Metachronous Gastric Cancer Following Curative Endoscopic Resection of Early Gastric Cancer

Impact of endoscopy intervals on metachronous gastric cancer after endoscopic submucosal dissection: Comparison between 1 year and half-a-year

OBJECTIVES

Japanese guidelines recommend posttreatment endoscopy once or twice a year after endoscopic submucosal dissection (ESD) for early gastric cancer. However, the impact of endoscopy intervals on metachronous gastric cancer (MGC) remains unclear, especially the difference between 1-year and half-a-year intervals. We aimed to investigate this difference.

METHODS

This study retrospectively investigated 2429 patients who underwent gastric ESD between May 2001 and June 2019 at our hospital. Patients who developed MGC were classified based on those who underwent the previous endoscopy within at least 7 months (short-interval group) and within 8-13 months (regular-interval group). Propensity score matching (PSM) was used to adjust for possible confounders. The primary outcome was the proportion of MGC beyond curative ESD criteria established in the guidelines.

RESULTS

A total of 216 eligible patients developed MGC. The short- and regular-interval groups included 43 and 173 patients, respectively. Overall, no patients in the short-interval group had MGC beyond curative ESD criteria, while 27 patients in the regular-interval group did. The proportion of MGC beyond curative ESD criteria was significantly lower in the short-interval group than in the regular-interval group before (P = 0.003) and after (P = 0.028) PSM. Although not significant, the short-interval group tended to have a higher stomach preservation rate than the regular-interval group (P = 0.093).

CONCLUSION

Our study indicated a possible benefit of biannual surveillance endoscopy in the early post-ESD period.

Risk assessment of metachronous gastric cancer after endoscopic submucosal dissection based on endoscopic intestinal metaplasia

Background and Aim

The incidence of metachronous gastric cancer (MGC) after endoscopic treatment for early gastric cancer (EGC) is high, but a method of risk assessment for MGC based on endoscopic findings has not been established. In this study, we focused on endoscopic intestinal metaplasia (IM) and investigated the risk for MGC after endoscopic submucosal dissection (ESD) for EGC.

Methods

This retrospective observational study involved patients who underwent curative ESD for EGC from April 2015 to January 2021. We assessed endoscopic IM using the pretreatment endoscopic examination images. The severity of endoscopic IM was classified into four levels: 0 (none), 1 (mild), 2 (moderate), and 3 (severe). Four different gastric areas were evaluated. We divided the patients into a low-score group and a high-score group, and compared the cumulative incidence of MGC.

Results

In total, 156 patients who met the inclusion criteria were followed up for at least 12 months after ESD, and MGC developed in 14 patients during a mean period oof 41.5 months. The endoscopic IM scores in the lesser curvature of the antrum, lesser curvature of the corpus, and greater curvature of the corpus were higher in patients with MGC than in those without MGC. In the corpus, the 5-year cumulative incidence of MGC was significantly higher in the high-score group than in the low-score group (29.8% vs 10.0%, P = 0.004).

Conclusion

The severity of endoscopic corpus IM was associated with MGC. Thus, patients with severe corpus IM at the time of ESD require careful examination and intensive follow-up.

Decision to perform additional surgery after non-curative endoscopic submucosal dissection for gastric cancer based on the risk of lymph node metastasis: a long-term follow-up study

BACKGROUND

Radical surgery after non-curative endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) may be excessive, since only 5-10% of patients have lymph node metastasis (LNM). This study investigated the suitability of the eCura system for determining the need for radical surgery after non-curative ESD.

METHODS

We retrospectively investigated 343 patients who underwent non-curative ESD for EGC from 2006 to 2021 at a tertiary hospital in Korea. These patients were divided into surgery (n = 191) and observation (n = 152) groups based on whether they underwent additional surgery post-ESD. Each group was further classified into low-risk (eCura score 0-1), intermediate-risk (eCura score 2-4) and high-risk (eCura score 5-7). All patients were regularly followed-up at least annually after the initial treatment. The cumulative overall and recurrence-free survival rates were calculated for each category and compared between the surgery and observation groups.

RESULTS

No significant differences in overall survival were found between the surgery and observation groups in low-risk (p = 0.168) and intermediate-risk patients (p = 0.306); however, high-risk patients had better 5-year overall survival rate in the surgery group than in the follow-up group (95.2% vs. 71.4%, p < 0.001). The 5-year recurrence-free survival rate was higher in the surgery group than in the observation group for low-risk (100% vs. 84.3%; p = 0.034), intermediate-risk (96.1% vs. 88.4%; p = 0.081) and high-risk patients (100% vs. 83.3%; p = 0.023).

CONCLUSIONS

Follow-up without additional surgery after non-curative ESD can be a reasonable option for low-risk and even intermediate-risk patients according to the eCura system. However, surgery is warranted for eCura high-risk patients.

Metachronous lesions after gastric endoscopic submucosal dissection: first assessment of the FAMISH prediction score

BACKGROUND

Surveillance after gastric endoscopic submucosal dissection (ESD) is recommended for all patients owing to the persistent risk of metachronous gastric lesions (MGLs). We developed and validated a prediction score to estimate MGL risk after ESD for early neoplastic gastric lesions, to define an individualized and cost-saving approach.

METHODS

Clinical predictors and a risk score were derived from meta-analysis data. A retrospective, single-center, cohort study including patients with ≥ 3 years of standardized surveillance after ESD was conducted for score validation. Predictive accuracy of the score by the area under the receiver operating characteristic curve (AUC) was assessed and cumulative probabilities of MGL were estimated.

