35 frames per second for the detection of BE in a pilot study.

METHODS

This was a blinded prospective pilot study conducted at a tertiary medical center. Patients with known BE (at least C0M > 1) who presented for endoscopic surveillance (May to October 2017) were included. All patients underwent novel esophageal capsule (PillCam™ UGI; Medtronic) ingestion using the simplified ingestion protocol followed by standard high-definition upper endoscopy (esophagogastroduodenoscopy [EGD]). Capsule endoscopy findings were interpreted by examiners blinded to endoscopy results and compared with endoscopic findings (gold standard). Following completion of both tests, a subjective questionnaire was provided to all patients regarding their experience.

RESULTS

Twenty patients (95%males, mean age 66.3 [±7.9] years) with BE undergoing surveillance EGD were eligible. The mean BE length was 3.5 (±2.7) cm. Novel esophageal capsule detected BE in 75% patients when images were compared with endoscopy. Novel capsule detected BE in 82% patients when the BE length was ≥2 cm. The mean esophageal transit time was 0.59 s. On a subjective questionnaire, all 20 patients reported novel capsule as being more convenient compared with EGD.

CONCLUSIONS

In this pilot, single-center study, novel esophageal capsule was shown to be not ready for population screening of BE. Studies integrating artificial intelligence into improved quality novel esophageal capsule should be performed for BE screening.

Risk of Colorectal Cancer and Cancer Related Mortality After Detection of Low-risk or High-risk Adenomas, Compared With No Adenoma, at Index Colonoscopy: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

The risk of metachronous colorectal cancer (CRC) among patients with no adenomas, low-risk adenomas (LRAs), or high-risk adenomas (HRAs), detected at index colonoscopy, is unclear. We performed a systematic review and meta-analysis to compare incidence rates of metachronous CRC and CRC-related mortality after a baseline colonoscopy for each group.

METHODS

We searched the PubMed, Embase, Google Scholar, and Cochrane databases for studies that reported the incidence of CRC and adenoma characteristics after colonoscopy. The primary outcome was odds of metachronous CRC and CRC-related mortality per 10,000 person-years of follow-up after baseline colonoscopy for all the groups.

RESULTS

Our final analysis included 12 studies with 510,019 patients (mean age, 59.2 ± 2.6 years; 55% male; mean duration of follow up, 8.5 ± 3.3 years). The incidence of CRC per 10,000 person-years was marginally higher for patients with LRAs compared to those with no adenomas (4.5 vs 3.4; odds ratio [OR], 1.26; 95% CI, 1.06-1.51; I²=0), but significantly higher for patients with HRAs compared to those with no adenoma ( 13.8 vs 3.4; odds ratio [OR], 2.92; 95% CI, 2.31-3.69; I²=0 ) and patients with HRAs compared to LRAs (13.81 vs 4.5; OR, 2.35; 95% CI, 1.72-3.20; I²=55%). However, the CRC-related mortality per 10,000 person-years did not differ significantly for patients with LRAs compared to no adenomas (OR, 1.15; 95% CI, 0.76-1.74; I²=0) but was significantly higher in persons with HRAs compared with LRAs (OR, 2.48; 95% CI, 1.30-4.75; I²=38%) and no adenomas (OR, 2.69; 95% CI, 1.87-3.87; I²=0).

CONCLUSIONS

The results of this systematic review and meta-analysis demonstrate that the risk of metachronous CRC and mortality is significantly higher for patients with HRAs, but this risk is very low in patients with LRAs, comparable to patients with no adenomas. Follow-up of patients with LRAs detected at index colonoscopy should be the same as for persons with no adenomas.

Proton pump inhibitors do not increase the risk of dementia: a systematic review and meta-analysis of prospective studies

Published studies have reported variable results on the association between duration of proton pump inhibitor (PPI) use and the risk of dementia. An extensive literature search was performed in PubMed, Embase, Google Scholar, and Cochrane for studies examining the risk of cognitive decline and dementia among PPI users versus non-PPI users in prospective studies. Retrospective database linkage studies, case reports, case series, editorials, uncontrolled cohort studies, cross-sectional studies, and review articles were excluded. Primary outcome was pooled hazard rate (HR) of any dementia among PPI users compared with non-PPI users. Secondary outcomes were pooled HR of Alzheimer's dementia (AD) and risk with long-term PPI follow-up (more than 5 years) studies. Meta-analysis outcomes, heterogeneity (I2), and meta-regression (for the effect of covariates) were derived by statistical software R and Open meta-analyst. A total of six studies (one RCT and five prospective) with 308249 subjects, average age of 75.8 ± 5.2 years, and follow-up of 5 (range 1.5-11) years were included in the analysis. Pooled HR of any dementia was 1.16 (n = 6, 95% confidence interval (CI) = 0.86-1.47). Results remained unchanged when only studies with long-term PPI use (more than 5 years) were analyzed (n = 4, pooled HR 1.10, 95% CI 0.66-1.53). Finally, the pooled HR for AD was 1.06 (n = 3, 95% CI 0.70-1.41). There was substantial heterogeneity among inclusion studies (I2 = 93%). Meta-regression did not demonstrate a significant role of age at study start (P = 0.1) or duration of PPI use (P = 0.62) to incident dementia. The results of this systematic review and meta-analysis do not show a significant relationship between PPI use and dementia in prospective studies with at least a 5-year follow-up.

