Quantification of crystallinity during indomethacin crystalline transformation from α- to γ-polymorphic forms and of the thermodynamic contribution to dissolution in aqueous buffer and solutions of solubilizer.

The thermodynamic properties and dissolution of indomethacin (INM) were analyzed as models for poorly water-soluble drugs. Physical mixtures of the most stable γ-form and metastable α-form of INM at various proportions were prepared, and their individual signal intensities proportional to their mole fractions were observed using X-ray powder diffraction and Fourier transform infrared spectrometry at standard temperature. The endothermic signals of the α-form, with a melting point of 426 K, and that of the γ-form, with a melting point of 433 K, were obtained by differential scanning calorimetry (DSC). Furthermore, an exothermic DSC peak of the α/γ-phase transition at approximately 428 K was obtained. As we computed the melting entropy of the α-form and that of its transformation, the frequency of the transition was quantitatively determined, which indicated the maximum of the α/γ-phase transition at an α-form proportion of 68%. Subsequently, the thermodynamic contributions of the α- and γ-forms were analyzed using a Van't Hoff plot for solubility in aqueous solutions at pH 6.8. The dissolution enthalpies for α- and γ-forms were 28.2 and 31.2 kJ mol-1, respectively, which are in agreement with the quantitative contribution predicted by the product of the temperature and melting entropy. The contribution of melting entropy was conserved in different dissolution processes with aqueous solvents containing lidocaine, diltiazem, l-carnosine, and aspartame as solubilizers; their γ-form Setschenow coefficients were -39.6, +82.9, -17.3, and +23.2, whereas those of the α-form were -39.7, +80.4, -16.7, and +22.7, respectively. We conclude that the dissolution ability of the solid state and solubilizers indicate their additivity independently.

Nicotinic acetylcholine receptor activation induces BACE1 transcription via the phosphorylation and stabilization of nuclear SP1.

Epidemiological studies have shown that cigarette smoking increases the risk of Alzheimer disease. However, inconsistent results have been reported regarding the effects of smoking or nicotine on brain amyloid ß (Aß) deposition. In this study, we found that stimulation of the nicotinic acetylcholine receptor (nAChR) increased Aß production in mouse brains and cultured neuronal cells. nAChR activation triggered the MEK/ERK pathway, which then phosphorylated and stabilized nuclear SP1. Upregulated SP1 acted on two recognition motifs in the BACE1 gene to induce its transcription, resulting in enhanced Aß production. Mouse brain microdialysis revealed that nAChR agonists increased Aß levels in the interstitial fluid of the cerebral cortex but caused no delay of Aß clearance. In vitro assays indicated that nicotine inhibited Aß aggregation. We also found that nicotine modified the immunoreactivity of anti-Aß antibodies, possibly through competitive inhibition and Aß conformation changes. Using anti-Aß antibody that was carefully selected to avoid these effects, we found that chronic nicotine treatment in Aß precursor protein knockin mice increased the Aß content but did not visibly change the aggregated Aß deposition in the brain. Thus, nicotine influences brain Aß deposition in the opposite direction, thereby increasing Aß production and inhibiting Aß aggregation.

Using singular value decomposition to analyze drug/ß-cyclodextrin mixtures: insights from X-ray powder diffraction patterns.

The article discusses the use of mathematical models and linear algebra to understand the crystalline structures and interconversion pathways of drug complexes with ß-cyclodextrin (ß-CD). It involved the preparation and analysis of mixtures of indomethacin, diclofenac, famotidine, and cimetidine with ß-CD using techniques such as differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and proton nuclear magnetic resonance (1H-NMR). Singular value decomposition (SVD) analysis is used to identify the presence of different polymorphs in the mixtures of these drugs and ß-CD, determine interconversion pathways, and distinguish between different forms. In general, linear algebra or artificial intelligence (AI) is used to approximate the contribution of distinguishable entities to various phenomena. We expected linear algebra to completely reveal all eight entities present in the diffractogram dataset. However, after performing the SVD procedure, we found that only six independent basis functions were extracted, and the entities of the INM α-form and the CIM B-form were not included. It is considered that this is due to that data processing is limited to revealing only six or seven independent factors, as it is a small world. The authors caution that these may not always reproduce or approach reality in complicated real-world situations.

