Risk stratification for synchronous/metachronous recurrence after endoscopic submucosal dissection for Barrett's esophageal adenocarcinoma using the length of Barrett's esophagus

BACKGROUND

In Japan, the standard management of Barrett's esophageal adenocarcinoma after endoscopic submucosal dissection involves follow-up; however, multifocal synchronous/metachronous lesions are sometimes observed after endoscopic submucosal dissection. Risk stratification of multifocal cancer facilitates appropriate treatment, including eradication of Barrett's esophagus in high-risk cases; however, no effective risk stratification methods have been established. Thus, we identified the risk factors for multifocal cancer and explored risk-stratified treatment strategies for residual Barrett's esophagus.

METHODS

We retrospectively reviewed the data of 97 consecutive patients with superficial Barrett's esophageal adenocarcinomas who underwent curative resection with endoscopic submucosal dissection. Multifocal cancer was defined by the presence of synchronous/metachronous lesions during follow-up. We used Cox regression analysis to identify the risk factors for multifocal cancer and subsequently analyzed differences in cumulative incidences.

RESULTS

The cumulative incidences of multifocal cancer at 1, 3, and 5 years were 4.4%, 8.6%, and 10.7%, respectively. Significant risk factors for multifocal cancer were increased circumferential and maximal lengths of Barrett's esophagus. The cumulative incidences of multifocal cancer at 3 years were lower for patients with circumferential length < 4 cm and maximal length < 5 cm (2.9% and 1.2%, respectively) than for patients with circumferential length ≥ 4 cm and maximal length ≥ 5 cm (51.5% and 49.1%, respectively).

CONCLUSIONS

Risk stratification of multifocal cancer using length of Barrett's esophagus was effective. Further multicenter prospective studies are needed to substantiate our findings.

Effect of Helicobacter pylori eradication evaluated using magnifying endoscopy with narrow-band imaging in mixed-type early gastric Cancer

BACKGROUND

The effect of Helicobacter pylori (H.pylori) eradication therapy on mixed-histological-type gastric cancer remains unclear. This study aimed to clarify the effect of H. pylori eradication therapy on mixed-histological-type early gastric cancer using endoscopic and histological findings.

METHODS

This single-center, retrospective study included patients with mixed-histological-type gastric cancer who underwent endoscopic submucosal dissection at the Cancer Institute Hospital. We compared detailed magnifying endoscopy with narrow-band imaging findings between eradicated and non-eradicated groups of patients with differentiated-type- and undifferentiated-type-predominant cancers. Subsequently, we performed histological evaluations of the non-cancerous epithelium covering differentiated-type components.

RESULTS

A total of 124 patients with mixed-type early gastric cancer were enrolled (eradicated group: 62 differentiated-type-predominant cancer patients and 8 undifferentiated-type-predominant cancer patients; non-eradication group: 40 differentiated-type-predominant cancer patients and 14 undifferentiated-type-predominant cancer patients). Regarding differentiated-type-predominant cancer, differentiated-type findings were detected in all patients in eradicated and non-eradicated groups. The difference in the detection rate of undifferentiated-type findings between both groups was not significant in differentiated-type-predominant cancer patients. In differentiated-type-predominant cancers, the percentage of non-cancerous epithelium covering differentiated-type components was higher in the eradicated group than in the non-eradicated group (median: 60% vs. 40%, p < 0.001).

CONCLUSIONS

Although the pathological findings of differentiated-type-predominant cancer were affected by H. pylori eradication, eradication did not affect the diagnosis of differentiated-type-predominant early gastric cancer using magnifying endoscopy with narrow-band imaging. ME-NBI is useful for the early detection of D-MIX EGCs and diagnosis of histological types during endoscopy, regardless of whether H. pylori eradication therapy has been administered.

Prediction of the invasion depth of superficial nonampullary duodenal adenocarcinoma

OBJECTIVES

Distinguishing between intramucosal cancer and submucosal invasive cancer is vital for optimal treatment selection for patients with superficial nonampullary duodenal adenocarcinoma (SNADAC); however, standard diagnostic systems for diagnosing invasion depth are as yet undetermined.

METHODS

Of 205 patients with SNADAC who underwent treatment at our institution between 2006 and 2022, 188 had intramucosal cancer and 17 had submucosal invasive cancer. The clinical, endoscopic, and pathological features used in the preoperative diagnosis of invasion depth and the diagnostic performance of endoscopic ultrasonography (EUS) were retrospectively analyzed in 85 patients.

