Clutch cutter is a safe device for performing endoscopic submucosal dissection of superficial esophageal neoplasms: a western experience

Although the endoscopic submucosal dissection (ESD) has been established to be more efficacious in the treatment of superficial gastrointestinal neoplasia than the piecemeal resection, its use is still limited due to the concern about serious adverse events particularly in the west. Newer ESD knives have been developed that have been said to be safer than the first-generation devices. We aimed to report a Western single center experience regarding the initial safety and performance of ESD for superficial esophageal neoplasia treated with the Clutch Cutter (DP2618DT; Fujifilm Corporation, Tokyo, Japan). Our main outcome was safety in terms of bleeding or perforation. Secondary outcomes included en bloc resection and the R0 resection. Fourteen patients with superficial esophageal neoplasia underwent 15 ESDs using the Clutch Cutter. The mean age was 65 ± 16.7 years and 10 (71.4%) males. Eight (57%) patients had esophageal adenocarcinoma, 3 (21.4%) had high-grade dysplasia, 1 (7%) had nodular low-grade dysplasia, and 2 (14.3%) had squamous cell carcinoma. Mild anticipated intraprocedural bleeding was present with most procedures. However, no significant postoperative bleeding or perforation was encountered. One patient had mild chest pain postprocedure. En bloc resection was achieved in all lesions 100%. Histological R0 was achieved in 5/12 lesions (41.6%). The mean length of the resected area was 24.8 ± 13 mm (IQR: 17-30 mm). All patients were safely discharged home after overnight observation. In conclusion, this is the largest series of esophageal ESD using the multimodal Clutch Cutter in the United States; we found that the device effectively achieved en bloc resection of superficial esophageal neoplasia without significant adverse events. The use of the Clutch Cutter should be considered as one option to minimize adverse events during ESD in the Western population.

A prospective multicenter study using a new multiband mucosectomy device for endoscopic resection of early neoplasia in Barrett's esophagus

BACKGROUND AND AIMS

Early neoplasia in Barrett's esophagus (BE) can be effectively and safely removed by endoscopic resection (ER) using multiband mucosectomy (MBM). This study aimed to document performance of a novel MBM device designed for improved visualization, easier passage of accessories, and better suction power compared with other marketed MBM devices.

METHODS

This international, single-arm, prospective registry in 14 referral centers (Europe, 10; United States, 3; Canada, 1) included patients with early BE neoplasia scheduled for ER. The primary endpoint was successful ER defined as complete resection of the delineated area in 1 procedure. Secondary outcomes were adverse events and procedure time.

RESULTS

A total of 332 lesions was included in 291 patients (248 men; mean age, 67 years [standard deviation, 9.6]). ER indication was high-grade dysplasia in 64%, early adenocarcinoma in 19%, lesion with low-grade dysplasia in 11%, and a lesion without definite histology in 6%. Successful ER was reached in 322 of 332 lesions (97%; 95% confidence interval [CI], 94.6%-98.4%). A perforation occurred in 3 of 332 procedures (.9%; 95% CI, .31%-2.62%), all were managed endoscopically, and patients were admitted with intravenous antibiotics during days 2, 3, and 9. Postprocedural bleeding requiring an intervention occurred in 5 of 332 resections (1.5%; 95% CI, .65%-3.48%). Dysphagia requiring dilatation occurred in 11 patients (3.8%; 95% CI, 2.1%-6.6%). Median procedure time was 16 minutes (interquartile range, 12.0-26.0).

CONCLUSIONS

In expert hands, the novel MBM device proved to be effective for resection of early neoplastic lesions in BE, with successful ER in 97% of procedures. Severe adverse events were rare and were effectively managed endoscopically or conservatively. (Clinical trial registration number: NCT02482701.).

Volumetric laser endomicroscopy interpretation and feature analysis in dysplastic Barrett's esophagus

BACKGROUND AND AIM

Volumetric laser endomicroscopy (VLE) is used to identify Barrett's esophagus (BE) dysplasia. Selection of a dysplastic region of interest (ROI) can be challenging due to feature variability across a large amount of data. The degree of agreement among VLE users in selecting a ROI has not been studied.

METHODS

High-definition videos that divided a VLE scan from 18 patients with biopsy-proven BE dysplasia into 1-cm segments were reviewed using a four-quadrant grid superimposed for systematic interpretation. VLE scans were selected based on image quality and appropriate visualization of BE epithelium. Four experienced VLE users rated each quadrant as dysplastic or non-dysplastic. For quadrants rated as dysplastic, reviewers selected a single timeframe with representative features. A high-degree of agreement among reviewers was defined as ≥75% agreement on the quadrant diagnosis and ≥50% agreement on selected timeframe (±2 s).