The effect of antithrombotic drug use on delayed bleeding with esophageal endoscopic resection.

BACKGROUND AND AIM: Whether antithrombotic drugs increase the risk of post-esophageal endoscopic resection bleeding is unknown. This study examined the effect of antithrombotic drugs, aspirin, thienopyridine, direct oral anticoagulants (DOAC), and warfarin, on post-esophageal endoscopic resection bleeding. METHODS: We enrolled 957 patients (1202 esophageal tumors) treated with endoscopic resection and classified them based on antithrombotic drug use as no use, aspirin, thienopyridine, DOAC, and warfarin. Patients using antiplatelet drugs (i.e. aspirin and thienopyridine) were further sub-classified based on their continued or discontinued use before endoscopic resection. The bleeding rates were compared between these groups to assess the effects of antithrombotic drug use and interruption of antiplatelet therapy on post-esophageal endoscopic resection bleeding. RESULTS: The post-endoscopic resection bleeding rate was 0.3% (95% CI, 0.1-1) in the group without antithrombotic drug use, 4.5% (95% CI, 0.1-23) in the aspirin-continued group, 2.9% (95% CI, 0.1-15) in the aspirin-discontinued group, 0% (95% CI, 0-78) in the replaced thienopyridine with aspirin group, 0% (95% CI, 0-26) in the thienopyridine-discontinued group, 13% (95% CI, 1.6-38) in the DOAC group, and 0% (95% CI, 0-45) in the warfarin group. The post-endoscopic resection bleeding rate in the DOAC group was significantly higher than that in the group without antithrombotic drugs (P = 0.003). The post-endoscopic resection bleeding rates did not differ between the other groups. CONCLUSIONS: Our results suggest that discontinuing aspirin is not necessary for esophageal endoscopic resection while we must be careful regarding DOAC.

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.

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.

Structural study of the recognition mechanism of tau antibody Tau2r3 with the key sequence (VQIINK) in tau aggregation.

One of the histopathological features of Alzheimer's disease (AD) is higher order neurofibrillary tangles formed by abnormally aggregated tau protein. The sequence 275VQIINK280 in the microtubule-binding domain of tau plays a key role in tau aggregation. Therefore, an aggregation inhibitor targeting the VQIINK region in tau may be an effective therapeutic agent for AD. We have previously shown that the Fab domain (Fab2r3) of a tau antibody that recognizes the VQIINK sequence can inhibit tau aggregation, and we have determined the tertiary structure of the Fab2r3-VQIINK complex. In this report, we determined the tertiary structure of apo Fab2r3 and analyzed differences in the structures of apo Fab2r3 and Fab2r3-VQIINK to examine the ligand recognition mechanism of Fab2r3. In comparison with the Fab2r3-VQIINK structure, there were large differences in the arrangement of the constant and variable domains in apo Fab2r3. Remarkable structural changes were especially observed in the H3 and L3 loop regions of the complementarity determining regions (CDRs) in apo Fab2r3 and the Fab2r3-VQIINK complex. These structural differences in CDRs suggest that formation of hydrophobic pockets suitable for the antigen is important for antigen recognition by tau antibodies.

Usefulness of Magnifying Endoscopy with Narrow-Band Imaging for Diagnosing Mixed Poorly Differentiated Gastric Cancers.

