Systematic Endoscopic Approach to Early Gastric Cancer in Clinical Practice

An artificial intelligence system for comprehensive pathologic outcome prediction in early gastric cancer through endoscopic image analysis (with video)

BACKGROUND

Accurate prediction of pathologic results for early gastric cancer (EGC) based on endoscopic findings is essential in deciding between endoscopic and surgical resection. This study aimed to develop an artificial intelligence (AI) model to assess comprehensive pathologic characteristics of EGC using white-light endoscopic images and videos.

METHODS

To train the model, we retrospectively collected 4,336 images and prospectively included 153 videos from patients with EGC who underwent endoscopic or surgical resection. The performance of the model was tested and compared to that of 16 endoscopists (nine experts and seven novices) using a mutually exclusive set of 260 images and 10 videos. Finally, we conducted external validation using 436 images and 89 videos from another institution.

RESULTS

After training, the model achieved predictive accuracies of 89.7% for undifferentiated histology, 88.0% for submucosal invasion, 87.9% for lymphovascular invasion (LVI), and 92.7% for lymph node metastasis (LNM), using endoscopic videos. The area under the curve values of the model were 0.992 for undifferentiated histology, 0.902 for submucosal invasion, 0.706 for LVI, and 0.680 for LNM in the test. In addition, the model showed significantly higher accuracy than the experts in predicting undifferentiated histology (92.7% vs. 71.6%), submucosal invasion (87.3% vs. 72.6%), and LNM (87.7% vs. 72.3%). The external validation showed accuracies of 75.6% and 71.9% for undifferentiated histology and submucosal invasion, respectively.

CONCLUSIONS

AI may assist endoscopists with high predictive performance for differentiation status and invasion depth of EGC. Further research is needed to improve the detection of LVI and LNM.

Value of quantitative microsurface structure analysis for evaluating the invasion depth of type 0-II early gastric cancer

Background and Aim

The microsurface structure reflects the degree of damage to the glands, which is related to the invasion depth of early gastric cancer. To evaluate the diagnostic value of quantitative microsurface structure analysis for estimating the invasion depth of early gastric cancer.

Methods

White-light imaging and narrow-band imaging (NBI) endoscopy were used to visualize the lesions of the included patients. The area ratio and depth-predicting score (DPS) of each patient were calculated; meanwhile, each lesion was examined by endoscopic ultrasonography (EUS).

Results

Ninety-three patients were included between 2016 and 2019. Microsurface structure is related to the histological differentiation and progression of early gastric cancer. The receiver operating characteristic curve showed that when an area ratio of 80.3% was used as a cut-off value for distinguishing mucosal (M) and submucosal (SM) type 0-II gastric cancers, the sensitivity, specificity, and accuracy were 82.9%, 80.2%, and 91.6%, respectively. The accuracies for distinguishing M/SM differentiated and undifferentiated early gastric cancers were 87.4% and 84.8%, respectively. The accuracy of EUS for distinguishing M/SM early gastric cancer was 74.9%. DPS can only distinguish M-SM1 (SM infiltration <500 μm)/SM (SM infiltration ≥500 μm) with an accuracy of 83.8%. The accuracy of using area ratio for distinguishing 0-II early gastric cancers was better than those of using DPS and EUS (P < 0.05).

Conclusion

Quantitative analysis of microsurface structure can be performed to assess M/SM type 0-II gastric cancer and is expected to be effective for judging the invasion depth of gastric cancer.

Delayed Perforation Occurring after Gastric Endoscopic Submucosal Dissection: Clinical Features and Management Strategy

Background/Aims

Delayed perforation is a rare but serious adverse event of gastric endoscopic submucosal dissection (ESD). The aim of this study was to clarify the clinical features and appropriate management strategy of patients with delayed perforation.

Methods

Among 11,531 patients who underwent gastric ESD, the clinical features and outcomes of patients who experienced delayed perforation were retrospectively reviewed and compared with those of the control group.

Results

Delayed perforation occurred in 15 of 11,531 patients (0.13%). The patients with delayed perforation were significantly older than those without delayed perforation (p=0.027). The median time to diagnosis of delayed perforation was 28.8 hours (range, 14 to 71 hours). All 15 patients with delayed perforation complained of severe abdominal pain after gastric ESD and underwent subsequent chest X-rays (CXRs) for evaluation. In subsequent CXR, free air was found in 12 patients (80%). For three (20%) patients without free air in CXR, delayed perforation was finally diagnosed by computed tomography. Leukocytosis was significantly less frequent in the patients without free air in CXR (p=0.022). A perforation hole smaller than 1 cm in size was more frequently observed in the six patients who underwent successful non-surgical treatments than in the nine patients who underwent surgery (p<0.001). There was no mortality related to delayed perforation.

Conclusions

One-fifth of the patients with delayed perforation did not show free air in CXR and exhibited less leukocytosis than those with free air. Non-surgical treatments including endoscopic closure might be considered as an initial treatment modality for delayed perforation smaller than 1 cm.