RESULTS

Thirty-one videos, each 32 s in length, comprising 124 quadrants were reviewed. There was high-agreement among reviewers in 99 (80%) quadrants, of which 68 (69%) were rated as dysplastic. Compared with quadrants rated as non-dysplastic, ROIs of quadrants rated as dysplastic contained a higher number of epithelial glands (12.7 vs 1.2, P < 0.001) with atypical architecture (54 vs 1, P < 0.001). A statistically significant difference was observed between the signal intensity profiles of quadrants rated as dysplastic and quadrants rated as non-dysplastic (P = 0.004).

CONCLUSION

This study highlights that experienced VLE users can identify ROIs with high-degree of agreement. Selected ROIs contained VLE features associated with BE dysplasia.

Cryotherapy for persistent Barrett's esophagus after radiofrequency ablation: a systematic review and meta-analysis

BACKGROUND AND AIMS

A small but significant proportion of patients with Barrett's esophagus (BE) have persistent dysplasia or intestinal metaplasia (IM) after treatment with radiofrequency ablation (RFA). Cryotherapy is a cold-based ablative modality that is increasingly being used in this setting. We aimed to better understand the efficacy of second-line cryotherapy in patients with BE who have persistent dysplasia or IM after RFA by conducting a systematic review and meta-analysis.

METHODS

We performed a systematic literature search of Pubmed, EMBASE, and Web of Science through September 1, 2017. Articles were included for meta-analysis based on the following inclusion criteria: ≥5 patients with BE treated with RFA had persistent dysplasia or IM; they subsequently underwent ≥1 session of cryotherapy with follow-up endoscopy; the proportions of patients achieving complete eradication of dysplasia (CE-D) and/or IM (CE-IM) were reported. The main outcomes were pooled proportions of CE-D and CE-IM by using a random effects model.

RESULTS

Eleven studies making up 148 patients with BE treated with cryotherapy for persistent dysplasia or IM after RFA were included. The pooled proportion of CE-D was 76.0% (95% confidence interval [CI] 57.7-88.0), with substantial heterogeneity (I2 = 62%). The pooled proportion of CE-IM was 45.9% (95% CI, 32.0-60.5) with moderate heterogeneity (I2 = 57%). Multiple preplanned subgroup analyses did not sufficiently explain the heterogeneity. Adverse effects were reported in 6.7% of patients.

CONCLUSION

Cryotherapy successfully achieved CE-D in three fourths and CE-IM in half of patients with BE who did not respond to initial RFA. Considering its favorable safety profile, cryotherapy may be a viable second-line option for this therapeutically challenging cohort of patients with BE, but higher-quality studies validating this remain warranted.

Learning curve and competence for volumetric laser endomicroscopy in Barrett's esophagus using cumulative sum analysis

BACKGROUND AND STUDY AIMS

Little is known about the learning curve for image interpretation in volumetric laser endomicroscopy (VLE) in Barrett's esophagus (BE). The goal of this study was to calculate the learning curve, competence of image interpretation, sensitivity, specificity, and accuracy of VLE among novice users.

METHODS

31 novice users viewed 96 VLE images electronically at three academic institutions after a brief training session. There were 24 images of each histologic type: normal gastric cardia, normal esophageal squamous epithelium, non-neoplastic BE, and neoplastic BE. The users were asked to identify the correct tissue type and level of confidence. The cumulative summation (CUSUM) technique was used to construct a learning curve.

RESULTS

22 (71 %) of the physicians achieved VLE interpretation competency during their 96-slide review. Half of the physicians achieved competency at 65 images (95 % confidence interval [CI] 45 - 85). There was a statistically significant association between confidence in diagnosis and selecting the correct histologic tissue type (P < 0.001). The median accuracy for esophageal squamous epithelium, normal gastric cardia, non-neoplastic BE, and neoplastic BE was 96 % (95 %CI 95 % - 96 %), 95 % (95 %CI 94 % - 96 %), 90 % (95 %CI 88 % - 91 %), 96 % (95 %CI 95 % - 96 %). The overall accuracy was 95 % (95 %CI 93 % - 95 %).

CONCLUSION

The majority of novice users achieved competence in image interpretation of VLE for BE, using a pre-selected image set, with a favorable learning curve after a brief training session. An electronic review of VLE images, prior to real-time use of VLE, is encouraged.

Optical coherence tomography in gastroenterology: a review and future outlook

Optical coherence tomography (OCT) is an imaging technique optically analogous to ultrasound that can generate depth-resolved images with micrometer-scale resolution. Advances in fiber optics and miniaturized actuation technologies allow OCT imaging of the human body and further expand OCT utilization in applications including but not limited to cardiology and gastroenterology. This review article provides an overview of current OCT development and its clinical utility in the gastrointestinal tract, including disease detection/differentiation and endoscopic therapy guidance, as well as a discussion of its future applications.