RESULTS

The oral side of the papilla tumor location, protruded or mixed macroscopic type, and moderately-to-poorly differentiated adenocarcinoma based on biopsy specimens were significantly more frequent in submucosal invasive cancer than in intramucosal cancer (88% vs. 48%; 94% vs. 42%; 47% vs. 0%, respectively). From the relationship between the endoscopic features and the submucosal invasive cancer incidence, submucosal invasion risk was stratified as: (i) low-risk (risk, 2%), all lesions located on the anal side of the papilla and superficial macroscopic type on the oral side of the papilla; and (ii) high-risk (risk, 23%), protruded or mixed macroscopic type on the oral side of the papilla. Based on the biopsy specimens, all eight patients with moderately-to-poorly differentiated adenocarcinoma had submucosal invasive cancer. Furthermore, EUS was not associated with invasion depth's diagnostic accuracy improvements.

CONCLUSION

Optimal treatment indications for SNADAC can be selected based on the risk factors of submucosal invasion by tumor location, macroscopic type, and biopsy diagnosis.

Efficacy and Safety of Self-Expandable Metallic Stent Placement for Malignant Esophageal Fistula

Patients with malignant esophageal fistulas often experience dysphagia and infection, resulting in poor prognoses. Self-expandable metallic stent (SEMS) placement is a palliative treatment option; however, its efficacy and safety are unclear. We aimed to determine the efficacy and safety of SEMS placement for malignant esophageal fistulas. We retrospectively investigated patients who underwent SEMS placement for malignant esophageal fistulas between 2013 and 2022 at the Cancer Institute Hospital. Dysphagia scores (DSs) before and after SEMS placement, adverse events, and overall survival from SEMS placement until death were evaluated. A total of 17 patients underwent SEMS placement, including 12 and 5 patients with esophageal and lung cancers, respectively. Prior treatments included chemoradiotherapy (n = 11), radiotherapy (n = 4), and chemotherapy (n = 4); two patients underwent palliative radiotherapy after chemotherapy. All procedures were technically successful. After SEMS placement, 14 (82.4%) patients were able to consume semisolid or solid food (DS ≤ 2). Major adverse events were encountered in only one case. The median survival time after SEMS placement was 71 days (range 17-247 days). SEMS placement allowed most patients to resume oral intake with a low rate of major adverse events. SEMS placement is a reasonable palliative treatment option for patients with malignant fistulas who have poor prognoses.

Clinicopathological characteristics of advanced gastric cancer after Helicobacter pylori eradication

Background and Aim

Helicobacter pylori (H. pylori) eradication has become popular as it prevents the development of gastric cancer. There have been no comprehensive studies on advanced gastric cancer (AGC) after eradication; thus, the clinical characteristics remain unclear. This study aimed to compare the characteristics of AGC after eradication and with current H. pylori infection and evaluate the esophagogastroduodenoscopy (EGD) follow-up after eradication.

Methods

This single-center, retrospective study included 261 consecutive patients diagnosed with AGC through EGD. The patients were grouped based on their H. pylori status: eradication (n = 48) and infection (n = 213) groups. Univariate analysis was conducted to compare clinicopathological characteristics between groups. The clinical course of the eradication group was analyzed by dividing the patients into three groups according to the interval from the last EGD until AGC detection: short-interval (<1 year), intermediate-interval (2-3 years), and long-interval (4-5 years) groups.

Results

The radical resection (R0) rate was higher in the eradication group. In surgical cases, the median tumor diameter was shorter in the eradication group. Analysis of EGD surveillance after eradication in 36 available cases showed that 24 (66.7%) were detected within 5 years after eradication, and 3 (8.3%) were diagnosed as AGC > 20 years after eradication. The R0 rates in the short-, intermediate-, and long-interval groups were 83.3%, 71.4%, and 60%, respectively.

Conclusions

AGC after eradication was more often detected at the phase in which R0 resection was possible. EGD follow-up with tight intervals of at least 5 years after eradication is advisable.

Genomic features of Helicobacter pylori-naïve diffuse-type gastric cancer

Helicobacter pylori (HP) is a major etiologic driver of diffuse-type gastric cancer (DGC). However, improvements in hygiene have led to an increase in the prevalence of HP-naïve DGC; that is, DGC that occurs independent of HP. Although multiple genomic cohort studies for gastric cancer have been conducted, including studies for DGC, distinctive genomic differences between HP-exposed and HP-naïve DGC remain largely unknown. Here, we employed exome and RNA sequencing with immunohistochemical analyses to perform binary comparisons between 36 HP-exposed and 27 HP-naïve DGCs from sporadic, early-stage, and intramucosal or submucosal tumor samples. Among the samples, 33 HP-exposed and 17 HP-naïve samples had been preserved as fresh-frozen samples. HP infection status was determined using stringent criteria. HP-exposed DGCs exhibited an increased single nucleotide variant burden (HP-exposed DGCs; 1.97 [0.48-7.19] and HP-naïve DGCs; 1.09 [0.38-3.68] per megabase; p = 0.0003) and a higher prevalence of chromosome arm-level aneuploidies (p < 0.0001). CDH1 was mutated at similar frequencies in both groups, whereas the RHOA-ARHGAP pathway misregulation was exclusive to HP-exposed DGCs (p = 0.0167). HP-exposed DGCs showed gains in chromosome arms 8p/8q (p < 0.0001), 7p (p = 0.0035), and 7q (p = 0.0354), and losses in 16q (p = 0.0167). Immunohistochemical analyses revealed a higher expression of intestinal markers such as CD10 (p < 0.0001) and CDX2 (p = 0.0002) and a lower expression of the gastric marker, MUC5AC (p = 0.0305) among HP-exposed DGCs. HP-naïve DGCs, on the other hand, had a purely gastric marker phenotype. This work reveals that HP-naïve and HP-exposed DGCs develop along different molecular pathways, which provide a basis for early detection strategies in high incidence settings. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Early Esophageal Adenocarcinoma with Non-Barrett's Columnar Epithelium Origin: Two Case Reports and a Literature Review