Endoscopic submucosal dissection for early gastric cancer: It is time to consider the quality of its outcomes

Endoscopic resection, particularly endoscopic submucosal dissection (ESD), is widely used as a standard treatment modality for early gastric cancer (EGC) when the risk of lymph node metastasis is negligible. Compared with surgical gastrectomy, ESD is a minimally invasive procedure with additional advantages, such as preservation of the entire stomach and maintenance of the patient's quality of life. However, not all patients achieve curative resection after ESD of EGC. Several patients require surgical gastrectomy after ESD to achieve a curative treatment. Additional surgery after ESD, owing to non-curative resection, places considerable emotional and financial burdens on patients. Recently, as the number of endoscopists performing ESD has increased, the rate of non-curative resection after ESD has increased correspondingly. In order to decrease the non-curative resection rate, as well as determine the ideal rate of non-curative resection after ESD, it is time to consider quality indicators for the outcomes of ESD for EGC.

Texture and color enhancement imaging improves the visibility of gastric neoplasms: clinical trial with image catalogue assessment using conventional and newly developed endoscopes

BACKGROUND

Texture and color enhancement imaging (TXI) enhances the changes in endoscopic features caused by gastric neoplasms, such as redness/whiteness and elevation/depression. This study aimed to demonstrate the effectiveness of TXI in improving the visibility of gastric neoplasms compared with white light imaging (WLI) using conventional (CE) and newly developed endoscopes (NE).

METHODS

We recruited patients who were histologically diagnosed with gastric neoplasms; endoscopy was performed, and gastric neoplasms photographed using three imaging modalities, including WLI, TXI mode 1 (TXI-1) and TXI mode 2 (TXI-2). Two different endoscopes (CE and NE) were used for the same patients. Six endoscopists provided the visibility scale scores ranging from 1 (poor) to 4 (excellent) for gastric neoplasms. The primary outcome was the visibility scale scores based on each modality and endoscope. The secondary outcome was the identification of factors including H. pylori infection, atrophy, location, size, morphology, histological diagnosis and intestinal metaplasia that affect the differences in visibility scale scores between TXI-1/TXI-2 and WLI.

RESULTS

Fifty-two gastric neoplasms were analyzed. The mean visibility scale scores with the NE were 2.79 ± 1.07, 3.23 ± 0.96 and 3.14 ± 0.92 for WLI, TXI-1 and TXI-2, respectively. The mean visibility scales with the CE were 2.53 ± 1.10, 3.04 ± 1.05 and 2.96 ± 1.92 for WLI, TXI-1 and TXI-2, respectively. For both endoscopes, significant differences were observed in visibility scale scores between WLI and TXI-1 (p < 0.001) and between WLI and TXI-2 (p < 0.001). The visibility scale scores of NE were superior to those of CE in all modalities. In the secondary outcome, there was no factor affected the differences of visibility scale scores between TXI-1/TXI-2 and WLI.

CONCLUSIONS

This study demonstrated that TXI-1 and TXI-2 enhanced the visibility scale scores of gastric neoplasms compared with that of WLI. Moreover, newly developed endoscope has the potential to improve visibility compared to conventional endoscope.

TRIAL REGISTRATION

This study was registered with the University Hospital Medical Information Network (UMIN000042429, 16/11/2020).

Knowledge, attitude, and practice of monitoring early gastric cancer after endoscopic submucosal dissection

BACKGROUND

Early gastric cancer (EGC) is typically treated with endoscopic submucosal dissection (ESD). However, recurrence may occur after ESD, requiring surveillance.

AIM

To examine the knowledge, attitude, and practice (KAP) of EGC survivors following ESD regarding gastric cancer recurrence.

METHODS

This cross-sectional study was conducted between June 1, 2022 and October 1, 2022 in Zhejiang, China. A total of 400 EGC survivors who underwent ESD at the Affiliated Jinhua Hospital, Zhejiang University School of Medicine participated in this study. A self-administered questionnaire was developed to assess KAP monitoring gastric cancer after ESD.

RESULTS

The average scores for KAP were 3.34, 23.76, and 5.75 out of 5, 30, and 11, respectively. Pearson correlation analysis revealed positive and significant correlations between knowledge and attitude, knowledge and practice, and attitude and practice (r = 0.405, 0.511, and 0.458, respectively; all P < 0.001). Multivariate logistic regression analysis showed that knowledge, attitude, 13-24 mo since the last ESD (vs ≤ 12 mo since the last ESD), and ≥ 25 mo since the last ESD (vs ≤ 12 mo since the last ESD) were independent predictors of proactive practice (odds ratio = 1.916, 1.253, 3.296, and 5.768, respectively, all P < 0.0001).

CONCLUSION

EGC survivors showed inadequate knowledge, positive attitude, and poor practices in monitoring recurrences after ESD. Adequate knowledge, positive attitude, and a longer time since the last ESD were associated with practice.

Small nonfunctional pancreatic neuroendocrine neoplasms: Time for a step-up treatment approach?