RESULTS

The risk score (0-9 points) included six clinical predictors (scored 0-3): positive family history of gastric cancer, older age, male sex, corpus intestinal metaplasia, synchronous gastric lesions, and persistent Helicobacter pylori infection (FAMISH). The study population included 263 patients. The MGL rate was 16 %. The score diagnostic accuracy for predicting MGL at 3 years' follow-up, measured by the AUC, was 0.704 (95 %CI 0.603-0.806). At 3 years and a cutoff < 2, the score achieved maximal sensitivity and negative predictive value; 15 % of patients could be assigned to a low-risk group, in which the progression to MGL was significantly lower than for the high-risk group (P = 0.04).

CONCLUSION

The FAMISH score might be a useful tool to accurately identify patients with low-to-intermediate risk for MGL at 3 years of follow-up who could have surveillance intervals extended to reduce the burden of care.

Helicobacter pylori Eradication Can Reverse Rho GTPase Expression in Gastric Carcinogenesis

Background/Aims

Altered DNA methylation is a key mechanism of epigenetic modification in gastric cancer (GC). This study aimed to evaluate the changes in epigenetic and genetic expression of multiple Rho GTPases in Helicobacter pylori-related gastric carcinogenesis by comparing H. pylori-positive GCs and negative controls.

Methods

The messenger RNA expression and methylation of Rho GTPases (RhoA, Rac1, DOCK180, ELMO1, and CDC42) were evaluated in H. pylori-negative (control) human gastric tissues and H. pylori-positive GCs by using real-time reverse transcription-polymerase chain reaction and the quantitative MethyLight assay, respectively. Changes in expression and methylation levels of the genes were also compared between H. pylori-eradicated and -persistent GCs at 1-year follow-up.

Results

In GCs, the methylation and expression levels of DOCK180 and ELMO1 were higher than in controls, while RhoA and Rac1 had lower levels than controls. CDC42 had the same expression pattern as DOCK180 and ELMO1 without DNA methylation. Although methylation levels of DOCK180 and ELMO1 had no difference between H. pylori-eradicated and -persistent GCs at the index endoscopic resection, those of H. pylori-persistent GCs increased and H. pylori-eradicated GCs decreased for 1 year. The expression levels of DOCK180, ELMO1, and CDC42 in H. pylori-persistent GCs were higher than those in H. pylori-eradicated GCs over 1 year, unlike those of RhoA and Rac1. The methylation levels at index and the degrees of change over time of RhoA and Rac1 had no difference between H. pylori-persistent and -eradicated GCs.

Conclusions

Epigenetic alterations of DOCK180 and ELMO1 are involved in H. pylori-related gastric carcinogenesis. This epigenetic field could be improved by H. pylori eradication.

Variation in the rate of detection of minute and small early gastric cancers at diagnostic endoscopy may reflect the performance of individual endoscopists

OBJECTIVE

The documented variation in gastric cancer (GC) detection among endoscopists has often been dismissed as a coincidental artefact of the low incidence of gastric neoplasms; it is not considered associated with differences in physicians' performance of the esophagogastroduodenoscopy procedure. This study is to confirm whether significant variations among endoscopists in early GC detection suggest the individual performance of the upper endoscopy.

DESIGN

A retrospective observational study at a single centre in Japan assessed the results of 218 early GCs detected during 25 688 routine esophagogastroduodenoscopies by 12 endoscopists. The main outcome was the rate of early GC detection for each endoscopist under the same circumstances. Other measures included the major diameters and locations of the lesions, Helicobacter pylori infection status, and baseline patient characteristics that could affect the prevalence of GC.

RESULTS

The early GC detection rates exhibited wide variation among endoscopists (0.09%-2.87%) despite performing routine esophagogastroduodenoscopies in a population with a similar background. Endoscopists were assigned to a low-detection group (n=6; detection rate: 0.47% (range: 0.09%-0.55%)) and a high-detection group (n=5; detection rate: 0.83% (range: 0.63%-1.12%)), with the single highest detector analysed separately due to his distinct detection rate (2.87%). Endoscopists in the high-detection group had better detection rates for minute (major diameter ≤5 mm) and small (major diameter 6-10 mm) GCs than the low-detection group (0.19%/0.23% vs 0.085%/0.098%). These differences were significant (p<0.01), although there were no significant differences in detection of larger tumours (major diameter ≥11 mm; 0.40% vs 0.28%; p=0.13). The tumour location and H. pylori status were similar in the low-detection group, high-detection group and for the highest detector.

CONCLUSION

Significant variation in the detection of hard-to-find, smaller GCs may reflect individual performance of the examination.

Risk assessment of metachronous gastric cancer development using OLGA and OLGIM systems after endoscopic submucosal dissection for early gastric cancer: a long-term follow-up study

BACKGROUND

Metachronous gastric cancer (MGC) may develop in patients undergoing curative endoscopic submucosal dissection for early gastric cancer. As gastritis and intestinal metaplasia are notable precursors to gastric cancer, we assessed MGC risk using the Operative Link on Gastritis Assessment (OLGA) and Operative Link on Gastric Intestinal Metaplasia assessment (OLGIM) systems.

METHODS

This retrospective cohort study classified the OLGA and OLGIM stages for 916 patients who had undergone endoscopic submucosal dissection for early gastric cancer between 2005 and 2015. MGC development was followed up until 2020 and risk factors were evaluated using the Cox proportional hazards regression analysis.

RESULTS

During a median follow-up of 94 months, MGC developed in 120 subjects. OLGA stages II ~ IV were significantly associated with increased MGC risk (hazard ratio [HR] 1.83, 95% confidence interval [CI] 1.05-3.19; HR 2.31, 95% CI 1.22-4.38; HR 2.36, 95% CI 1.16-4.78) in multivariable analysis, even after adjusting for the well-known positive predictor of Helicobacter pylori eradication. OLGIM stages II ~ IV also showed significant association (HR 2.86, 95% CI 1.29-6.54; HR 2.94, 95% CI 1.34-6.95; HR 3.64, 95% CI 1.60-8.29). 5-year cumulative incidence increased with each stage. Helicobacter pylori-eradicated patients with OLGIM stages 0 ~ II had significantly less MGC than non-eradicated patients (4.5% vs 11.8%, p = 0.022), which was not observed with OLGIM stages III ~ IV.