Volumetric laser endomicroscopy in the management of Barrett's esophagus

PURPOSE OF REVIEW

The incidence of esophageal adenocarcinoma is on the rise despite widespread appreciation that the precursor lesion is Barrett's esophagus. Studies have shown that some patients known to have Barrett's esophagus develop cancer despite their enrollment in conventional endoscopic surveillance programs. This highlights the need for advanced endoscopic imaging to help identify early neoplasia and prevent its progression to esophageal cancer. Recently, a wide-field, second-generation optical coherence tomography endoscopic platform called volumetric laser endomicroscopy (VLE) was cleared by the Food and Drug Administration and made commercially available for advanced imaging in Barrett's esophagus.

RECENT FINDINGS

The current review discusses current literature on VLE imaging in Barrett's esophagus. Based on ex-vivo studies, criteria have been established for identifying Barrett's esophagus-associated neoplasia. In addition, recent studies, case series, and case reports have demonstrated that VLE is well tolerated, efficacious, and can target neoplasia.

SUMMARY

VLE is a new advanced imaging platform for Barrett's esophagus with considerable promise to target Barrett's esophagus-associated neoplasia. The following are needed to establish VLE's clinical role: studies showing incremental yield of dysplasia detection using VLE, studies to determine VLE's in-vivo diagnostic accuracy for identifying and classifying Barrett's esophagus-associated neoplasia, and studies on the cost-efficacy of VLE.

Volumetric laser endomicroscopy in Barrett's esophagus: interobserver agreement for interpretation of Barrett's esophagus and associated neoplasia among high-frequency users

BACKGROUND AND AIMS

Targeting neoplasia in Barrett's esophagus (BE) is challenging. Volumetric laser endomicroscopy (VLE) is a new imaging technique that allows for real time cross-sectional microstructure imaging that can detect BE neoplasia. The interobserver agreement among users in practice is unknown.

METHODS

Eight high-volume users of VLE from different academic centers in the United States evaluated 120 stored VLE images blinded to the endoscopic and clinical findings. There were 30 images for each tissue type: gastric cardia, esophageal squamous mucosa, nonneoplastic BE, and neoplastic BE. Each image with BE had corresponding histology confirming the tissue diagnosis. Each normal esophagus and gastric cardia had matching endoscopic images confirming normal mucosa. These were considered the criterion standard. Respondents were asked to classify the images into 1 of each category. Agreement among the users was measured.

RESULTS

The overall agreement among users was almost perfect (kappa = 0.81; 95% confidence interval [CI], 0.79-0.83). For esophageal squamous and gastric cardia, the agreement was almost perfect (kappa 0.95 and 0.86, respectively [95% CI, 0.92-0.98 and 0.83-0.89]). For nonneoplastic BE and neoplastic BE, the agreement was strong (kappa 0.66 [95% CI, 0.63-0.69] and 0.79 [95% CI, 0.75-0.82], respectively). When compared with the criterion standard, the median accuracy for identifying normal squamous mucosa, normal gastric mucosa, nonneoplastic BE, neoplastic BE, and all tissue types was 99% (95% CI, 98%-100%), 97% (95% CI, 95%-99%), 93% (95% CI, 88%-98%), 95% (95% CI, 91%-99%), and 96% (95% CI, 94%-99%), respectively.

CONCLUSIONS

VLE has a high level of agreement and accuracy among high-volume users.

Making Dysphagia Easier to Swallow: A Review for the Practicing Clinician

Evaluating a patient with dysphagia can be a complex and daunting task. In this article, we present a practical approach to the evaluation, physical examination, and subsequent work-up of dysphagia that is applicable to practicing physicians.

Identification of volumetric laser endomicroscopy features predictive for early neoplasia in Barrett's esophagus using high-quality histological correlation

BACKGROUND AND AIMS

Volumetric laser endomicroscopy (VLE) provides a circumferential scan that enables visualization of the subsurface layers of the esophageal wall at 7 μm resolution. The aims of this study were to identify VLE features of Barrett's esophagus (BE) neoplasia and to develop a VLE prediction score.

METHODS

A database of VLE images from endoscopic resection specimens, precisely correlated with histology, from patients with BE with and without neoplasia was used. Features potentially predictive for early BE neoplasia were identified by unblinded evaluation of 25 VLE-histology images. In a learning phase, 20 VLE images with or without BE neoplasia were scored by 2 VLE experts, blinded to histology. A prediction score was created by using multivariable logistic regression analyses and validated by scoring 40 VLE images (50% neoplastic) by using area under receiver operating characteristic (ROC) curve (AUC) analysis.

RESULTS

Three VLE features independently predictive for BE neoplasia were identified: (1) lack of layering; (2) higher surface than subsurface signal; (3) presence of irregular, dilated glands/ducts. A VLE neoplasia prediction score was developed with the following: (1) 6 points; (2) 6 or 8 points for equal or higher surface signal; and (3) 5 points. The ROC curve of this prediction score showed an AUC of 0.81 (95% confidence interval, 0.71-0.90). A cut-off value of ≥8 was associated with sensitivity and specificity of 83% and 71%, respectively.