Surgery has been regarded as the only curative treatment for patients with small nonfunctional pancreatic neuroendocrine neoplasms (NF-PNENs) less than 2 cm. Due to the significant adverse event rates of surgery, the European Neuroendocrine Tumor Society issued guidelines favoring surveillance for those patients lacking criteria suggestive of an aggressive disease. Despite the above recommendations, a significant proportion of small NF-PNEN patients still undergo surgery. Recently, several studies have reported the safety and effectiveness of EUS-guided radiofrequency ablation (RFA) for the treatment of small NF-PNENs. The experience with EUS-RFA is, however, limited, but published results indicate a potential role as a minimally invasive alternative treatment for these patients, in particular in those in whom further progression is more probable, before they reach the absolute need for surgery. A step-up approach with EUS-RFA followed by surgery for the failure cases can become a valid option to be validated in clinical studies.

Increasing trend of Helicobacter pylori-uninfected gastric cancer without gastric atrophy

The prevalence of Helicobacter pylori (H. pylori) has decreased during several decades due to improvements in the sanitary environment in Japan. Consequently, a relative increase in the incidence of H. pylori-uninfected gastric cancer is expected. We analyzed the trends in H. pylori-uninfected gastric cancer. Two hundred fifty-eight patients with gastric cancer were retrospectively analyzed. The study was divided into four periods: 2008-2011 (first period), 2012-2014 (second period), 2015-2017 (third period), and 2018-2021 (fourth period). The status of H. pylori infection was divided into four categories: uninfected, successful eradication, spontaneous eradication, and persistent infection. Gastric mucosal atrophy was divided into six grades according to the Kimura-Takemoto classification. The proportion of H. pylori infections significantly changed over the study period (p = 0.007). In particular, the rate of H. pylori-uninfected gastric cancer tended to increase over time (0%, 2.9%, 4.9%, and 13.4% in the first, second, third, and fourth periods, respectively; p = 0.0013). The rate of no atrophy (C-0) in gastric cancer tended to increase over time (0%, 2.9%, 4.9%, and 11.0% in the first, second, third, and fourth periods, respectively; p = 0.0046). In conclusion, the rate of H. pylori-uninfected gastric cancer without gastric atrophy tended to increase over time.

Endoscopic diagnosis of early gastric cancer

Background: Among the types of gastric cancer, the proportion of early gastric cancer has shown a steady increase because the national screening programs have been conducted in Korea. Accordingly, the paradigm shift of the treatment procedure from surgical gastrectomy to endoscopic resection for selected early gastric cancer has accelerated recently. For successful treatment of early gastric cancer, early detection is essential to accurately predict the histological type, depth of invasion, and horizontal margins of the tumor.Current Concepts: The diagnosis of early gastric cancer and selection of treatment procedures comprises the following steps: (1) presence diagnosis, (2) qualitative diagnosis, and (3) quantitative diagnosis. Presently, early gastric cancer diagnosis is based on the endoscopic detection of a demarcated lesion and irregularity of the mucosal surface or color pattern. If a lesion is diagnosed as early gastric cancer, qualitative and quantitative diagnostic processes should be conducted. Qualitative diagnosis predicts the histological type (differentiated vs. undifferentiated), whereas quantitative diagnosis predicts the invasion depth and horizontal margins of the lesion. The diagnostic processes are based on the macroscopic morphology and color of the lesion, while sometimes using chromoendoscopy, image-enhanced endoscopy, and magnifying endoscopy.Discussion and Conclusion: If gastric cancer is detected at an early stage, most cases can be treated only by endoscopic resection. Therefore, endoscopists should have systematic knowledge regarding the findings of early gastric cancer for timely detection and appropriate selection of the treatment procedure.

Endoscopic Classifications of Early Gastric Cancer: A Literature Review

Simple Summary

Throughout the years, endoscopic technologies have advanced to facilitate better assessment of gastric lesions and early detection of gastric cancer. With improvements in conventional white light endoscopy, we have also witnessed the development of newer endoscopic diagnostic modalities, giving rise to several classifications for early gastric cancer. Different endoscopic classifications of early gastric based on several endoscopic diagnostic modalities were included in this review. In addition to this, newer and novel endoscopic classifications that were specifically developed for the stomach for assessing and diagnosing gastric lesions have also been included. Illustrative representations of each classification have also been provided to aid readers in better understanding of these endoscopic classifications of early gastric cancer.

Abstract

Endoscopic technologies have been continuously advancing throughout the years to facilitate improvement in the detection and diagnosis of gastric lesions. With the development of different endoscopic diagnostic modalities for EGC, several classifications have been advocated for the evaluation of gastric lesions, aiming for an early detection and diagnosis. Sufficient knowledge on the appearance of EGC on white light endoscopy is fundamental for early detection and management. On the other hand, those superficial EGC with subtle morphological changes that are challenging to be detected with white light endoscopy may now be clearly defined by means of image-enhanced endoscopy (IEE). By combining magnifying endoscopy and IEE, irregularities in the surface structures can be evaluated and highlighted, leading to improvements in EGC diagnostic accuracy. The main scope of this review article is to offer a closer look at the different classifications of EGC based on several endoscopic diagnostic modalities, as well as to introduce readers to newer and novel classifications, specifically developed for the stomach, for the assessment and diagnosis of gastric lesions.