Efficacy and Safety of Endoscopic Resection of Sessile Serrated Polyps 10 mm or Larger: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

The best method for endoscopic resection of sessile serrated polyps (SSP) 10 mm or larger is unclear; studies report variable outcomes in comparison to conventional adenomas. We performed a systematic review and meta-analysis to assess the efficacy and safety of resection of SSPs 10 mm or larger in size.

METHODS

We searched the PubMed/MEDLINE, Google Scholar, Embase, and Cochrane databases for studies reporting data on endoscopic resection of SSPs 10 mm or larger, through May 31st, 2019. The primary outcome was rate of residual SSP, which was the rate of residual SSP found at the polypectomy site during the first follow-up colonoscopy. Secondary outcomes were: technical success (rate of complete macroscopic resection), R0 resection rate (complete histological resection with absence of any polyp tissue at the lateral and deep margins after en-bloc resection), and adverse events (immediate or delayed bleeding and perforation). We performed IQR,group analyses for outcomes based on polyp size and resection techniques. Pooled proportion rates (%) or odds ratio with 95% CIs with heterogeneity (I²) and P < .05.

RESULTS

A total of 14 studies met the inclusion criteria: 911 patients (50.2% male; mean age, 62.8 ± 4.9 years) who underwent resection of 1137 SSPs (574 SSPs ≥ 20 mm) with a median polyp size of 19.4 mm (interquartile range, 15.9-29.6 mm). Follow-up information was available for 832 SSPs with a median follow-up duration of 12 months (interquartile range, 6-22.5 months). Piecemeal resection was performed in 58.5% SSPs. The pooled residual SSP rate was 4.3% (95% CI, 2%-6.5%). There was a higher residual SSP rate for polyps ≥ 20 mm compared to 10-19 mm (5.9% vs 1.2%; odds ratio, 3.02; 95% CI, 1-9.2; P = .049). Cold endoscopic mucosal resection (EMR) had significantly lower rates of delayed bleeding (0 vs 2.3%; P = .03) and residual polyp rate (0.9% vs 5%; P=.01) compared to hot EMR, based on univariate analysis. In multi-variate analysis there was no difference in residual polyp rate. There was no significant difference in other outcomes based on the size or method of resection.

CONCLUSIONS

In a systematic review and meta-analysis, we found that SSPs ≥ 10 mm can be safely resected with low residual polyp rates. Polyp size ≥ 20 mm is a significant factor for residual polyp. Compared to hot EMR, cold EMR is associated with a lower rate of delayed bleeding. Randomized controlled trials comparing hot and cold resection are needed to standardize techniques and optimize outcomes.

Endoscopic resection reduces morbidity when compared to surgery in veterans with large and complex colorectal polyps

INTRODUCTION

Data supporting endoscopic resection (ER) over surgical resection (SR) for large and complex polyps come from high-volume centers. The aim of this study was to determine whether these favorable outcomes can be replicated among endoscopists at tertiary Veterans Affairs Medical Centers (VAMCs) who perform 25 to 30 ER cases a year.

METHODS

Patients with adenomatous polyps or intra-mucosal cancers ≥ 2 cm in size who underwent ER or SR were identified from prospectively maintained databases at the 2 tertiary VAMCs in Veterans Integrated Service Network 6 (VISN6). The primary outcome was the rate of serious complications in the ER and SR groups.

RESULTS

310 ER and 81 SR patients met the inclusion criteria. ER was successful in 97% of all polyps, and 93% of polyps ≥ 4 cm. The rate of serious complications was significantly lower with ER compared to SR (0.6% vs. 22%, p = 0.00001). These findings persisted even after limiting the analysis to polyps ≥ 4 cm and after propensity score matching. If all ER patients had instead undergone laparoscopic surgery, the estimated risk of a serious complication was still higher than ER for all patients (8% vs. 0.6%, p < 0.0001) but not significantly higher for polyps ≥ 4 cm (8% vs 2%, p = 0.17).

CONCLUSIONS

This study documents high success rates for ER in veterans with colorectal polyps ≥ 2 cm and ≥ 4 cm. When compared to a historical cohort of surgical patients, a strategy of attempting ER first reduced morbidity. A randomized trial is warranted to compare ER to laparoscopic surgery for polyps ≥ 4 cm.

Accuracy of probe-based confocal laser endomicroscopy (pCLE) compared to random biopsies during endoscopic surveillance of Barrett's esophagus

BACKGROUND

 For surveillance of Barrett's esophagus (BE), the current standard of random 4-quadrant biopsies misses 10 - 50 % of esophageal neoplasms, and does not permit real-time decision-making. Probe-based confocal laser endomicroscopy (pCLE) permits real-time in vivo histologic assessment of esophageal mucosa during upper endoscopy. Prospective studies comparing the accuracy of pCLE to 4-quadrant biopsies in routine clinical practice are lacking.

