Characterization of lesions in the stomach: will confocal laser endomicroscopy replace the pathologist?

Confocal laser endomicroscopy as a new diagnostic tool for poorly differentiated gastric adenocarcinoma

Gastric cancer (GC) is a multifactorial disease, where both environmental and genetic features can have an impact on its occurrence and development. GC represents one of the leading causes of cancer-related deaths worldwide. GC is most frequent in males and is believed to arise from a series of premalignant lesions. The detection of GC at an early stage is crucial because early GC, which is an invasive stomach cancer confined to the mucosal or submucosal lining, may be curable with a reported 5-year survival rate of more than 90%. Advanced GC usually has a poor prognosis despite current treatment standards. The diagnostic efficacy of conventional endoscopy (with light endoscopy) is currently limited. Confocal laser endomicroscopy is a novel imaging technique that allows real-time in vivo histological examination of mucosal surfaces during endoscopy. Confocal laser endomicroscopy may be of great importance in the surveillance of precancerous gastric lesions and in the diagnosis of GC. In this editorial we commented on the article about this topic published by Lou et al in the recent issue of the World Journal of Clinical Cases.

Toward next-generation endoscopes integrating biomimetic video systems, nonlinear optical microscopy, and deep learning

According to the World Health Organization, the proportion of the world's population over 60 years will approximately double by 2050. This progressive increase in the elderly population will lead to a dramatic growth of age-related diseases, resulting in tremendous pressure on the sustainability of healthcare systems globally. In this context, finding more efficient ways to address cancers, a set of diseases whose incidence is correlated with age, is of utmost importance. Prevention of cancers to decrease morbidity relies on the identification of precursor lesions before the onset of the disease, or at least diagnosis at an early stage. In this article, after briefly discussing some of the most prominent endoscopic approaches for gastric cancer diagnostics, we review relevant progress in three emerging technologies that have significant potential to play pivotal roles in next-generation endoscopy systems: biomimetic vision (with special focus on compound eye cameras), non-linear optical microscopies, and Deep Learning. Such systems are urgently needed to enhance the three major steps required for the successful diagnostics of gastrointestinal cancers: detection, characterization, and confirmation of suspicious lesions. In the final part, we discuss challenges that lie en route to translating these technologies to next-generation endoscopes that could enhance gastrointestinal imaging, and depict a possible configuration of a system capable of (i) biomimetic endoscopic vision enabling easier detection of lesions, (ii) label-free in vivo tissue characterization, and (iii) intelligently automated gastrointestinal cancer diagnostic.

Hereditary Gastric and Breast Cancer Syndromes Related to CDH1 Germline Mutation: A Multidisciplinary Clinical Review

E-cadherin (CDH1 gene) germline mutations are associated with the development of diffuse gastric cancer in the context of the so-called hereditary diffuse gastric syndrome, and with an inherited predisposition of lobular breast carcinoma. In 2019, the international gastric cancer linkage consortium revised the clinical criteria and established guidelines for the genetic screening of CDH1 germline syndromes. Nevertheless, the introduction of multigene panel testing in clinical practice has led to an increased identification of E-cadherin mutations in individuals without a positive family history of gastric or breast cancers. This observation motivated us to review and present a novel multidisciplinary clinical approach (nutritional, surgical, and image screening) for single subjects who present germline CDH1 mutations but do not fulfil the classic clinical criteria, namely those identified as-(1) incidental finding and (2) individuals with lobular breast cancer without family history of gastric cancer (GC).

The Probe Based Confocal Laser Endomicroscopy (pCLE) in Locally Advanced Gastric Cancer: A Powerful Technique for Real-Time Analysis of Vasculature

Probe based confocal laser endomicroscopy (pCLE) is an advanced technique which provides imaging of gastrointestinal mucosa at subcellular resolution and, importantly, a valid tool for the evaluation of microvasculature during endoscopic examination. In order to assess intratumoral vascularization and the efficiency of blood flow in locally advanced gastric cancer, we examined 57 patients through pCLE imaging. The vascular alterations in gastric cancer were mainly characterized by leakage and by the presence of tortuous and large size vessels. Defects in blood flow were detected very rarely. No association between the angiogenic score and the gastric tumor site or histological type was observed. Interestingly, no correlation was also found with the tumor grading indicating that the vascular angiogenic anomalies in gastric cancer represent an early pathological event to be observed and detected. The majority of patients displayed unchanged vascular alterations following neoadjuvant chemotherapy and this positively correlated with stable or progressive disease, suggesting that an unaltered angiogenic score could per se be indicative of poor therapeutic efficacy. Different vascular parameters were evaluated by immunofluorescence using bioptic samples and the vessel density did not correlate with clinical staging, site or histologic type. Interestingly, only CD105, Multimerin-2 and GLUT1 were able to discriminate normal from tumoral gastric mucosa. Taken together, these findings indicate that functional and structural angiogenic parameters characteristic of tumor blood network were fully detectable by pCLE. Moreover, the evaluation of tumor vasculature by real-time assessment may provide useful information to achieve tailored therapeutic interventions for gastric cancer patients.

