Rapat Pittayanon

Flexible spectral imaging color enhancement plus probe-based confocal laser endomicroscopy for gastric intestinal metaplasia detection

Probe‐based confocal laser endomicroscope (pCLE) has been applied for the early detection and confirmation of many gastrointestinal neoplasms; however, its use in gastric intestinal metaplasia (GIM) detection has not yet been validated. The objective of this study was to assess the diagnostic yield of magnifying flexible spectral imaging color enhancement (ME‐FICE) plus pCLE for GIM detection.

Helicobacter pylori Infection in Thailand: A Nationwide Study of the CagA Phenotype

Background The risk to develop gastric cancer in Thailand is relatively low among Asian countries. In addition, the age-standardized incidence rate (ASR) of gastric cancer in Thailand varies with geographical distribution; the ASR in the North region is 3.5 times higher than that in the South region. We hypothesized that the prevalence of H. pylori infection and diversity of CagA phenotype contributes to the variety of gastric cancer risk in various regions of Thailand. Methods We conducted a nationwide survey within Thailand. We determined H. pylori infection prevalence by detecting H. pylori, using histochemical and immunohistochemical methods. The anti-CagA antibody and anti-East-Asian type CagA antibody (α-EAS Ab), which showed high accuracy in several East Asian countries, were used to determine CagA phenotype. Results Among 1,546 patients from four regions, including 17 provinces, the overall prevalence of H. pylori infection was 45.9% (710/1,546). Mirroring the prevalence of H. pylori infection, histological scores were the lowest in the South region. Of the 710 H. pylori-positive patients, 93.2% (662) were immunoreactive with the anti-CagA antibody. CagA-negative strain prevalence in the South region was significantly higher than that in other regions (17.9%; 5/28; p < 0.05). Overall, only 77 patients (11.6%) were immunoreactive with the α-EAS Ab. There were no differences in the α-EAS Ab immunoreactive rate across geographical regions. Conclusions This is the first study using immunohistochemistry to confirm H. pylori infections across different regions in Thailand. The prevalence of East-Asian type CagA H. pylori in Thailand was low. The low incidence of gastric cancer in Thailand may be attributed to the low prevalence of precancerous lesions. The low incidence of gastric cancer in the South region might be associated with the lower prevalence of H. pylori infection, precancerous lesions, and CagA-positive H. pylori strains, compared with that in the other regions.

The Learning Curve of Gastric Intestinal Metaplasia Interpretation on the Images Obtained by Probe-Based Confocal Laser Endomicroscopy

Background. Reading the results of gastric intestinal metaplasia (GIM) with probe-based confocal laser endomicroscopy (pCLE) by the expert was excellent. There is a lack of study on the learning curve for GIM interpretation. Therefore, we conducted a study to explore the learning curve in the beginners. Material and Method. Five GI fellows who had no experience in GIM interpretation had been trained with a set of 10 pCLE video clips of GIM and non-GIM until they were able to interpret correctly. Then they were asked to interpret another 80 video clips of GIM and non-GIM. The sensitivity, specificity, accuracy, PPV, NPV, and interobserver agreement on each session were analyzed. Results. Within 2 sessions, all beginners can achieve 80% accuracy with substantial to almost perfect level of interobserver agreement. The sensitivities and specificities among all interpreters were not different statistically. Four out of five interpreters can maintain their high quality of reading skill. Conclusion. After a short session of training on GIM interpretation of pCLE images, the beginners can achieve a high level of reading accuracy with at least substantial level of interobserver agreement. Once they achieve the high reading accuracy, almost all can maintain their high quality of reading skill.

Role of digital chromoendoscopy and confocal laser endomicroscopy for gastric intestinal metaplasia and cancer surveillance

In Japan and countries such as South Korea and Taiwan, China, the standard technique for detecting early gastric cancer (EGC) is chromoendoscopy. This technique involves a magnified endoscope and the use of an indigo-carmine spray to distinguish between EGC and non-EGC areas. However, this technique is not widely adopted in many parts of the world. One important reason for limited use is that this technique needs an experienced endoscopist to interpret the images during the procedure. In addition, the sensitivity for detecting gastric intestinal metaplasia (GIM), a precancerous lesion of EGC, is graded as suboptimal. Moreover, the requirement of a cumbersome spraying method is inconvenient and needs preparation time. Easier digital chromoendoscopy techniques, such as Narrow-band Imaging and Flexible spectral Imaging Color Enhancement, have been reported to facilitate targeted GIM and EGC biopsy. They provide higher sensitivities over conventional white light endoscopy. Recently, the novel technology of confocal laser endomicroscopy has been introduced as a high-magnification (1000 ×) real-time evaluation for many early gastrointestinal (GI) cancers and precancerous GI lesions, including colonic polyp, Barretts esophagus, and GIM. The advantage of this technique is that it can be used as an in vivo confirmation of the presence of GIM and EGC during endoscopic surveillance. This review aims to explain the current information on the usefulness of digital chromoendoscopy and confocal laser endomicroscopy for evaluating GIM and EGC during endoscopic surveillance and the possible future role of these techniques for GI cancer screening programs.