CONCLUSIONS

High OLGA and OLGIM stages are independent risk factors for metachronous gastric cancer, with the OLGIM staging system being a better predictor. Patients with OLGIM stages 0 ~ II are a subgroup that may benefit more from Helicobacter pylori eradication.

Assigning a different endoscopist for each annual follow-up may contribute to improved gastric cancer detection rates

Background and study aims  Esophagogastroduodenoscopy (EGD) is an effective and important diagnostic tool to detect gastric cancer (GC). Although previous studies show that examiner, patient, and instrumental factors influence the detection of GC, we analyzed whether assigning a different examiner to surveillance EGD would improve the detection of GC compared to assigning the same examiner as in the previous endoscopy. Patients and methods  We retrospectively reviewed patients who underwent two or more consecutive surveillance EGDs at a single center between 2017 and 2019. We identified factors associated with GC detection using multivariable regression analysis and propensity-score matching. Results  Among 7794 patients, 99 GC lesions in 93 patients were detected by surveillance EGD (detection rate; 1.2 %), with a mean surveillance interval of 11.2 months. Among the detected 99 lesions, 87 (87.9 %) were curatively treated with endoscopy. There were no differences in the clinicopathologic characteristics of GC detected by the same or different endoscopists. GC detection in the group examined by different endoscopists was more statistically significant than in the group examined by the same endoscopist, even after propensity-score matching (1.6 % and 0.7 %; P  < 0.05). Endoscopic experience and other factors were not statistically significant between the two groups. Conclusions  In surveillance EGD, having a different endoscopist for each exam may improve GC detection rates, regardless of the endoscopist's experience.

Statistical proof of Helicobacter pylori eradication in preventing metachronous gastric cancer after endoscopic resection in an East Asian population

We conducted a comprehensive literature review and meta-analysis study on the efficacy of Helicobacter pylori (H. pylori) eradication in preventing metachronous gastric cancer after endoscopic resection among an East Asian population. Our results showed that the eradication of this pathogen significantly reduced the risk of susceptibility to metachronous gastric cancer in these patients. However, based on the available evidence, several factors such as increasing age, severe atrophy in the corpus and antrum, and intestinal metaplasia all may increase the risk of metachronous gastric cancer in H. pylori eradicated patients.

Assessment of Outcomes From 1-Year Surveillance After Detection of Early Gastric Cancer Among Patients at High Risk in Japan

IMPORTANCE

Single endoscopic examination often misses early gastric cancer (GC), even when both high-definition white light imaging and narrow-band imaging are used. It is unknown whether new GC can be detected approximately 1 year after intensive index endoscopic examination.

OBJECTIVE

To examine whether new GC can be detected approximately 1 year after intensive index endoscopic examination using both white light and narrow-band imaging.

DESIGN, SETTING, AND PARTICIPANTS

This case-control study was a preplanned secondary analysis of a randomized clinical trial involving 4523 patients with a high risk of GC who were enrolled between October 1, 2014, and September 22, 2017. Data were analyzed from December 26, 2019, to April 21, 2021. Participants in the clinical trial received index endoscopy to detect early GC via 2 examinations of the entire stomach using white light and narrow-band imaging. The duration of follow-up was 15 months. The secondary analysis included 107 patients with newly detected GC (case group) and 107 matched patients without newly detected GC (control group) within 15 months after index endoscopy.

INTERVENTIONS

Surveillance endoscopy was scheduled between 9 and 15 months after index endoscopy. If new lesions suspected of being early GC were detected during surveillance endoscopy, biopsies were obtained to confirm the presence of cancer.

MAIN OUTCOMES AND MEASURES

The primary end point was the rate of new GC detected within 15 months after index endoscopy. The main secondary end point was identification of risk factors associated with new GC detected within 15 months after index endoscopy.

RESULTS

Among 4523 patients (mean [SD] age, 70.6 [7.5] years; 3527 men [78.0%]; all of Japanese ethnicity) enrolled in the clinical trial, 4472 received index endoscopy; the rate of early GC detected on index endoscopy was 3.0% (133 patients). Surveillance endoscopy was performed in 4146 of 4472 patients (92.7%) who received an index endoscopy; the rate of new GC detected within 15 months after index endoscopy was 2.6% (107 patients). Among 133 patients for whom early GC was detected during index endoscopy, 110 patients (82.7%) received surveillance endoscopy within 15 months after index endoscopy; the rate of newly detected GC was 10.9% (12 patients). For the secondary analysis of risk factors associated with newly detected GC, characteristics were well balanced between the 107 patients included in the case group vs the 107 patients included in the matched control group (mean [SD] age, 71.7 [7.2] years vs 71.8 [7.0] years; 94 men [87.9%] in each group; 82 patients [76.6%] vs 87 patients [81.3%] with a history of gastric neoplasm). Multivariate analysis revealed that the presence of open-type atrophic gastritis (odds ratio, 6.00; 95% CI, 2.25-16.01; P < .001) and early GC detection by index endoscopy (odds ratio, 4.67; 95% CI, 1.08-20.21; P = .04) were independent risk factors associated with new GC detection.

CONCLUSIONS AND RELEVANCE

In this study, the rate of new GC detected by surveillance endoscopy approximately 1 year after index endoscopy was similar to that of early GC detected by index endoscopy. These findings suggest that 1-year surveillance is warranted for patients at high risk of GC.