We herein report two cases of early esophageal adenocarcinoma derived from non-Barrett's columnar epithelium. Both patients, a 65-year-old woman and 60-year-old man, had elevated lesions on white-light imaging. Magnifying endoscopy revealed slightly irregular surface and vessel patterns, and both patients were successfully treated with endoscopic submucosal dissection. Histopathologically, both lesions comprised of well-differentiated gastric mucin phenotype adenocarcinoma. One lesion was accompanied by ectopic gastric mucosa, but the other was speculated to be ectopic gastric mucosa according to the tumor locus at the upper thoracic esophagus. Despite its rarity, endoscopists should consider the existence of adenocarcinoma derived from non-Barrett's columnar epithelium.

Safety and Efficacy of Self-Expandable Metallic Stent Placement Using Low Radial Force Stent for Malignant Dysphagia after Radiotherapy

INTRODUCTION

We aimed to investigate the safety and efficacy of self-expandable metallic stent (SEMS) placement in patients with prior radiotherapy (RT) using the Niti-S stent, which is characterized by low radial force, in comparison to patients without prior RT.

METHODS

A consecutive series of 83 patients who were treated by SEMS placement using Niti-S stent for severe malignant esophageal obstruction or fistula were enrolled. The adverse event rates and efficacy were retrospectively compared between patients with/without prior RT before SEMS placement (RT group [n = 32] versus non-RT group [n = 51]).

RESULTS

The incidence rate of major adverse events in the RT group was 6.3% and was not significantly different from that in the non-RT group (5.9%, p = 0.95). Among the RT group, 84.4% were able to resume oral intake within a median of 2 days. Among the patients with fistula, 78.6% could resume oral intake and survive for 73 days after SEMS placement. Cox proportional hazard regression analysis identified significant factors affecting overall survival to be prior RT (hazard ratio [HR]: 1.96), low performance status (HR: 3.87), and subsequent anticancer treatment after SEMS placement (HR: 0.41). However, compared to the non-RT group, the RT group had received longer duration of anticancer treatment before SEMS placement and a lower rate of subsequent anticancer treatment after SEMS placement.

CONCLUSIONS

With the Niti-S stent, the incidence of major adverse events was sufficiently low even for patients after RT. SEMS with low radial force would be an effective palliative treatment option for patients, regardless of prior RT.

Long-term outcomes of esophageal squamous cell carcinoma with invasion depth of pathological T1a-muscularis mucosae and T1b-submucosa by endoscopic resection followed by appropriate additional treatment

OBJECTIVES

Endoscopic resection (ER) is indicated for a wide range of superficial esophageal squamous cell carcinomas (ESCCs). We examined the long-term outcomes in patients with pathological (p) invasion of ESCC into the T1a-muscularis mucosae (MM) and T1b-submucosa (SM) after ER, for which data on prognosis are limited.

METHODS

Of the 1217 patients with superficial ESCC who underwent ER, 225 patients with a pathological diagnosis of ESCC invasion into the MM, minute submucosal invasion ≤200 µm (SM1), or massive submucosal invasion (SM2) were included. In patients with lymphovascular invasion, droplet infiltration, or SM2 invasion, additional treatments, including chemoradiation (CRT) or esophagectomy with two- to three-field lymph node dissection, were recommended. The median observation period was 66 months (interquartile range 48-91 months).

RESULTS

In total, there were 151, 28, and 46 pT1a-MM, pT1b-SM1, and pT1b-SM2 cases, respectively. Metastatic recurrence was observed in 1.3%, 10.7%, and 6.5% patients with pT1a-MM, pT1b-SM1, and pT1b-SM2 ESCCs, respectively. Of the eight patients with metastatic recurrence, six were successfully treated, and two died of ESCC. The 5-year overall survival rates were 84.1%, 71.4%, and 67.4%, the 5-year relapse-free survival rates were 82.8%, 64.3%, and 65.2%, and the 5-year disease-specific survival rates were 100%, 96.4%, and 99.1% in patients with pT1a-MM, pT1b-SM1, and pT1b-SM2 ESCCs, respectively. Multivariate analysis showed that additional CRT and esophagectomy, and T1b-SM2 were positively and negatively associated with overall survival, respectively.