CONCLUSIONS

When high-quality ex vivo VLE-histology correlation was used, the VLE features of layering, surface signal, and irregular glands/ducts were independently and significantly associated with BE neoplasia. A VLE prediction score for BE neoplasia was developed and validated, with promising accuracy. (Clinical trial registration number: NCT01862666.).

Comparative diagnostic performance of volumetric laser endomicroscopy and confocal laser endomicroscopy in the detection of dysplasia associated with Barrett's esophagus

BACKGROUND AND AIMS

Probe-based confocal laser endomicroscopy (pCLE) and volumetric laser endomicroscopy (VLE) (also known as frequency domain optical coherence tomography) are advanced endoscopic imaging modalities that may be useful in the diagnosis of dysplasia associated with Barrett's esophagus (BE). We performed pCLE examination in ex-vivo EMR specimens and compared the diagnostic performance of using the current VLE scoring index (previously established as OCT-SI) and a novel VLE diagnostic algorithm (VLE-DA) for the detection of dysplasia.

METHODS

A total of 27 patients with BE enrolled in a surveillance program at a tertiary-care center underwent 50 clinically indicated EMRs that were imaged with VLE and pCLE and classified into neoplastic (N = 34; high-grade dysplasia, intramucosal adenocarcinoma) and nonneoplastic (N = 16; low-grade dysplasia, nondysplastic BE), based on histology. Image datasets (VLE, N = 50; pCLE, N = 50) were rated by 3 gastroenterologists trained in the established diagnostic criteria for each imaging modality as well as a new diagnostic algorithm for VLE derived from a training set that demonstrated association of specific VLE features with neoplasia. Sensitivity, specificity, and diagnostic accuracy were assessed for each imaging modality and diagnostic criteria.

RESULTS

The sensitivity, specificity, and diagnostic accuracy of pCLE for detection of BE dysplasia was 76% (95% confidence interval [CI], 59-88), 79% (95% CI, 53-92), and 77% (95% CI, 72-82), respectively. The optimal diagnostic performance of OCT-SI showed a sensitivity of 70% (95% CI, 52-84), specificity of 60% (95% CI, 36-79), and diagnostic accuracy of 67%; (95% CI, 58-78). The use of the novel VLE-DA showed a sensitivity of 86% (95% CI, 69-96), specificity of 88% (95% CI, 60-99), and diagnostic accuracy of 87% (95% CI, 86-88). The diagnostic accuracy of using the new VLE-DA criteria was significantly superior to the current OCT-SI (P < .01).

CONCLUSION

The use of a new VLE-DA showed enhanced diagnostic performance for detecting BE dysplasia ex vivo compared with the current OCT-SI. Further validation of this algorithm in vivo is warranted.

Diagnosing gastrointestinal illnesses using fecal headspace volatile organic compounds

Volatile organic compounds (VOCs) emitted from stool are the components of the smell of stool representing the end products of microbial activity and metabolism that can be used to diagnose disease. Despite the abundance of hydrogen, carbon dioxide, and methane that have already been identified in human flatus, the small portion of trace gases making up the VOCs emitted from stool include organic acids, alcohols, esters, heterocyclic compounds, aldehydes, ketones, and alkanes, among others. These are the gases that vary among individuals in sickness and in health, in dietary changes, and in gut microbial activity. Electronic nose devices are analytical and pattern recognition platforms that can utilize mass spectrometry or electrochemical sensors to detect these VOCs in gas samples. When paired with machine-learning and pattern recognition algorithms, this can identify patterns of VOCs, and thus patterns of smell, that can be used to identify disease states. In this review, we provide a clinical background of VOC identification, electronic nose development, and review gastroenterology applications toward diagnosing disease by the volatile headspace analysis of stool.

Stent-in-stent technique for removal of embedded partially covered self-expanding metal stents

BACKGROUND

Removal of embedded partially covered self-expanding metal stents (PCSEMS) is associated with an increased risk of adverse events compared with removal of fully covered self-expanding stents (FCSES) due to tissue ingrowth. Successful removal of embedded PCSEMS has been described by the stent-in-stent (SIS) technique.

AIMS

To report the first US experience from three high-volume quaternary care centers on the safety and efficacy of the SIS technique for removal of embedded PCSEMS.

METHODS

Retrospective study of outcomes for consecutive patients who underwent the SIS for removal of embedded PCSEMS over a 5-year period.

RESULTS

Twenty-seven embedded PCSEMS were successfully removed using the SIS technique (100 %) from 25 patients (11 males), median age 65 (range 37-80). All stents were successfully removed in one endoscopic session (no repeat SIS procedures were required for persistently embedded stents). The embedded PCSEMS had been in situ for a median of 76 days (range 26-501). Median SIS dwell time (FCSES in situ of PCSEMS) was 13 days (interquartile range 8-16 days; range 4-212 days). One adverse event (self-limited bleeding) occurred during a median follow-up period of 3 months (range 1-32). No patients died, required surgery, or had long-term disability due to adverse events attributed to the SIS technique. Twelve patients required additional interventions following SIS procedure for persistence or recurrence of the underlying pathology.