Therapeutic approach to non-curative resection after endoscopic treatment in early gastric cancer

Background: Endoscopic resection is indicated for early or superficial gastrointestinal neoplasms with a negligible risk of lymph node metastasis. This procedure could preserve the organ while allowing en bloc resection of tumors, irrespective of the size and location of the lesion. Histological evaluation of the resected specimen determines whether curative resection, which implies a favorable long-term outcome, was achieved. If the resected specimen reveals non-curative, additional treatment is necessary as it is strongly associated with recurrence.Current Concepts: Surgical resection is recommended after non-curative resection of gastrointestinal neoplasms. However, rather than surgical resection, additional endoscopic treatment can be recommended if non-curative resection is solely because of the positive involvement at the horizontal resection margin without any other findings compatible with the non-curative resection criteria.Discussion and Conclusion: Adopting precise indications of endoscopic resection is important to reduce the risk of non-curative resection. If curative resection is not achieved after endoscopic resection, additional treatment should be considered to prevent local recurrence as well as lymph node metastasis.

Second gastric cancer after curative endoscopic resection of differentiated-type early gastric cancer: post-hoc analysis of a single-arm confirmatory trial

BACKGROUND AND AIMS

Endoscopic resection (ER) for early gastric cancer (EGC) can preserve the stomach; however, the remaining stomach can develop second gastric cancer. Few reports have prospectively investigated the incidence and treatment outcomes of second gastric cancer.

METHODS

This post-hoc analysis used the dataset of the single-arm confirmatory trial, JCOG0607. The key inclusion criteria for JCOG0607 were solitary differentiated-type EGC and no previous gastrectomy or endoscopic treatment for EGC. Three hundred seventeen patients who underwent curative ER were included in this study. Surveillance endoscopy was performed 1 to 3 months after the initial ER and subsequently annually for at least 5 years. A lesion detected ≤1 year and >1 year after the initial ER was defined as overlooked gastric cancer (OGC) and metachronous gastric cancer (MGC), respectively.

RESULTS

During a median follow-up period of 6.0 years (interquartile range, 5.1-7.0), 30 OGCs and 61 MGCs were detected in 24 and 48 patients, respectively. The cumulative incidence of OGC at 1 year and MGC at 5 years was 7.6% and 12.7%, respectively. ER and gastrectomy were performed in 85 lesions and 6 lesions, respectively. Pathologic evaluation showed 78 mucosal cancers, 12 submucosal cancers, and 1 advanced cancer. Eventually, 28 OGCs and 52 MGCs fulfilled the pathologic criteria for curative ER.

CONCLUSIONS

Our study was the first to reveal the actual incidence of second gastric cancer after curative ER for differentiated-type gastric cancer. Most lesions could be treated with ER. Continuous endoscopic surveillance after curative ER is important to detect second gastric cancer.

Characteristics of metachronous gastric neoplasms after curative endoscopic submucosal dissection for early gastric neoplasms

BACKGROUND

With the wide application of endoscopic submucosal dissection (ESD) for early gastric neoplasms, metachronous gastric neoplasms (MGN) have gradually become a concern. This study aimed to analyze the characteristics of MGN and evaluate the treatment and follow-up outcomes of MGN patients.

METHODS

A total of 814 patients were retrospectively enrolled. All these patients were treated by ESD for early gastric cancer or gastric dysplasia between November 2006 and September 2019 at The First Medical Center of Chinese People's Liberation Army General Hospital. The risk factors for MGN were analyzed using Cox hazard proportional model. Moreover, the cumulative incidence, the correlation of initial lesions and MGN lesions, and the treatment and follow-up outcomes of MGN patients were analyzed.

RESULTS

A total of 4.5% (37/814) of patients had MGN after curative ESD. The 3-, 5-, and 7-year cumulative incidences of MGN were 3.5%, 5.1%, and 6.9%, respectively, and ultimately reaching a plateau of 11.3% at 99 months after ESD. There was no significant correlation between initial lesions and MGN lesions in terms of gross type (P = 0.178), location (long axis: P = 0.470; short axis: P = 0.125), and histological type (P = 0.832). Cox multivariable analysis found that initial multiplicity was the only independent risk factor of MGN (hazard ratio: 4.3, 95% confidence interval: 2.0-9.4, P < 0.001). Seventy-three percent of patients with MGN were treated by endoscopic resection. During follow-up, two patients with MGN died of gastric cancer with lymph node metastasis. The disease-specific survival rate was significantly lower in patients with MGN than that in patients without MGN (94.6% vs. 99.6%, P = 0.006).

CONCLUSIONS

The MGN rate gradually increased with follow-up time within 99 months after curative gastric ESD. Thus, regular and long-term surveillance endoscopy may be helpful, especially for patients with initial multiple neoplasms.

Molecular risk markers related to local tumor recurrence at histological margin-free endoscopically resected early gastric cancers: A pilot study

Local recurrences in early gastric cancers (EGCs) after complete endoscopic submucosal dissection (ESD) remain problematic. Here, we investigated the spatially sequential molecular changes in various cancer-related proteins along the axis of the histologically clear but recurrent resection margins (TRM) to determine the appropriate tumor-free margin distance and potential molecular risk markers related to local recurrence. Five eligible patients with recurrent EGCs after complete ESD were selected from 548 EGC patients. The specimens, including recurrent resection margin axis, were divided into 5 zones. Digital spatial profiling assay was performed to quantify the expression level of 31 cancer-related proteins along each zone. p-Chk1 level was significantly reduced in TRM zone than non-recurrent resection margin. The expression of p44/42 ERK and p-Chk1 were significantly decreased along the lateral axis of the recurrent resection margin, with no significance toward the normal zone, which may suggest that p44/42 ERK and p-Chk1 may be involved in the recurrent side compared to non-recurrent margin. Although we could not evaluate more than 5.5 mm, the significant linear decreases in p44/42 ERK and p-Chk1 were maintained until at least 5.5 mm from the tumor zone in the TRM direction. We estimated the possible margin distance using scatterplots and linear regression analyses, which also showed the estimated distance more than 5.5 mm. In conclusion, the p-Chk1 and p44/42 ERK may be potential candidates of molecular risk markers that may be related to the local recurrence after complete ESD, and a tumor-free distance of 5.5 mm is not enough for safety margin.