Comparison of diagnostic efficacy between CLE, tissue sampling, and CLE combined with tissue sampling for undetermined pancreaticobiliary strictures: a meta-analysis

OBJECTIVE

The accurate diagnosis of undetermined pancreaticobiliary strictures remains challenging. Current ERCP-guided tissue sampling methods are of low sensitivity. Confocal laser endomicroscopy (CLE) is a new procedure and allows real optical biopsies that may improve the diagnosis of undetermined pancreaticobiliary strictures. The aim of this meta-analysis was to determine the diagnostic yield of CLE, tissue sampling, and CLE combined with tissue sampling for undetermined pancreaticobiliary strictures.

METHOD

Pubmed, Embase, and the Cochrane Library database were reviewed for relevant studies. Pooled estimates of sensitivity and specificity with 95% confidence intervals (CIs) were calculated using the random-effects meta-analysis model. The summary receiver-operating characteristic (SROC) curve was constructed, and the area under the receiver operating characteristic curve (AUC) was calculated.

RESULTS

Twelve studies involving 591 patients were enrolled in our analysis. The overall sensitivity and the specificity estimate of CLE for discriminating benign and malignant pancreaticobiliary strictures were 87% (95%CI, 83-91%) and 76% (95%CI, 70-81%), respectively. The AUC to assess the diagnostic efficacy was 0.8705. For tissue sampling, the overall sensitivity and the specificity estimate were 64% (95%CI, 57-70%) and 94% (95%CI, 90-97%), respectively. The AUC to assess the diagnostic efficacy was 0.8040. A combination of both methods increased the sensitivity (93%; 95%CI, 88-96%) with a specificity of 82% (95%CI, 74-89%). The AUC to assess the diagnostic efficacy was 0.9377. There was no publication bias by Deeks' Funnel Plot with p = .936.

CONCLUSIONS

Compared with tissue sampling, CLE may increase the sensitivity for the diagnosis of malignant pancreaticobiliary strictures. A combination of both can effectively diagnose malignant pancreaticobiliary strictures.

Probe-based confocal laser endomicroscopy for the diagnosis of undetermined biliary stenoses: A meta-analysis

BACKGROUND

Presently, both the accuracy and sensitivity for distinguishing biliary stenosis from benign to malignant are low. In recent articles, the probe-based confocal laser endomicroscopy (pCLE) showed a better sensitivity than traditional methods in diagnosing malignant biliary stenosis. Here, we conducted a meta-analysis to summarise the published literature.

METHODS

A systematic search for literature was conducted in the Medline, Embase and Cochrane Library databases published until November 2015. Further publications were found in the reference lists of the relevant articles. A quality assessment and data extraction were performed by two reviewers independently. A meta-analysis was performed to evaluate the diagnostic efficiency of a pCLE for discriminating benign and malignant biliary stenoses.

RESULTS

Eight studies involving 280 patients were included in the analysis. Significant heterogeneity in specificity was observed among the studies (Cochran's Q test=15.89, degrees of freedom [df]=7, P=0.0261 and I²=55.9%), while the heterogeneity in sensitivity was not obvious (Cochran's Q test=7.99, df=7, P=0.3334 and I²=12.4%). The area under the summary receiver operating characteristic (SROC) curve was 0.8968. The meta-regression and subgroup analysis indicated that the outlier was the source of heterogeneity. When analysed in the random-effects model, the pooled sensitivity, specificity, positive likelihood ratio (LR) and negative LR were 0.90 (0.84-0.94), 0.75 (0.66-0.83), 3.17 (2.18-4.61) and 0.17 (0.11-0.26), respectively. No significant publication bias was found in our research.

CONCLUSION

A pCLE is a valuable method for the differential diagnosis between malignant and benign biliary stenoses. However, a preferable diagnostic standard should be explored and improvements in specificity are required.

Diagnostic of Helicobacter pylori infection

There is progress in endoscopy techniques. While it is not yet possible to detect Helicobacter pylori directly in the stomach, it becomes easier to detect the mucosal changes induced by the bacteria. Some small changes can also increase the sensitivity of the invasive tests, for example culture or histology, but the wide use of proton-pump inhibitors has a negative impact on these tests. Only molecular methods are able to detect a limited load of bacteria, especially by using real-time PCR but also with new methods, for example dual-priming oligonucleotide-based PCR, loop-medicated isothermal amplification, droplet-digital PCR or a multiple genetic analysis system. Among the noninvasive tests, urea breath test remains a test of major interest, while there are attempts to develop an ammonia breath test and other nanosensor devices. A new antigen stool test, a chemoluminescence immunoassay using the LIAISON apparatus has also been tested for the first time with success. Despite its limitations, serology remains the most popular test to detect H. pylori antibodies. It also allows pepsinogen dosage which is of interest for detecting atrophy.