CONCLUSION

When performed by experienced endoscopists, safe and effective removal of embedded PCSEMS can be achieved via the SIS technique.

Radiofrequency Ablation Is Associated With Decreased Neoplastic Progression in Patients With Barrett's Esophagus and Confirmed Low-Grade Dysplasia

BACKGROUND & AIMS

Barrett's esophagus (BE) with low-grade dysplasia (LGD) can progress to high-grade dysplasia (HGD) and esophageal adenocarcinoma (EAC). Radiofrequency ablation (RFA) has been shown to be an effective treatment for LGD in clinical trials, but its effectiveness in clinical practice is unclear. We compared the rate of progression of LGD after RFA with endoscopic surveillance alone in routine clinical practice.

METHODS

We performed a retrospective study of patients who either underwent RFA (n = 45) or surveillance endoscopy (n = 125) for LGD, confirmed by at least 1 expert pathologist, from October 1992 through December 2013 at 3 medical centers in the United States. Cox regression analysis was used to assess the association between progression and RFA.

RESULTS

Data were collected over median follow-up periods of 889 days (interquartile range, 264-1623 days) after RFA and 848 days (interquartile range, 322-2355 days) after surveillance endoscopy (P = .32). The annual rates of progression to HGD or EAC were 6.6% in the surveillance group and 0.77% in the RFA group. The risk of progression to HGD or EAC was significantly lower among patients who underwent RFA than those who underwent surveillance (adjusted hazard ratio = 0.06; 95% confidence interval: 0.008-0.48).

CONCLUSIONS

Among patients with BE and confirmed LGD, rates of progression to a combined end point of HGD and EAC were lower among those treated with RFA than among untreated patients. Although selection bias cannot be excluded, these findings provide additional evidence for the use of endoscopic ablation therapy for LGD.

Clinical and histologic determinants of mortality for patients with Barrett's esophagus-related T1 esophageal adenocarcinoma

BACKGROUND & AIMS

Superficial (T1) esophageal adenocarcinoma (EAC) commonly is treated by endoscopic resection, yet little is known about factors that predict outcomes of this approach. We assessed clinical and histologic variables associated with the overall survival times of patients with T1 EAC who received therapy.

METHODS

In a retrospective analysis, we collected data from patients who underwent endoscopic mucosal resection (EMR) for T1 EAC (194 patients with T1a and 75 patients with T1b) at the Mayo Clinic, from 1995 through 2011. EMR specimens were reviewed systematically for depth of invasion, presence of lymphovascular invasion, grade of differentiation, and status of resection margins. Kaplan-Meier curves and proportional hazards regression models were used in statistical analyses.

RESULTS

Demographic characteristics were similar between patients with T1a and T1b EAC. Overall survival at 5 years after EMR was 74.4% for patients with T1a (95% confidence interval [CI], 67.6%-81.8%) and 53.2% for patients with T1b EAC (95% CI, 40.3%-70.1%). Of surviving patients with T1a EAC, 94.1% remained free of cancer (95% CI, 89.8%-98.5%), and 94.7% of surviving patients with T1b EAC remained free of cancer (95% CI, 85.2%-100%). A multivariable model associated older age (per 10-year increment), evidence of lymphovascular invasion, and deep margin involvement with reduced overall survival in patients with T1 EAC.

CONCLUSIONS

Systematic assessment of EMR specimens can help predict mortality and potentially guide treatment options for patients with T1 EAC.

Obstructive sleep apnea is a risk factor for Barrett's esophagus

BACKGROUND & AIMS

Common risk factors for obstructive sleep apnea (OSA) and Barrett's esophagus (BE) include obesity and gastroesophageal reflux disease (GERD). The aims of this study were to assess the association between OSA and BE and to determine whether the association is independent of GERD and body mass index (BMI).

METHODS

Patients who had undergone a diagnostic polysomnogram and esophagogastroduodenoscopy were identified by using Mayo Clinic (Rochester, Minnesota) databases from January 2000-November 2011. They were randomly matched for age, sex, and BMI at time of polysomnogram into the following groups: BE but no OSA (n = 36), OSA but no BE (n = 78), both (n = 74), or neither (n = 74). Clinical and demographic variables were abstracted from medical records. The association between OSA and BE was assessed by using a multiple variable logistic model that incorporated age, sex, BMI, clinical diagnosis of GERD, and smoking history.

RESULTS

Subjects with OSA had an 80% increased risk for BE compared with subjects without OSA (odds ratio, 1.8; 95% confidence interval, 1.1-3.2; P = .03). These findings were independent of age, sex, BMI, GERD, and smoking history. Increasing severity of OSA, measured by using the apnea-hypopnea index, was associated with an increased risk of BE (odds ratio, 1.2 per 10-unit increase in apnea-hypopnea index; 95% confidence interval, 1.0-1.3; P = .03).