Incidence of metachronous cancer after endoscopic submucosal dissection: a comparison between undifferentiated-type and differentiated-type early gastric cancer

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) has become an important and minimally invasive treatment for early gastric cancer (EGC) with a negligible risk of metastasis not only for differentiated-type (D-type) cancer but also for undifferentiated-type (UD-type) cancer. We aimed to investigate the incidence and characteristics of metachronous cancer after ESD for UD-type cancer, which has not yet been elucidated.

METHODS

In total, 175 patients who underwent ESD for UD-type EGC were enrolled. For comparison, 350 patients who underwent ESD for D-type EGC during the same period were randomly selected. These patients underwent a follow-up EGD annually. The median observation period was 6.0 years and 5.4 years, respectively.

RESULTS

The annual incidence of metachronous cancer after ESD for UD-type and D-type cancer was .9% and 5.3%, respectively. Among the patients who underwent ESD for UD-type cancer, 30.9% of patients were uninfected with Helicobacter pylori, whereas all patients who underwent ESD for D-type cancer were infected with H pylori. All patients who developed metachronous cancer were infected with H pylori. UD-type metachronous cancer developed more frequently in patients after ESD for UD-type cancer than after ESD for D-type cancer, and the curative resection rate of ESD was significantly lower in these cases.

CONCLUSIONS

Metachronous cancers developed only in H pylori-infected patients in this cohort. Although metachronous cancer incidence was significantly less frequent in patients after ESD for UD-type cancer, the curative resection rate of ESD was significantly lower. Routine surveillance should be conducted more carefully after ESD for UD-type cancer, especially in H pylori-infected patients.

Artificial intelligence in gastric cancer: a translational narrative review

Increasing clinical contributions and novel techniques have been made by artificial intelligence (AI) during the last decade. The role of AI is increasingly recognized in cancer research and clinical application. Cancers like gastric cancer, or stomach cancer, are ideal testing grounds to see if early undertakings of applying AI to medicine can yield valuable results. There are numerous concepts derived from AI, including machine learning (ML) and deep learning (DL). ML is defined as the ability to learn data features without being explicitly programmed. It arises at the intersection of data science and computer science and aims at the efficiency of computing algorithms. In cancer research, ML has been increasingly used in predictive prognostic models. DL is defined as a subset of ML targeting multilayer computation processes. DL is less dependent on the understanding of data features than ML. Therefore, the algorithms of DL are much more difficult to interpret than ML, even potentially impossible. This review discussed the role of AI in the diagnostic, therapeutic and prognostic advances of gastric cancer. Models like convolutional neural networks (CNNs) or artificial neural networks (ANNs) achieved significant praise in their application. There is much more to be fully covered across the clinical administration of gastric cancer. Despite growing efforts, adapting AI to improving diagnoses for gastric cancer is a worthwhile venture. The information yield can revolutionize how we approach gastric cancer problems. Though integration might be slow and labored, it can be given the ability to enhance diagnosing through visual modalities and augment treatment strategies. It can grow to become an invaluable tool for physicians. AI not only benefits diagnostic and therapeutic outcomes, but also reshapes perspectives over future medical trajectory.

Clinical Outcomes of Metachronous Gastric Cancer after Endoscopic Resection for Early Gastric Cancer

Background/Aims

Patients treated with endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) are at risk of developing metachronous gastric cancer (MGC). The aim of this study was to evaluate the clinical outcomes of MGC after ESD for EGC between the re-ESD and surgery groups.

Methods

In total, data from 1,510 patients who underwent ESD for EGC from January 2005 to May 2014 were retrospectively reviewed, and data from 112 patients with MGC were analyzed according to the type of treatment, namely, re-ESD and surgery. The clinicopathological factors affecting the subsequent treatment and outcomes of MGC were evaluated.

Results

The median duration to the development of MGC was 47 months. In multivariate analysis, lower body mass index (BMI) (p=0.037) and multiplicity (p=0.014) of index cases were significantly associated with subsequent surgery for MGC. In cases of MGC, a diffuse or mixed-type Lauren classification (p=0.009), the depth of tumor mucosal invasion (p=0.001), and an upper stomach location (p=0.049) were associated with surgery. Overall survival was significantly shorter in the surgery group than in the re-ESD group after treatment for MGC (log-rank test, p=0.01).

Conclusions

Lower BMI and multiplicity of index cancers were significantly associated with the surgical resection of MGC. Close follow-up is needed to minimize additional treatment for cases at high risk of advanced MGC after ESD for EGC.

Somatic alterations and mutational burden are potential predictive factors for metachronous development of early gastric cancer

The risk of developing metachronous gastric cancer (MGC) following curative endoscopic submucosal dissection (ESD) of early gastric cancer (EGC) remains even after eradicating Helicobacter pylori (HP) successfully. We screened initial EGC and adjacent non-cancerous mucosa ESD-resected specimens for somatic variants of 409 cancer-related genes, assessing their mutational burden (MB) to predict molecular markers for metachronous post-ESD development. We compared variants between ten patients diagnosed with MGC more than 3 years after ESD and ten age-matched patients who did not have MGC developments after successful HP eradication. We found no significant background differences between the two groups. In adjacent non-cancerous mucosa, the MB tended to be higher in the patients with metachronous developments than in the others. Somatic genomic alterations of RECQL4, JAK3, ARID1A, and MAGI1 genes were significantly associated with MGC development. The criteria including both the MB and their variants, which had potential significant values for predicting MGC. In conclusion, combined of assessing specific somatic variants and MB may be useful for predicting MGC development. This study included a limited number of subjects; however, our novel findings may encourage further exploration of the significance of the molecular features of EGC that predict MGC development, thereby promoting focused follow-up strategies and helping elucidate the mechanisms.