CONCLUSIONS

Endoscopic resection preceding appropriate additional treatments resulted in favorable outcomes. Many cases of metastatic recurrence in this cohort could be successfully treated.

Additive effect of evaluating microsurface and microvascular patterns using magnifying endoscopy with narrow-band imaging in gastric cancer: a post-hoc analysis of a single-center observational study

Background

No studies have compared the performance of microvascular and microsurface patterns alone with their combination in patients undergoing magnifying endoscopy with narrow-band imaging for diagnosing gastric cancer. This study aimed to clarify the differences in diagnostic performance among these methods.

Methods

Thirty-three participating endoscopists who had received specialized training in magnifying endoscopy evaluated the microvascular and microsurface patterns of images of 106 cancerous and 106 non-cancerous lesions. If classified as “irregular,” the lesion was diagnosed as gastric cancer. To evaluate diagnostic performance, we compared the diagnostic accuracy, sensitivity, and specificity of these methods.

Results

Performance-related items did not differ significantly between microvascular and microsurface patterns. However, the diagnostic accuracy and sensitivity were significantly higher when using a combination of these methods than when using microvascular (82.1% [76.4–86.7] vs. 76.4% [70.3–81.6] and 69.8% [60.5–77.8] vs. 63.2% [53.7–71.8]; P < 0.001 and P = 0.008, respectively) or microsurface (82.1% [76.4–86.7] vs. 73.6% [67.3–79.1] and 69.8% [60.5–77.8] vs. 52.8% [43.4‒62.1]; both, P < 0.001) patterns alone. The additive effect on diagnostic accuracy and sensitivity was 5.7‒8.6% and 6.6‒17.0%, respectively.

Conclusions

We demonstrate the superiority of the combination of microvascular and microsurface patterns over microvascular or microsurface patterns alone for diagnosing gastric cancer. Our data support the use of the former method in clinical practice. Although a major limitation of this study was its retrospective, single-center design, our findings may help to improve the diagnosis of gastric cancer.

Sporadic non-ampullary duodenal adenoma with low-grade dysplasia: Natural history and clinical management

Background and study aims  Management strategies for sporadic non-ampullary duodenal adenoma with low-grade dysplasia (LGD) are not well established. This study aimed to analyze progression factors and determine suitable treatment strategies for LGD lesions. Patients and methods  We retrospectively analyzed consecutive LGD lesions (n = 125) in patients followed up for ≥ 6 months (median, 45 months) and evaluated the changes in clinicopathological features during follow-up. All LGD lesions were classified into two groups: stable LGD (no increase or < 5 mm increase in tumor size, with unchanged histological dysplasia grade) and progressive LGD (≥ 5 mm increase in tumor size and/or progression to high-grade dysplasia or adenocarcinoma). Results  Eighty-six LGD were classified as stable and 39 as progressive. Location on the oral side of the papilla of Vater, large initial tumor size ( ≥ 10 mm), macroscopically complex type, red color, and nodularity were significantly frequent in progressive LGD than in stable LGD. In multivariate analysis, large initial tumor size (odds ratio [OR], 10.2; 95 % confidence interval [CI], 3.3-32.1; P  < 0.001) and location on the oral side of the papilla of Vater (OR: 1.8, 95 % CI: 1.4-12.5; P  = 0.012) were significant factors for progression. Moreover, initial tumor size < 5 mm rarely progressed (0%-3.9 %); however, initial tumor size ≥ 20 mm and 10-19 mm located on the oral side of the papilla of Vater had a high-risk progression rate (75.0-85.7 %). Conclusions  According to the risk stratification of progression factors by initial tumor size and location, we can determine suitable treatment indications for LGD lesions.

Evaluation of Microvascular Patterns Alone Using Endocytoscopy with Narrow-Band Imaging for Diagnosing Gastric Cancer

INTRODUCTION

Although endocytoscopy (EC) with narrow-band imaging (NBI) is effective in diagnosing gastric cancer, no diagnostic system has been validated. We explored a specific diagnostic system for gastric cancer using EC with NBI.

METHODS

Equal numbers of images from cancerous and noncancerous areas (114 images each) were assessed by endoscopists with (development group: 33) and without (validation group: 28) specific training in magnifying endoscopy with NBI. Microvascular and microsurface patterns (MS) in each image were evaluated. Lesions were diagnosed as cancerous when patterns were deemed "irregular." The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of a diagnosis according to patterns on EC with NBI (microvascular pattern [MV] alone, MS alone, and both) were evaluated and compared between groups to determine the diagnostic performance.