CONCLUSIONS

In this case-control study, OSA was associated with an increased risk of BE, potentially through BMI and GERD independent mechanisms. Patients with OSA may benefit from evaluation for BE.

Application of confocal laser endomicroscopy in the diagnosis and management of Barrett's esophagus

Confocal laser endomicroscopy is an advanced endoscopic imaging modality that can be used for the diagnosis of early mucosal dysplasia in various gastrointestinal conditions. It provides histology-like images at 1000-fold magnification. The technology offers potential advantages in the diagnosis of Barrett's esophagus and early esophageal cancer due to the low yield of the current practice of surveillance endoscopy with biopsies. Confocal laser endomicroscopy has the potential to eliminate the need for biopsy, establish diagnosis and facilitate application of endoscopic therapy during the time of actual endoscopy. There are several studies that have demonstrated reasonable diagnostic accuracy in patients undergoing surveillance for Barrett's esophagus from tertiary academic medical centers. However, the application of confocal laser endomicroscopy in routine clinical endoscopy is still in the process of refinement. Its role in the diagnosis and treatment of Barrett's-associated dysplasia will continue to evolve with improvement in technology, criteria for diagnosis and experience among endoscopists in interpreting confocal imaging.

Utility of baseline positron emission tomography with computed tomography for predicting endoscopic resectability and survival outcomes in patients with early esophageal adenocarcinoma

BACKGROUND AND AIMS

Positron emission tomography with computed tomography (PET/CT) has been used to detect metastasis in the diagnosis of esophageal adenocarcinoma (EAC). However, the utility of PET/CT to assess primary tumor for endoscopic resectability and prognosis in early EAC remains unclear. We conducted a retrospective study to determine the association of PET/CT findings with histopathological tumor invasion depth and survival outcomes.

METHODS

EAC patients who underwent PET/CT followed by endoscopic mucosal resection (EMR) were included. Pathology on EMR and survival outcomes from a prospectively maintained database was retrieved. Two radiologists independently reviewed the PET/CT using the following parameters: detection of malignancy, fluorodeoxyglucose (FDG) uptake intensity, FDG focality, FDG eccentricity, esophageal thickness, maximal standard uptake value (SUVmax), and SUVmax ratio (lesion/liver).

RESULTS

There were 72 eligible patients: 42 (58.3%) had T1a lesions, and 30 (41.7%) had ≥ T1b. Only SUVmax ratio was associated with tumor invasion depth (odds ratio=2.77, 95% confidence interval 1.26-7.73, P=0.0075). Using a cut-off of 1.48, the sensitivity and specificity of SUVmax ratio for identification of T1a lesions were 43.3% and 80.9%, respectively. Adjusting the SUVmax ratio to 2.14, 16.7% (5/30) of ≥ T1b patients were identified without any false-positive cases. Multivariate analysis showed SUVmax ratio, Charlson comorbidity index, and esophagectomy were independent predictors for survival.

CONCLUSIONS

SUVmax ratio (lesion/liver) is more accurate in predicting endoscopic resectability and mortality for EAC than other PET/CT parameters and appears promising as a useful adjunct to the current diagnostic work-up.

Barrett's esophagus in 2012: updates in pathogenesis, treatment, and surveillance

Barrett's esophagus (BE) is the only established precursor lesion in the development of esophageal adenocarcinoma (EAC) and it increases the risk of cancer by 11-fold. It is regarded as a complication of gastroesophageal reflux disease. There is an ever-increasing body of knowledge on the pathogenesis, diagnosis, treatment, and surveillance of BE and its associated dysplasia. In this review, we summarize the latest advances in BE research and clinical practice in the past 2 years. It is critical to understand the molecular underpinnings of this disorder to comprehend the clinical outcomes of the disease. For clinical gastroenterologists, there is also continuous growth of endoscopic approaches which is daunting, and further improvements in the detection and treatment of BE and early EAC are anticipated. In the future, we may see the increased role of biomarkers, both molecular and imaging, in both diagnostic and therapeutic strategies for BE.

Endoscopic therapy for Barrett's esophagus and early esophageal adenocarcinoma

Endoscopic therapy for Barrett's esophagus is feasible and likely to decrease the future risk of development of esophageal adenocarcinoma. The most commonly used therapy is radiofrequency ablation, which has been shown to produce reproducible superficial injury in the esophagus. Other thermal therapies include multipolar coagulation, argon plasma coagulation, and thermal laser therapy. The other end of the ablative spectrum includes cryotherapy, which involves freezing tissue to produce mucosal necrosis. Photodynamic therapy has been used to photochemically eliminate abnormal mucosa. Endoscopic therapy has been demonstrated to be effective in high-risk situations such as Barrett's esophagus with high-grade dysplasia.