METHODS

 Consecutive patients with BE underwent high definition white light and narrow-band imaging followed by pCLE and targeted biopsy or mucosal resection. Four-quadrant biopsies were obtained during the same session. Baseline variables, real-time pCLE interpretation, and histology results were prospectively recorded. Blinded expert review of pCLE sequences and histology specimens was performed. A sample size of 64 patients was calculated a priori based on 3 % estimated prevalence of high grade dysplasia (HGD) or cancer.

RESULTS

 In total, 66 patients were included in the study. The prevalence of HGD or cancer was 4.55 %. Both real-time and blinded pCLE correctly identified all cases of cancer. For the primary outcome, real-time pCLE was 98 % specific but only 67 % sensitive for HGD/cancer compared to non-blinded pathologist interpretation. For HGD and cancer, inter-observer agreement was substantial between real-time and blinded endomicroscopists (kappa = 0.6). pCLE identified dysplasia in 75 % of cases where both blinded and unblinded pathology interpretation was low grade dysplasia.

CONCLUSIONS

 pCLE demonstrates high specificity for detecting dysplasia and cancer, but lower sensitivity may limit its utility in routine BE surveillance. pCLE may have a role in confirming LGD in real-time before eradication therapy.

Manipulator Configurations Based on Rotary-Linear (R-L) Actuators and Their Direct and Inverse Kinematics

In this paper, a new type of two-degree-of-freedom actuator called the rotary-linear (R-L) actuator is described. The R-L actuator permits a rotation and a translation along the axis of rotation, thus simulating a cylinder pair. The R-L actuators are then used in type synthesis of mechanical manipulator chains. Closed-loop three-, four, five, and six-degree-of-freedom chains containing four to nine links, R-L actuators, revolute pairs (R), prismatic pairs (P), cylindrical pairs (C), and spheric pairs (S) are then obtained. A class of manipulator configurations where the hand is connected to the ground via six-degree-of-freedom dyads or triads and containing three grounded R-L actuators is treated for inverse kinematics. Since all the actuators are on the ground in this configuration, higher payload capacities and smaller actuator sizes can be expected from these configurations. In addition, generally, the computations required for inverse kinematics are also significantly less than those required for serial link open-loop manipulators. The direct kinematics, however, is much more involved and computationally intensive for these manipulators than for serial-link manipulators. The direct kinematics of an example manipulator is derived and requires solution of a 16th-order polynomial equation. Numerical examples are presented for illustration.

Workspace Analysis of Mechanical Manipulators Using Polynomial Discriminants

A new method, for the investigation of manipulator workspace, based on polynomial displacement equations and their discriminants is proposed in this paper. The approach followed enables one to obtain (a) analytical expressions describing the workspace boundary surfaces in Cartesian coordinates, (b) the distribution of the number of ways to position the hand inside the workspace, and (c) the conditions on kinematic parameters when the motion of the hand degenerates. Joint limitations are incorporated in the method. In the present paper and a companion paper [17], the method is rigorously applied to eight types of manipulators with various combinations of revolute and prismatic pairs having the last three revolute axes intersect orthogonally at at point. A numerical example is presented for illustration.

Workspace Analysis of Regional Structures of Manipulators

The fundamental equations for conducting workspace analysis of a class of manipulators having the last three revolute joint axes intersect orthogonally at a point are provided in this paper. These equations are intended for application of the basic theory given in [1] and are concisely arranged in tables. Several examples are included illustrating the use of the tables and equations for determining (a) the boundary surfaces, (b) the surfaces separating the regions of different order of accessibility, and (c) the boundaries due to joint motion limitation.

Elastodynamic Analysis of a Completely Elastic System

The completely elastic system considered for this vibration analysis consists of an offset slider-crank mechanism having (a) elastic supports and mountings of the mechanism permitting translational vibrations of the shafts and supports, (b) elastic shafts permitting torsional vibrations, (c) elastic links of the mechanism which deform due to external or internal body forces and allow flexural and axial vibrations. Both the effect of the deformations caused by the inertia forces in the mechanism links, shafts, and supports and the effect of change in the inertia forces due to these deformations are taken into account in constructing a general mathematical model for conducting elastodynamic analysis. The rigid displacements (finite and infinitesimal) of the mechanism links due to deformations in the support are evaluated using a truncated Taylor series approximation. Deformation in the links caused by the inertia forces is approximated by a finite number of terms in a Fourier series using the Raleigh-Ritz method. The Lagrange equations of motion are used to obtain coupled time varying linear ordinary differential equations of motion for the vibration analysis of the slider-crank mechanism. The method in general may be applied to any planar or spatial system consisting of elastic links, elastic shafts, and elastic supports. Numerical examples are presented for illustration.