RESULTS

In the development and validation groups, diagnoses based on the MV alone had significantly higher accuracy (91.7% vs. 76.3%, p < 0.0001 and 92.5% vs. 67.5%, p < 0.0001, respectively) and sensitivity (88.6% vs. 68.3%, p < 0.0001 and 89.5% vs. 38.6%, p < 0.0001, respectively) than those based on the MS alone. In both groups, there were no significant differences in diagnostic accuracy between using the MV alone and both patterns.

DISCUSSION/CONCLUSION

Evaluation of the MV alone is a simple and accurate diagnostic method for gastric cancer. This system could find widespread applications in clinical practice.

A novel diagnostic system for superficial nonampullary duodenal epithelial tumors sized ≤ 5 mm

BACKGROUND

An association between specific endoscopic findings and high-grade dysplasia/carcinoma in superficial nonampullary duodenal epithelial tumors ≤ 5 mm in size has not been reported. We sought to identify the endoscopic findings associated with high-grade dysplasia/carcinoma in patients with superficial nonampullary duodenal epithelial tumors ≤ 5 mm.

METHODS

We retrospectively assessed the data of 84 patients (88 lesions; low-grade dysplasia: n = 35, high-grade dysplasia/carcinoma: n = 53) with superficial nonampullary duodenal epithelial tumors who underwent initial treatment at a single center (from July 2009 to April 2021). All the patients had lesions sized ≤ 5 mm. We assumed that the endoscopic findings were independently associated with high-grade dysplasia/carcinoma and determined the accuracy, sensitivity, and specificity of a combination of independent factors for diagnosing high-grade dysplasia/carcinoma and low-grade dysplasia.

RESULTS

Multivariate logistic regression of significant factors in the univariate analysis revealed that lesions with depressed morphology (odds ratio: 23.9, 95% confidence interval: 2.8-204.2; p = 0.0037) and a reddish color (odds ratio: 175.7, 95% confidence interval: 11.4-2697.1; p = 0.0002) were independently associated with high-grade dysplasia/carcinoma. McNemar's test revealed that combining the macroscopic type and color provided significantly higher sensitivity for diagnosing high-grade dysplasia/carcinoma than color alone (98.1%, 95% confidence interval: 90.1-99.7 vs. 71.7%, 95% confidence interval: 58.4-82.0; p = 0.0002).

CONCLUSIONS

Reddish and depressed-type lesions before treatment were associated with high-grade dysplasia/carcinoma. Combining the macroscopic type and color can help detect high-grade dysplasia/carcinoma. These findings could help clinicians determine the best therapeutic strategy for patients with smaller (≤ 5 mm) superficial nonampullary duodenal epithelial tumors in clinical settings.

Artificial intelligence diagnostic system predicts multiple Lugol-voiding lesions in the esophagus and patients at high risk for esophageal squamous cell carcinoma

BACKGROUND

It is known that an esophagus with multiple Lugol-voiding lesions (LVLs) after iodine staining is high risk for esophageal cancer; however, it is preferable to identify high-risk cases without staining because iodine causes discomfort and prolongs examination times. This study assessed the capability of an artificial intelligence (AI) system to predict multiple LVLs from images that had not been stained with iodine as well as patients at high risk for esophageal cancer.

METHODS

We constructed the AI system by preparing a training set of 6634 images from white-light and narrow-band imaging in 595 patients before they underwent endoscopic examination with iodine staining. Diagnostic performance was evaluated on an independent validation dataset (667 images from 72 patients) and compared with that of 10 experienced endoscopists.

RESULTS

The sensitivity, specificity, and accuracy of the AI system to predict multiple LVLs were 84.4 %, 70.0 %, and 76.4 %, respectively, compared with 46.9 %, 77.5 %, and 63.9 %, respectively, for the endoscopists. The AI system had significantly higher sensitivity than 9/10 experienced endoscopists. We also identified six endoscopic findings that were significantly more frequent in patients with multiple LVLs; however, the AI system had greater sensitivity than these findings for the prediction of multiple LVLs. Moreover, patients with AI-predicted multiple LVLs had significantly more cancers in the esophagus and head and neck than patients without predicted multiple LVLs.

CONCLUSION

The AI system could predict multiple LVLs with high sensitivity from images without iodine staining. The system could enable endoscopists to apply iodine staining more judiciously.

Efficacy of endoscopic filling with polyglycolic acid sheets and fibrin glue for anastomotic leak after esophageal cancer surgery: identification of an optimal technique

BACKGROUND

Anastomotic leak is a potentially life-threatening complication following esophageal cancer surgery. In this study, we aimed to clarify the efficacy of endoscopic filling with polyglycolic acid (PGA) sheets and fibrin glue for anastomotic leak after esophageal cancer surgery.