Metabolic syndrome as a risk factor for Barrett esophagus: a population-based case-control study

OBJECTIVES

To assess the association between Barrett esophagus (BE) and the metabolic syndrome in patients with and without reflux symptoms and to determine whether this association is reflux independent and metabolically driven.

PATIENTS AND METHODS

Case patients with BE and controls were residents of Olmsted County, Minnesota (1999-2006). Two control groups (one with and one without symptoms of gastroesophageal reflux) were identified from a cohort of patients who had responded to a validated gastrointestinal symptom questionnaire. Cases and controls were individually matched by age, sex, and duration of follow-up. Controls did not have a known diagnosis of BE. The association of the metabolic syndrome and its individual components with BE was assessed using univariate and multivariate conditional logistic regression separately for each control group.

RESULTS

A total of 309 patients were included (103 BE cases, 103 controls with reflux symptoms, and 103 controls without reflux symptoms). A total of 64% of cases, 47% of controls with reflux symptoms, and 50% of controls without reflux symptoms had the metabolic syndrome. The metabolic syndrome was associated with a 2-fold increased risk of BE relative to those with (odds ratio, 2.00; 95% CI, 1.10-3.65; P=.02) and without (odds ratio, 1.90; 95% CI, 1.03-3.60; P=.04) reflux symptoms. This association was independent of smoking, alcohol consumption, and body mass index and remained robust with sensitivity analysis.

CONCLUSION

The metabolic syndrome is associated with BE independent of reflux symptoms, which may reflect a reflux-independent pathway of BE pathogenesis.

Synergistic effects of photodynamic therapy with HPPH and gemcitabine in pancreatic cancer cell lines

BACKGROUND AND OBJECTIVE

Photodynamic therapy (PDT) is a potential treatment for pancreatic cancer. A second-generation photosensitizer, 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide (HPPH) has a long wavelength absorption, high-tumor selectivity, and shorter duration of skin photosensitivity. We investigated the efficacy of PDT with HPPH and gemcitabine in inducing cell death in multiple pancreatic cancer cell lines.

METHODS

We used three pancreatic cancer cell lines (PANC-1, MIA PaCa-2, and BXPC-3) incubated with HPPH concentration of 0, 0.005, 0.01, 0.025, 0.05, 0.1, 0.25, and 0.5 µg/ml for 6 hours, followed by photoradiation at a light dose of 60 J/cm(2). Afterwards, each cell line was treated with gemcitabine at concentrations of 0, 1, 10, and 100 µM and incubated for another 96 hours. Cell death was detected with SYTOX green staining. We also assessed the difference in cytotoxicity in adding gemcitabine before and after PDT.

RESULTS

HPPH-PDT can effectively induce cell death in all cell lines in a dose-dependent manner, with a 100% of cell death at the 0.5 µg/ml HPPH concentration. In contrast, monotherapy with gemcitabine alone (100 µM) only achieved <45% cell death. Combining gemcitabine to HPPH-PDT resulted in synergistic cytotoxic effect with 20-50% more cell death across all cell lines. There was no difference in cytotoxicity in adding gemcitabine before or after PDT.

CONCLUSION

This is the first study on HPPH-PDT for pancreatic cancer. HPPH-PDT-induced cell death occurs in a dose-dependent manner. HPPH-PDT and gemcitabine have synergistic effects in inducing cell death in multiple pancreatic cancer cell lines.

Diagnostic performance of two confocal endomicroscopy systems in detecting Barrett's dysplasia: a pilot study using a novel bioprobe in ex vivo tissue

BACKGROUND

There are currently 2 existing confocal laser endomicroscopy (CLE) platforms: probe-based CLE (pCLE) and endoscope-based CLE (eCLE) systems, each with its own criteria for identifying dysplasia in Barrett's esophagus (BE). The diagnostic performance of these 2 systems has not been directly compared.

DESIGN

Preclinical, feasibility study.

OBJECTIVES

We compared the interrater agreement and diagnostic performance of the pCLE and eCLE systems. In addition, we evaluated a new BE endomicroscopy criteria based on fluorescent glucose intensity uptake.

PATIENTS

Thirteen patients with Barrett's esophagus and high-grade dysplasia or early cancer undergoing 16 EMR.

INTERVENTION

CLE imaging was performed using two different probes with 2-[N-(7-nitrobenz-2-oxa-1,3-diaxol-4-yl)amino]-2-deoxyglucose, a fluorescent glucose analog with preferential uptake in dysplastic mucosa to supply contrast. Four quadrants were imaged per specimen with a total of 64 imaged mucosal sites presented to three gastroenterologists.

MAIN OUTCOME MEASUREMENTS

Interobserver agreement and accuracy for dysplasia was assessed of images classified according to Miami criteria, stacked eCLE images classified using the Mainz criteria and a novel fluorescence intensity criteria.