The Secondary Quality Indicator to Improve Prediction of Adenoma Miss Rate Apart from Adenoma Detection Rate.

Objectives:Adenoma detection rate (ADR) cannot distinguish between endoscopists who detect one adenoma and those who detect ≥2 adenomas. Hypothetically, adenoma miss rate (AMR) may be significant for endoscopists with high ADRs who examine the rest of colon with less care after detecting first polyp. Our objective was to evaluate other quality indicators plus ADR vs. ADR alone in prediction of AMR.Methods:We conducted a cross-sectional study of asymptomatic participants aged 50–75 years who underwent back-to-back screening colonoscopies by four faculty endoscopists. Each round of colonoscopy was performed by two of the endoscopists in a randomized order. During each round of colonoscopy, all detected polyps were removed. The second endoscopist was blinded to the results of the first. The total number of adenomas per positive participant (APP), the total number of adenomas per colonoscopy (APC), the additional adenomas found after the first adenoma per colonoscopy (ADR-Plus), and ADR were calculated for prediction of AMR.Results:In all, 200 participants underwent back-to-back colonoscopies. There were no significant differences in ADRs of four endoscopists (44, 50, 54, and 46%). APPs were 1.91, 2.12, 2.19, and 2.43. APCs were 0.84, 1.06, 1.18, and 1.12. ADR-Plus were 0.40, 0.56, 0.64, and 0.66, respectively. AMRs differed significantly between the endoscopists (36, 27, 21, and 13%; P=0.01). There was no correlation between ADR and AMR (r=−0.25; P=0.75). Whereas APP exhibited a strong inverse correlation with AMRs (r=−0.99; P<0.01). APC and ADR-Plus appeared to be inversely correlated with AMR, however this was not statistically significant (r=−0.82; P=0.18 and r=−0.93; P=0.07, respectively).Conclusions:Among high-ADR endoscopists, AMRs still varied. APP may be a promising secondary indicator for distinguishing between the one-and-done polyp endoscopist and the meticulous endoscopist. The evaluation of influence of new metrics on colorectal cancer (CRC) prevention requires a larger population-based study.

Endoscopic ultrasound-guided needle-based confocal laser endomicroscopy for diagnosis of solid pancreatic lesions (ENES): a pilot study

Background and study aims: Endoscopic ultrasound-guided needle-based confocal laser endomicroscopy (EUS-nCLE) has been shown to aid in the diagnosis of cystic pancreatic lesions. This is a pilot project to study its findings in patients with solid pancreatic lesions (SPLs) with a prospective single-blinded study design. Methods: Patients with SPLs undergoing trans-gastric EUS fine needle aspiration (EUS-FNA) from July 2013 to March 2014 were prospectively enrolled. The nCLE diagnoses were compared with the final diagnoses. Researchers learned about the EUS-nCLE findings from previously published studies and applied it to diagnose SPLs. In the meantime, the findings were recorded. Results: In total, 22 patients were recruited (mean age 62.7 years, SD 13.8 years; 14 men and eight women). The mean maximal tumor diameter was 36.0 mm (SD 10.9 mm). EUS-nCLE yielded satisfactory images in all patients during the first EUS procedure and diagnosed benign and malignant SPLs in 3 and 19 patients, respectively. Final diagnoses of malignant SPLs were made in 19 patients. Benign SPLs were eventually diagnosed in three patients, with confirmed the cytology and disease stability during the 12-month follow-up period. At the end of the project, based on the results of this current study, EUS-nCLE findings for malignant SPLs were dark clumping with or without dilated vessels (> 40 μm). There were two criteria for diagnosing benign lesions which were white fibrous bands and normal acini cells. The accuracy rate of EUS-nCLE was 90.9 % (20/22). One falsely diagnosed malignant SPL was an inflammatory mass from a recent acute pancreatitis. Another one with a pancreatic neuroendocrine tumor presenting with a symptomatic pseudocyst was incorrectly diagnosed as an inflammatory mass. This was likely from sampling error of the EUS-nCLE probe in an inflammatory area. Only one patient had post EUS-FNA bleeding but did not require a blood transfusion. The inter-observer agreement among three blinded endoscopists was almost perfect (Kappa 0.82). Conclusion: EUS-nCLE is a promising technique for the diagnosis of SPLs with good inter-observer agreement. Study registration‎: TCTR20140402001

A multicenter randomized comparison between high-definition white light endoscopy and narrow band imaging for detection of gastric lesions.

Objective Narrow band imaging (NBI) is generally considered to be useful for lesion characterization, but not enhanced detection of gastric lesions, because of the dark endoscopic view. We tested whether the new generation of NBI (190-NBI or 290-NBI), which is twice as bright as the previous version, would improve detection of premalignant gastric lesions compared with high-definition white light endoscopy (HD-WLE). Patients and methods This was a multicenter prospective randomized study involving five tertiary institutions in the Asia-Pacific region. A total of 579 patients aged older than 50 years who underwent diagnostic upper gastrointestinal endoscopy were randomized to either HD-WLE or NBI. The outcome measurements were detection of intestinal metaplasia (IM), focal gastric lesions, and gastric cancers. Results Focal gastric lesions were detected in 83/286 (29%) and 119/293 patients (40.6%) by HD-WLE and by NBI, respectively (P=0.003). IM was detected in 22/286 patients (7.7%) by HD-WLE and in 52/293 patients (17.7%) by NBI (P<0.001). Gastric cancer were found in 7/286 (2.4%) and 3/293 patients (1%) in HD-WLE and NBI groups, respectively (P=0.189). Conclusion NBI increased the detection rate of IM compared with HD-WLE.