METHODS

Consecutive patients who underwent endoscopic filling with PGA sheets and fibrin glue for anastomotic leak after esophageal cancer surgery between August 2014 and January 2020 were included in the study, with its efficacy retrospectively reviewed. We performed endoscopic filling using two methods: (1) filling the fistula with PGA sheets, followed by the application of a fibrinogen and thrombin solution (conventional method) and (2) filling the fistula with PGA sheets pre-soaked in a fibrinogen solution, followed by the application of a thrombin solution (pre-soak method).

RESULTS

A total of 14 patients underwent endoscopic filling procedures within the study period. The endoscopic filling procedures were successfully performed in all cases and no adverse events associated with the procedures were observed. Fistula closure was obtained in 10 (71%) cases. In the 10 successful cases, the median number of procedures was 1 (range 1-3) and the median time from the first procedure to oral intake was 7.5 days (range 4-36 days). The success rate of the pre-soak method was significantly higher than that of the conventional method (90% vs. 25%, P = 0.041).

CONCLUSIONS

Endoscopic filling with PGA sheets and fibrin glue is a safe and effective treatment for the closure of an anastomotic leak. The pre-soak method can achieve successful endoscopic filling.

Usefulness of the l-type Wako Helicobacter pylori antibody J test

Background and Aim

Helicobacter pylori antibody levels in the blood are currently measured using an ELISA. In April 2016, FUJIFILM Wako Pure Chemical Corporation launched the “l‐type Wako Helicobacter pylori antibody J" test, which is based on the latex agglutination turbidimetric immunoassay. In this study, we investigated the usefulness of the Wako test.

Methods

We measured H. pylori antibody levels using both the ELISA and Wako test in 180 patients who underwent upper gastrointestinal endoscopy at our hospital between September 2017 and February 2019. Ninety patients were infected with H. pylori. We calculated the diagnostic accuracy, sensitivity, and specificity of each test and the concordance rate between the ELISA and Wako test. If lower limits of 90% confidence intervals (CIs) for each diagnostic validity exceeded the 85% threshold, the usefulness of the diagnostic test was confirmed.

Results

The diagnostic accuracy, sensitivity, and specificity were 94.4% (90% CI, 90.8–97.0%), 94.4% (90% CI, 88.7–97.8%), and 94.4% (90% CI, 88.7–97.8%), respectively, when the Wako test was used, and 94.4% (90% CI, 90.8–97.0%), 88.9% (90% CI, 81.9–93.8%), and 100% (90% CI, 96.0–100%), respectively, when the ELISA was used. The concordance rate between the two tests was high (κ = 0.8444).

Conclusions

We confirmed the usefulness of the Wako test, especially when screening for H. pylori infection, due to its high sensitivity.

Effect of spraying l-menthol on peristalsis resumption during endoscopic submucosal dissection of gastric tumors

Background and Aim

l‐Menthol has smooth muscle‐relaxing and antiperistaltic effects. We examined its effectiveness against peristalsis resumption during endoscopic submucosal dissection (ESD) of gastric tumors.

Methods

We retrospectively examined clinical data of 485 patients (501 lesions) who underwent ESD for upper gastrointestinal tumors in 2017. We included 119 patients (127 lesions) in whom peristaltic movement resumed during ESD and l‐menthol was applied; 366 patients (374 lesions) without l‐menthol application were used as controls. Video recordings were reviewed to determine whether l‐menthol suppressed peristalsis resumption.

Results

In cases with l‐menthol application, 2 (2.9%), 36 (14.3%), and 89 (71.2%) lesions were found in the upper (U), middle (M), and lower (L) regions, respectively. In the control group, the corresponding values were 66 (17.6%), 215 (57.5%), and 93 (24.9%), respectively. l‐Menthol efficacy was observed in 116 of the 127 treated lesions (91.3%), over 90% of which were in the posterior wall of the U region, anterior wall and greater curvature of the M region, and anterior wall and lesser curvature of the L region. The most and least effective areas for l‐menthol application were the anterior wall of gastric antrum and posterior wall of the M region, respectively. The mean time from application to peristalsis inhibition was 8.7 s. No adverse effects were observed; perforation and secondary hemorrhage were not significantly different between the groups.

Conclusion

Direct l‐menthol application to the submucosal layer during mucosal resection affects smooth muscles and rapidly inhibits peristalsis resumption. Clinically, l‐Menthol can be used to suppress peristalsis recurrence during ESD, without adverse effects.