Gastric cancer screening in low incidence populations: Position statement of AEG, SEED and SEAP

This positioning document, sponsored by the Asociación Española de Gastroenterología, the Sociedad Española de Endoscopia Digestiva and the Sociedad Española de Anatomía Patológica, aims to establish recommendations for the screening of gastric cancer (GC) in low incidence populations, such as the Spanish. To establish the quality of the evidence and the levels of recommendation, we used the methodology based on the GRADE system (Grading of Recommendations Assessment, Development and Evaluation). We obtained a consensus among experts using a Delphi method. The document evaluates screening in the general population, individuals with relatives with GC and subjects with GC precursor lesions (GCPL). The goal of the interventions should be to reduce GC related mortality. We recommend the use of the OLGIM classification and determine the intestinal metaplasia (IM) subtype in the evaluation of GCPL. We do not recommend to establish endoscopic mass screening for GC or Helicobacter pylori. However, the document strongly recommends to treat H.pylori if the infection is detected, and the investigation and treatment in individuals with a family history of GC or with GCPL. Instead, we recommend against the use of serological tests to detect GCPL. Endoscopic screening is suggested only in individuals that meet familial GC criteria. As for individuals with GCPL, endoscopic surveillance is only suggested in extensive IM associated with additional risk factors (incomplete IM and/or a family history of GC), after resection of dysplastic lesions or in patients with dysplasia without visible lesion after a high quality gastroscopy with chromoendoscopy.

Gastric cancer prevention strategies: A global perspective

Gastric cancer (GC) is the fifth most common cancer worldwide, and mortality rates are still high. Primary preventive strategies, aimed to reduce risk factors and promote protective ones, will lead to a decrease in GC incidence. Helicobacter pylori infection is a well-established carcinogen for GC, and its eradication is recommended as the best strategy for the primary prevention. However, the role of other factors such as lifestyle, diet, and drug use is still under debate in GC carcinogenesis. Unfortunately, most patients with GC are diagnosed at late stages when treatment is often ineffective. Neoplastic transformation of the gastric mucosa is a multistep process, and appropriate diagnosis and management of preneoplastic conditions can reduce GC-related mortality. Several screening strategies in relation to GC incidence have been proposed in order to detect neoplastic lesions at early stages. The efficacy of screening strategies in reducing GC mortality needs to be confirmed. This review provides an overview of current international guidelines and recent literature on primary and secondary prevention strategies for GC.

Impact of the timing of Helicobacter pylori eradication on the risk of development of metachronous lesions after treatment of early gastric cancer: a population-based cohort study

BACKGROUND AND AIMS

Helicobacter pylori eradication can reduce the risk of metachronous lesions after the treatment of early gastric cancer. We aimed to analyze the impact of the timing of H pylori eradication on metachronous recurrence.

METHODS

Data of patients who underwent endoscopic resection or partial gastrectomy for early stage gastric cancer and received H pylori eradication therapy were obtained from the Korean National Health Insurance Service database. Patients were classified into 3 groups according to the timing of the prescription for H pylori eradication: preresection; within 1 year postresection; and >1 year postresection.

RESULTS

Among 19,767 patients, 7452 and 12,315 underwent endoscopic resection and surgery, respectively. The 5-year cumulative incidence of metachronous lesions after endoscopic resection was 14.0% in the preresection group, 12.3% in the within 1 year postresection group, and 16.9% in the >1 year postresection group. Surgery was performed in 1.2% of the preresection group, 1.3% of the within 1 year postresection group, and 2.9% of the >1 year postresection group. The within 1 year postresection group had a lower risk of development of metachronous lesions than the >1 year postresection group (hazard ratio [95% confidence interval]: after endoscopic resection, 0.79 [0.65-0.95]; after surgery, 0.39 [0.28-0.53]). The risk of development of metachronous lesions did not differ between the preresection and within 1 year postresection groups.

CONCLUSION

Prescription of H pylori eradication therapy within 1 year after gastric cancer treatment reduces the risk of development of metachronous gastric neoplasms compared with a late prescription of eradication therapy in patients undergoing endoscopic resection and those undergoing surgery.

Long-term follow up of serum pepsinogens in patients with gastric cancer or dysplasia after Helicobacter pylori eradication

BACKGROUND AND AIM

Few studies have evaluated the change in serum pepsinogen (sPG) levels after the eradication of Helicobacter pylori. The aim of this study was to evaluate the effect of H. pylori eradication on sPG levels in patients with gastric cancer/dysplasia in comparison to a control group.

METHODS

We prospectively enrolled 368 patients with gastric cancer/dysplasia and 610 control subjects. H. pylori status and sPG levels were measured before and after eradication. The follow-up time points were classified as < 12, 12-23, 24-35, and ≥ 36 months.

RESULTS

In 179 H. pylori-eradicated patients with gastric cancer/dysplasia and 168 control group subjects, sPG I significantly decreased, and the sPG I/II ratio significantly increased after eradication compared to baseline, and this improvement in sPG values was maintained during all follow-up time points. Significant differences in sPG I and the sPG I/II ratio were observed between the gastric cancer/dysplasia group and the control group < 24 months after eradication. However, these differences in sPG values disappeared after ≥ 24 months of follow up. Moreover, significant differences in the intestinal metaplasia grade were observed between these two groups before eradication until < 24 months after eradication. However, these differences in the intestinal metaplasia grade disappeared after ≥ 24 months of follow up in the corpus.

CONCLUSION

The sPG values and intestinal metaplasia grade (corpus) in the gastric cancer/dysplasia group became similar to those in the control group at long-term follow up after H. pylori eradication. It might be related with the reduction of metachronous gastric neoplasm.