Advances in diagnostic endoscopy for duodenal, including ampullary, adenoma.

Currently, the strategy for real‐time endoscopic diagnosis of duodenal, including ampullary, adenoma is still unclear. In the era of high‐definition and magnification endoscopy, using this modality for the detection and diagnosis of these neoplasms is very challenging for endoscopists. Over the past 10 years, many instruments have been developed to improve the detection rate of duodenal and ampullary polyps and to distinguish between adenoma and non‐adenoma. The present review will focus on these novel methods and their usefulness in the diagnosis of ampullary and non‐ampullary adenoma.

Value of probe-based confocal laser endomicroscopy (pCLE) and dual focus narrow-band imaging (dNBI) in diagnosing early squamous cell neoplasms in esophageal Lugol’s voiding lesions

Background and study aims: Lugol’s chromoendoscopy provides excellent sensitivity for the detection of early esophageal squamous cell neoplasms (ESCN), but its specificity is suboptimal. An endoscopy technique for real-time histology is required to decrease the number of unnecessary biopsies. This study aimed to compare the ESCN diagnostic capability of probed-based confocal laser endomicroscopy (pCLE) and dual focus narrow-band imaging (dNBI) in Lugol’s voiding lesions. Patients and methods: Patients with a history of head and neck cancer without dysphagia were recruited. Lugol’s voiding lesions larger than 5 mm were sequentially characterized by dNBI and pCLE by two independent operators. Finally, all lesions larger than 5 mm were biopsied followed by histological analysis, which is considered to be the gold standard in cancer diagnosis. The primary outcomes were the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the accuracy of the two techniques. Results: In total, 44 patients were enrolled with a mean age of 60 years; 80 % were male. Twenty-one Lugol’s voiding lesions larger than 5 mm were detected in 12 patients. Seven lesions (33 %) from four patients were histologically diagnosed as ESCNs (four with high grade dysplasia and three with low grade dysplasia). The other 14 lesions were histologically confirmed as non-neoplastic: active esophagitis, glycogenation with inflammation, acute ulcer, inlet patch, and unremarkable changes. The sensitivity, specificity, PPV, NPV, and accuracy of pCLE vs. dNBI were 83 % vs. 85 %, 92 % vs. 62 %, 83 % vs. 54 %, 92 % vs. 89 %, and 89 % vs. 70 %, respectively (NS). Conclusions: Asymptomatic patients with a history of head and neck cancer underwent Lugol’s chromoendoscopy based ESCN surveillance. Further characterization of the Lugol’s voiding lesions by advanced imaging showed that both pCLE and dNBI provided good sensitivity in diagnosing ESCN, and pCLE tended to provide higher specificity, PPV, and accuracy than dNBI. Perhaps the trend of lower specificity of dNBI in this study was possibly because of the interference from Lugol’s stain on the interpretation of intrapapillary capillary loops (IPCLs). Further study is required to seek a significant difference in the performance of dNBI and pCLE in a larger group of patients.

Diagnostic values of dual focus narrow band imaging and probe-based confocal laser endomicroscopy in FAP-related duodenal adenoma

Background and study aims: Familial adenomatous polyposis (FAP) is associated with an increased risk of development of periampullary and nonampullary adenoma. Either routine biopsy or endoscopic removal of the lesion is generally required to identify the presence of adenoma. Because the risk of tissue sampling from the ampulla is high and nonampullary polyps are sometimes numerous, resection of all the lesions is time-consuming. This study aimed to evaluate the diagnostic values of duodenal adenoma by dual focus NBI (dNBI) and probe-based confocal endomicroscopy (pCLE) in FAP patients. Patients and methods: The authors conducted a diagnostic study in a single tertiary-care referral center. Surveillance esophagogastroduodenoscopy with dNBI and pCLE was performed on 26 patients with FAP for real-time adenoma diagnosis by two different endoscopists; one used dNBI and the other pCLE. Histology from the matched lesion was used as the gold standard. Results: A total of 55 matched biopsies (25 ampullas, 30 nonampullas) were performed. The sensitivity, specificity, post predictive value (PPV), negative predictive value (NPV), and accuracy of dNBI vs. pCLE from all duodenal lesions were 96.9 % vs. 93.8 %, 78.3 % vs. 81 %, 86.1 % vs. 88.2 %, 94.7 vs. 89.5 %, and 92.4 % vs. 88.6 %, respectively. Conclusions: For surveillance of periampullary and nonampullary adenoma in patients with FAP, the real-time readings provided a high degree of diagnostic value when histology was used as the gold standard. (Clinical trial registration number: NCT02162173).