Clinical outcomes of endoscopic resection of preoperatively diagnosed non-circumferential T1a-muscularis mucosae or T1b-submucosa 1 esophageal squamous cell carcinoma

In Japan, preoperatively diagnosed T1a-muscularis mucosae or T1b-submucosa 1 (MM/SM1) esophageal squamous cell carcinoma (ESCC) is a relative indication for endoscopic resection (ER). We evaluated long-term outcomes in patients after ER for non-circumferential ESCC with a preoperative diagnosis of MM/SM1 invasion. We retrospectively reviewed 66 patients with a preoperative diagnosis of non-circumferential MM/SM1 ESCC endoscopically resected between 2010 and 2015. Patients were divided into low- (adequate follow-up) and high-risk (requiring additional treatment) groups for lymph node metastasis according to risk factors (submucosal invasion, lymphovascular invasion, or droplet infiltration) and long-term outcomes were analyzed. Pathological invasion to T1a-lamina propria mucosa, MM/SM1, and T1b-SM2 was seen in 22, 38, and 6 lesions, respectively. Overall, 71.2% patients were classified into the "adequate follow-up" group. Of these, only one patient had a lymph node recurrence, which was successfully treated by additional therapy. The remaining 28.8% patients were classified into the "requiring additional treatment" group, where no recurrences were observed after additional treatments. After a median follow-up of 58.6 months, no deaths happened due to ESCC. The 3- and 5-year overall survival rates were 93.6% and 88.7%, respectively. ER is a valid initial treatment for non-circumferential ESCC with preoperatively diagnosed MM/SM1 invasion.

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-based diagnostic system classifying gastric cancers and ulcers: comparison between the original and newly developed systems

BACKGROUND

We previously reported for the first time the usefulness of artificial intelligence (AI) systems in detecting gastric cancers. However, the "original convolutional neural network (O-CNN)" employed in the previous study had a relatively low positive predictive value (PPV). Therefore, we aimed to develop an advanced AI-based diagnostic system and evaluate its applicability for the classification of gastric cancers and gastric ulcers.

METHODS

We constructed an "advanced CNN" (A-CNN) by adding a new training dataset (4453 gastric ulcer images from 1172 lesions) to the O-CNN, which had been trained using 13 584 gastric cancer and 373 gastric ulcer images. The diagnostic performance of the A-CNN in terms of classifying gastric cancers and ulcers was retrospectively evaluated using an independent validation dataset (739 images from 100 early gastric cancers and 720 images from 120 gastric ulcers) and compared with that of the O-CNN by estimating the overall classification accuracy.

RESULTS

The sensitivity, specificity, and PPV of the A-CNN in classifying gastric cancer at the lesion level were 99.0 % (95 % confidence interval [CI] 94.6 %-100 %), 93.3 % (95 %CI 87.3 %-97.1 %), and 92.5 % (95 %CI 85.8 %-96.7 %), respectively, and for classifying gastric ulcers were 93.3 % (95 %CI 87.3 %-97.1 %), 99.0 % (95 %CI 94.6 %-100 %), and 99.1 % (95 %CI 95.2 %-100 %), respectively. At the lesion level, the overall accuracies of the O- and A-CNN for classifying gastric cancers and gastric ulcers were 45.9 % (gastric cancers 100 %, gastric ulcers 0.8 %) and 95.9 % (gastric cancers 99.0 %, gastric ulcers 93.3 %), respectively.

CONCLUSION

The newly developed AI-based diagnostic system can effectively classify gastric cancers and gastric ulcers.

Performance of a computer-aided diagnosis system in diagnosing early gastric cancer using magnifying endoscopy videos with narrow-band imaging (with videos)

BACKGROUND AND AIMS

The performance of magnifying endoscopy with narrow-band imaging (ME-NBI) using a computer-aided diagnosis (CAD) system in diagnosing early gastric cancer (EGC) is unclear. Here, we aimed to clarify the differences in the diagnostic performance between expert endoscopists and the CAD system using ME-NBI.

METHODS

The CAD system was pretrained using 1492 cancerous and 1078 noncancerous images obtained using ME-NBI. One hundred seventy-four videos (87 cancerous and 87 noncancerous videos) were used to evaluate the diagnostic performance of the CAD system using the area under the curve (AUC), accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). For each item, comparisons were made between the CAD system and 11 experts who were skilled in diagnosing EGC using ME-NBI with clinical experience of more than 1 year at our hospital.

RESULTS

The CAD system demonstrated an AUC of 0.8684. The accuracy, sensitivity, specificity, PPV, and NPV were 85.1% (95% confidence interval [95% CI], 79.0-89.6), 87.4% (95% CI, 78.8-92.8), 82.8% (95% CI, 73.5-89.3), 83.5% (95% CI, 74.6-89.7), and 86.7% (95% CI, 77.8-92.4), respectively. The CAD system was significantly more accurate than 2 experts, significantly less accurate than 1 expert, and not significantly different from the remaining 8 experts.

CONCLUSIONS

The overall performance of the CAD system using ME-NBI videos in diagnosing EGC was considered good and was equivalent to or better than that of several experts. The CAD system may prove useful in the diagnosis of EGC in clinical practice.