Multifocal early gastric cancer in a patient with atrophic gastritis and pernicious anemia

INTRODUCTION

Pernicious anemia (PA) caused by vitamin B12 deficiency is associated with Autoimmune Metaplastic Atrophic Gastritis (AMAG). Patients with AMAG have threefold risk of the development of gastric cancer.

PRESENTATION OF CASE

We describe a case of a 66 year old man with a history of PA and atrophic antral-corpus gastritis. After endoscopic and chromoendoscopic evaluation the patient was treated with subtotal gastrectomy plus D2 lymphadenectomy. The tumor was diagnosed as Stage Ia; pT1a pN0 pM0 G2 with multiple foci of high grade dysplasia and intramucosal adenocarcinoma.

DISCUSSION

Multifocal Early Gastric Cancer can be a problem for minimally invasive treatment such as endoscopic excision. Surgical management where it is not possible Endoscopic Mucosal Resection or Submucosal Resection (EMR/ESD) should include D1 or more type of lymphadenectomy because of the risk of nodes metastases. The chromoendoscopic evaluation may be helpful in the preoperative work-up and during the follow-up period.

CONCLUSION

Multidisciplinary approach is very important to reduce the under-treatment risk in multifocal early gastric cancer. Further studies will be needed to evaluate the safety of Subtotal vs Total Gastrectomy in this kind of disease.

Chemoprevention of gastric cancer development after Helicobacter pylori eradication therapy in an East Asian population: Meta-analysis

BACKGROUND

Helicobacter pylori (H. pylori) infection is a risk factor for gastric cancer (GC), especially in East Asian populations. Most East Asian populations infected with H. pylori are at higher risk for GC than H. pylori-positive European and United States populations. H. pylori eradication therapy reduces gastric cancer risk in patients after endoscopic and operative resection for GC, as well as in non-GC patients with atrophic gastritis.

AIM

To clarify the chemopreventive effects of H. pylori eradication therapy in an East Asian population with a high incidence of GC.

METHODS

PubMed and the Cochrane library were searched for randomized control trials (RCTs) and cohort studies published in English up to March 2019. Subgroup analyses were conducted with regard to study designs (i.e., RCTs or cohort studies), country where the study was conducted (i.e., Japan, China, and South Korea), and observation periods (i.e., ≤ 5 years and > 5 years). The heterogeneity and publication bias were also measured.

RESULTS

For non-GC patients with atrophic gastritis and patients after resection for GC, 4 and 4 RCTs and 12 and 18 cohort studies were included, respectively. In RCTs, the median incidence of GC for the untreated control groups and the treatment groups was 272.7 (180.4–322.4) and 162.3 (72.5–588.2) per 100000 person-years in non-GC cases with atrophic gastritis and 1790.7 (406.5–2941.2) and 1126.2 (678.7–1223.1) per 100000 person-years in cases of after resection for GC. Compared with non-treated H. pylori-positive controls, the eradication groups had a significantly reduced risk of GC, with a relative risk of 0.67 [95% confidence interval (CI): 0.47–0.96] for non-GC patients with atrophic gastritis and 0.51 (0.36–0.73) for patients after resection for GC in the RCTs, and 0.39 (0.30–0.51) for patients with gastritis and 0.54 (0.44–0.67) for patients after resection in cohort studies.

CONCLUSION

In the East Asian population with a high risk of GC, H. pylori eradication effectively reduced the risk of GC, irrespective of past history of previous cancer.

The Mexican consensus on the detection and treatment of early gastric cancer

Gastric cancer is one of the most frequent neoplasias in the digestive tract and is the result of premalignant lesion progression in the majority of cases. Opportune detection of those lesions is relevant, given that timely treatment offers the possibility of cure. There is no consensus in Mexico on the early detection of gastric cancer, and therefore, the Asociación Mexicana de Gastroenterología brought together a group of experts and produced the "Mexican consensus on the detection and treatment of early gastric cancer" to establish useful recommendations for the medical community. The Delphi methodology was employed, and 38 recommendations related to early gastric cancer were formulated. The consensus defines early gastric cancer as that which at diagnosis is limited to the mucosa and submucosa, irrespective of lymph node metástasis. In Mexico, as in other parts of the world, factors associated with early gastric cancer include Helicobacter pylori infection, a family history of the disease, smoking, and diet. Chromoendoscopy, magnification endoscopy, and equipment-based image-enhanced endoscopy are recommended for making the diagnosis, and accurate histopathologic diagnosis is invaluable for making therapeutic decisions. The endoscopic treatment of early gastric cancer, whether dissection or resection of the mucosa, should be preferred to surgical management, when similar oncologic cure results can be obtained. Endoscopic surveillance should be individualized.

Helicobacter pylori Infection following Endoscopic Resection of Early Gastric Cancer

The role of Helicobacter pylori (H. pylori) infection in patients following endoscopic resection of early gastric cancer (EGC) remains unclear. This article presents a review of literature published in the past 15 years. H. pylori-mediated persistent methylation levels are associated with the development of metachronous gastric cancer. The methylation of certain specific genes can be used to identify patients with a high risk of metachronous gastric cancer even after H. pylori eradication. H. pylori eradication after endoscopic resection should be performed as early as possible for eradication success and prevention of metachronous precancerous lesions. Although whether the eradication of H. pylori could prevent the development of metachronous cancer after endoscopic resection is controversial, several meta-analyses concluded that H. pylori eradication could reduce the incidence of metachronous gastric cancer significantly. In addition, H. pylori eradication in gastric cancer survivors after endoscopic resection could reduce healthcare cost and save lives in a cost-effective way. Taken together, H. pylori eradication after endoscopic resection of EGC is recommended as prevention for metachronous precancerous lesions and metachronous gastric cancer.