RESULTS

The interrater agreements were 0.17, 0.68, and 0.87 for the Miami, Mainz, and the fluorescence intensity criteria, respectively. Overall accuracy in detecting dysplasia was 37% (95% CI, 30.3-43.9), 44.3% (95% CI, 37.3-50.9), and 78.6% (95% CI, 72.2-83.3) for the Miami, Mainz, and the fluorescence intensity criteria, respectively.

LIMITATIONS

This imaging technique and proposed fluorescence intensity criteria using 2-[N-(7-nitrobenz-2-oxa-1,3-diaxol-4-yl)amino]-2-deoxyglucose in EMR tissue will require in vivo validation and cannot be directly used with the current eCLE and pCLE clinical applications.

CONCLUSIONS

In this preclinical feasibility study, the use of an eCLE system with a topical fluorescent contrast in ex vivo EMR tissue demonstrated higher interrater agreement and accuracy.

Photodynamic therapy for unresectable cholangiocarcinoma: a comparative effectiveness systematic review and meta-analyses

BACKGROUND

Photodynamic therapy (PDT) with placement of a biliary stent may improve bile duct patency in patients with cholangiocarcinoma (CCA). We aimed to determine the effectiveness of biliary stenting with PDT compared to biliary stenting alone in the palliative treatment of CCA.

MATERIALS AND METHODS

Several databases were searched from inception to December 2011 for prospective studies comparing biliary stenting with PDT vs. biliary stenting only for CCA. Outcomes of interest included patient survival, quality of life (using Karnofsky score), and serum bilirubin levels. The relative risk (RR) for dichotomous outcomes and the weighted mean difference (WMD) for continuous outcomes were estimated using DerSimonian and Laird random-effects model. Inconsistency was quantified using I(2) statistics. The extent of publication bias was ascertained by visual inspection of funnel plots and Egger's test.

RESULTS

There were six studies that met inclusion criteria. A total of 170 participants received PDT and 157 had biliary stenting only. Compared with biliary stenting, PDT was associated with a statistically significant increase in the length of survival (WMD 265 days; 95% CI: 154-376; p = 0.01; I(2) = 65%), improvement in Karnofsky scores (WMD 7.74; 95% CI: 3.73-11.76; p = 0.01; I(2)= 14%), and a trend for decline in serum bilirubin (WMD -2.92 mg/dL; 95% CI: -7.54 to 1.71; p=0.22; I(2) = 94%). The pooled event rate for biliary sepsis was 15% and was similar between PDT and control groups.

CONCLUSION

Palliative treatment of CCA with PDT is associated with increased survival benefit, improved biliary drainage, and quality of life. However, the quality of this evidence is low.

Meta-analysis of randomized trials comparing the patency of covered and uncovered self-expandable metal stents for palliation of distal malignant bile duct obstruction

BACKGROUND

Self-expandable metal stents (SEMSs) are used for palliation of malignant biliary obstruction.

OBJECTIVE

We performed a meta-analysis to compare stent patency and stent survival of covered SEMSs (CSEMSs) and uncovered SEMSs (USEMSs) in patients with unresectable distal malignant biliary obstruction.

DESIGN

Meta-analysis.

SETTING

Tertiary-care facility.

PATIENTS

A comprehensive search of several databases (from each database's earliest inclusive dates to November 2010, any language, and any population) was conducted. The search identified 337 potential abstracts and titles, of which 16 were retrieved in full text. Review of references identified 17 additional studies. We found 5 multicenter, randomized trials involving 781 patients.

INTERVENTION

Placement of covered and uncovered SEMSs for treatment of distal malignant biliary obstruction.

MAIN OUTCOME MEASUREMENTS

Stent patency, stent survival, patient survival, and cause for stent dysfunction (ingrowth, overgrowth, migration, and sludge formation).

RESULTS

The median length of follow-up was 212 days. Compared with USEMSs, CSEMSs were associated with significantly prolonged stent patency (weighted mean difference [WMD] 60.56 days; 95% confidence interval [CI], 25.96, 95.17; I² = 0%) and longer stent survival (WMD 68.87 days; 95% CI, 25.64, 112.11; I(2) = 79%). Stent migration, tumor overgrowth, and sludge formation were significantly higher with CSEMSs (relative risk [RR] 8.11; 95% CI, 1.47, 44.76; I² = 0%), (RR 2.02; 95% CI, 1.08, 3.78; I² = 0%), (RR 2.89; 95% CI, 1.27, 6.55; I² = 0%).

LIMITATIONS

Relatively low number of studies available and the fact that 2 of the 5 studies were from one institution. Also, the limited availability of some stents used in the trials may limit the applicability of these results.

CONCLUSION

CSEMSs have a significantly longer duration of patency compared with USEMSs in patients with distal malignant biliary obstruction. Stent dysfunction occurs at a similar rate, although there is a trend toward later obstruction with CSEMSs.