Application of artificial intelligence using convolutional neural networks in determining the invasion depth of esophageal squamous cell carcinoma

OBJECTIVES

In Japan, endoscopic resection (ER) is often used to treat esophageal squamous cell carcinoma (ESCC) when invasion depths are diagnosed as EP-SM1, whereas ESCC cases deeper than SM2 are treated by surgical operation or chemoradiotherapy. Therefore, it is crucial to determine the invasion depth of ESCC via preoperative endoscopic examination. Recently, rapid progress in the utilization of artificial intelligence (AI) with deep learning in medical fields has been achieved. In this study, we demonstrate the diagnostic ability of AI to measure ESCC invasion depth.

METHODS

We retrospectively collected 1751 training images of ESCC at the Cancer Institute Hospital, Japan. We developed an AI-diagnostic system of convolutional neural networks using deep learning techniques with these images. Subsequently, 291 test images were prepared and reviewed by the AI-diagnostic system and 13 board-certified endoscopists to evaluate the diagnostic accuracy.

RESULTS

The AI-diagnostic system detected 95.5% (279/291) of the ESCC in test images in 10 s, analyzed the 279 images and correctly estimated the invasion depth of ESCC with a sensitivity of 84.1% and accuracy of 80.9% in 6 s. The accuracy score of this system exceeded those of 12 out of 13 board-certified endoscopists, and its area under the curve (AUC) was greater than the AUCs of all endoscopists.

CONCLUSIONS

The AI-diagnostic system demonstrated a higher diagnostic accuracy for ESCC invasion depth than those of endoscopists and, therefore, can be potentially used in ESCC diagnostics.

Convolutional Neural Network for Differentiating Gastric Cancer from Gastritis Using Magnified Endoscopy with Narrow Band Imaging

BACKGROUND

Early detection of early gastric cancer (EGC) allows for less invasive cancer treatment. However, differentiating EGC from gastritis remains challenging. Although magnifying endoscopy with narrow band imaging (ME-NBI) is useful for differentiating EGC from gastritis, this skill takes substantial effort. Since the development of the ability to convolve the image while maintaining the characteristics of the input image (convolution neural network: CNN), allowing the classification of the input image (CNN system), the image recognition ability of CNN has dramatically improved.

AIMS

To explore the diagnostic ability of the CNN system with ME-NBI for differentiating between EGC and gastritis.

METHODS

A 22-layer CNN system was pre-trained using 1492 EGC and 1078 gastritis images from ME-NBI. A separate test data set (151 EGC and 107 gastritis images based on ME-NBI) was used to evaluate the diagnostic ability [accuracy, sensitivity, positive predictive value (PPV), and negative predictive value (NPV)] of the CNN system.

RESULTS

The accuracy of the CNN system with ME-NBI images was 85.3%, with 220 of the 258 images being correctly diagnosed. The method's sensitivity, specificity, PPV, and NPV were 95.4%, 71.0%, 82.3%, and 91.7%, respectively. Seven of the 151 EGC images were recognized as gastritis, whereas 31 of the 107 gastritis images were recognized as EGC. The overall test speed was 51.83 images/s (0.02 s/image).

CONCLUSIONS

The CNN system with ME-NBI can differentiate between EGC and gastritis in a short time with high sensitivity and NPV. Thus, the CNN system may complement current clinical practice of diagnosis with ME-NBI.

[Endoscopic Diagnosis Using Artificial Intelligence]

Image recognition using artificial intelligence(AI)has developed dramatically with innovative technologies such as machine learning and deep learning. Currently, it is considered that AI has exceeded human ability in image recognition. In the field of endoscopic diagnosis, development of computer-aided diagnosis(CAD)systems using AI is progressing. The CAD is expected to help endoscopists improve detection and characterization of polyp, cancer, and inflamation in all digestive area. Some CAD systemes showing ability better than endoscopists have been reported. It may be well applicable to daily clinical practice as real time endoscopic diagnosis in the near future.

AN ATTEMPT TO DETERMINE POSITIONS OF AEROSOL SOURCE BY THE PIXE ANALYSIS

Aerosols were continuously collected for 2 or 3 hours during the periods of 4-27 August 1997 and of 23 March-2 April 1998 at a suburb of Sendai City (east 10 km from Sendai), and meteorological data such as wind directions, wind velocities, etc were measured at the same time. The collected aerosol samples were analyzed by the particle-induced X-ray emission (PIXE) method. Fourteen elements (S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Hg and Pb) were contained in these samples. The elemental concentrations increased in the daytime and decreased at night. It coincided with the time variation of people movement. The concentrations of Mn, Fe, Zn and Pb elements depended strongly on the direction of wind and their distributions for wind directions reflected to the position of aerosol sources. This result suggests that the position of aerosol source can be determined by measuring aerosols and wind directions at the many positions.