Common Locations of Gastric Cancer: Review of Research from the Endoscopic Submucosal Dissection Era

Detection of early-stage gastric cancer improves the prognosis of patients. Endoscopic submucosal dissection (ESD) is a curative and stomach-preserving treatment for early gastric cancer (EGC) associated with a low risk of lymph node metastasis. However, several studies have reported missed diagnosis of gastric cancer. Therefore, endoscopists are required to learn accurate diagnostic skills to eliminate endoscopic blind spots. A systematic screening protocol to map the entire stomach without blind spots reduces the risk of missed lesions. Knowledge of the features of EGC or dysplasia is essential to identify suspicious lesion. Information of the common sites of occurrence of EGC can also enable a detailed endoscopic examination to improve detection rates. Previous reports investigating the location of gastric cancers resected by ESD or surgery showed that the antrum and lesser curvature of stomach were predominantly affected. Helicobacter pylori-induced atrophic changes advance from the antrum to the corpus along the lesser curvature, predominantly affecting these areas. Gastric cancers in the antrum and the lower corpus are also commonly missed during screening examination. Therefore, a careful examination of the lower third stomach is warranted to avoid missing synchronous and metachronous gastric lesions. Knowledge of the location of EGC enables accurate endoscopic examination and detection of EGC in early stage.

Clinicopathologic Characteristics of Patients with Gastric Superficial Neoplasia and Risk Factors for Multiple Lesions after Endoscopic Submucosal Dissection in a Western Country

Background

Endoscopic submucosal dissection (ESD) is a treatment for early gastric neoplasms that preserves the stomach. However, the risk of multiple lesions persists.

Objectives

To assess clinicopathologic characteristics of patients with early gastric neoplasms in a Western country and evaluate risk factors for multiple gastric lesions, synchronous, or metachronous.

Methods

A retrospective cohort of 230 consecutive patients who underwent ESD for primary neoplasms from 2012 to 2017 (median follow-up: 33 months) was assessed to determine the clinicopathologic characteristics and risk factors for multiple lesions.

Results

The mean age was 68 years, and 53.9% were male. Current/former smoking status was present in 40.4%, and 29.5% had family history of gastric cancer. A third of the patients had only focal gastric atrophy/metaplasia (operative link on gastritis assessment/operative link on gastric intestinal metaplasia assessment [OLGA/OLGIM] I/II; endoscopic grading of gastric intestinal metaplasia [EGGIM] 1-4). Synchronous and me-tachronous lesions occurred in 14.3 and 8.6% of patients, respectively. There was a trend for higher risk of multiple lesions in smokers and patients with extensive metaplasia (EGGIM >4), but only older age was an independent risk factor (OR 3.30; 95% CI 1.05-10.34). Age >60 years (OR 10.10, 95% CI 1.40-88.04), current/former smoking status (OR 3.64, 95% CI 1.07-12.40), and OLGIM III/IV (OR 3.07, 95% CI 1.01-9.36) were independent risk factors for synchronous lesions. No risk factors for metachronous lesions were found.

Conclusions

Surveillance limited to patients with advanced stages of gastritis may miss some primary superficial neoplasms. Although older age increases the risk of multiple lesions, no risk factors were found for metachronous lesions. Therefore, endoscopic surveillance after ESD should be done equally in all patients.

Helicobacter pylori status and risks of metachronous recurrence after endoscopic resection of early gastric cancer: a systematic review and meta-analysis

The impact of different Helicobacter pylori (H. pylori) status (H. pylori negative, H. pylori eradication and H. pylori persistence) on the development of metachronous gastric lesions after endoscopic resection of early gastric cancer is not well defined. Thus, a systematic review and meta-analysis was performed to investigate this relationship. Two authors independently searched the electronic databases (Pubmed, Embase, the Cochrane Library and Web of Science) through March 2018, without language restriction. Pooled risk ratio for metachronous gastric lesions with regard to H. pylori status was calculated using fixed- or random-effects models, and heterogeneity and publication bias were also measured. 20 eligible studies were finally identified in systematic review, and 17 out of 20 studies were further included in meta-analysis. H. pylori eradication was associated with overall 50% lower odds of metachronous events (RR = 0.50; 95 % CI 0.41-0.61). Pooled risk ratios for metachronous gastric neoplasm were 0.85 (95 % CI 0.43-1.68) between H. pylori-eradicated and -negative patients, and 0.63 (95 % CI 0.35-1.12) between H. pylori-negative and -persistent patients, respectively. In conclusion, based on the best available evidence, eradication of H. pylori can provide protection against secondary gastric neoplasm, and this quantitative benefit seemed greater than among asymptomatic individuals. Metachronous risk seems comparable between H. pylori-eradicated and -negative population, or between H. pylori-negative and -persistent patients.

Linked Color Imaging and Blue Laser Imaging for Upper Gastrointestinal Screening

White light imaging (WLI) may not reveal early upper gastrointestinal cancers. Linked color imaging (LCI) produces bright images in the distant view and is performed for the same screening indications as WLI. LCI and blue laser imaging (BLI) provide excellent visibility of gastric cancers in high color contrast with respect to the surrounding tissue. The characteristic purple and green color of metaplasias on LCI and BLI, respectively, serve to increase the contrast while visualizing gastric cancers regardless of a history of Helicobacter pylori eradication. LCI facilitates color-based recognition of early gastric cancers of all morphological types, including flat lesions or those in an H. pylori-negative normal background mucosa as well as the diagnosis of inflamed mucosae including erosions. LCI reveals changes in mucosal color before the appearance of morphological changes in various gastric lesions. BLI is superior to LCI in the detection of early esophageal cancers and abnormal findings of microstructure and microvasculature in close-up views of upper gastrointestinal cancers. Excellent images can also be obtained with transnasal endoscopy. Using a combination of these modalities allows one to obtain images useful for establishing a diagnosis. It is important to observe esophageal cancers (brown) using BLI and gastric cancers (orange) surrounded by intestinal metaplasia (purple) and duodenal cancers (orange) by LCI.