INTRODUCTION: Curative rates of endoscopic treatment for undifferentiated-type early gastric cancer (EGC), particularly mixed poorly differentiated adenocarcinoma (MIXED-POR), are lower than those of endoscopic treatment for the differentiated type. Magnifying endoscopy with narrow-band imaging (ME-NBI) is useful for diagnoses of the histological type. This study aimed to investigate the detection rates of MIXED-POR among undifferentiated-type EGCs using biopsy and ME-NBI in order to improve curative rates through endoscopic treatment. METHODS: We analyzed 267 lesions initially subjected to endoscopic submucosal resection (ESD) and histologically diagnosed as undifferentiated-type EGCs between July 2005 and December 2016 at our hospital. We obtained written informed consent from all participants. Biopsy and ME-NBI findings were compared to distinguish pure signet ring cell carcinoma (PURE-SIG) and MIXED-POR. ME-NBI findings were divided into 2 categories depending on the presence of irregular vessels. Results of biopsy and ME-NBI (combination method) were also analyzed, and detection rates of MIXED-POR and PURE-SIG were evaluated in terms of sensitivity, specificity, and accuracy. RESULTS: Overall, 114 lesions were analyzed. Fifty-eight lesions (50.9%) were identified as MIXED-POR. With biopsy, the detection rate of MIXED-POR was significantly lower than that of PURE-SIG (p < 0.0001). ME-NBI detected significantly more MIXED-POR with irregular vessels than PURE-SIG (p < 0.0001). The combination method could detect significantly more MIXED-POR than PURE-SIG (p < 0.0001). The sensitivity and accuracy for MIXED-POR diagnosis were significantly higher with the combination method than with biopsy alone (p < 0.0001). DISCUSSION/CONCLUSION: Combining biopsy and ME-NBI improved the accuracy of pretreatment diagnosis before ESD in undifferentiated-type cancer.

Additional Treatment Following Noncurative Endoscopic Resection for Esophageal Squamous Cell Carcinoma: A Comparison of Outcomes between Esophagectomy and Chemoradiotherapy.

BACKGROUND: Endoscopic resection (ER) has been widely implemented for cT1N0 esophageal squamous cell carcinoma (ESCC). Additional therapy, including esophagectomy and chemoradiotherapy (CRT), is sometimes required after noncurative ER. METHODS: We retrospectively reviewed 108 patients who received any additional treatment following noncurative ER (positive vertical margins, lymphovascular invasion, or invasion depth of submucosa or more), and compared the short- and long-term outcomes between the two treatment modalities. RESULTS: Of 108 patients, 56 underwent esophagectomy (E group), and 52 received CRT (CRT group). A positive vertical margin was observed in 17 (14.8%) patients and high risks of occult lymph node metastasis were observed in 91 (85.2%) patients, as well as lymphovascular invasion in 35 (32.4%) patients, invasion depth of the submucosa or more in 27 (25.0%) patients, and both in 29 (26.9%) patients. The E group patients were significantly younger (p = 0.046) and tended to present with larger tumors than those in the CRT group (p = 0.057). Lymphatic invasion was more frequent in the E group (p = 0.019), and, furthermore, one treatment-related death was observed in the E group. There were no significant differences between the groups in overall and disease-specific survival (p = 0.406 and 0.151, respectively), however, recurrence was only observed in the CRT group. CONCLUSION: Both esophagectomy and CRT are safe and effective as additional treatments after noncurative ER in patients with ESCC. Esophagectomy is oncologically safe, whereas a risk of postoperative morbidity and mortality remains. Although the adverse events are acceptable, CRT has a certain degree of risk of disease recurrence.

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.

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.

Ability of artificial intelligence to detect T1 esophageal squamous cell carcinoma from endoscopic videos and the effects of real-time assistance.

Diagnosis using artificial intelligence (AI) with deep learning could be useful in endoscopic examinations. We investigated the ability of AI to detect superficial esophageal squamous cell carcinoma (ESCC) from esophagogastroduodenoscopy (EGD) videos. We retrospectively collected 8428 EGD images of esophageal cancer to develop a convolutional neural network through deep learning. We evaluated the detection accuracy of the AI diagnosing system compared with that of 18 endoscopists. We used 144 EGD videos for the two validation sets. First, we used 64 EGD observation videos of ESCCs using both white light imaging (WLI) and narrow-band imaging (NBI). We then evaluated the system using 80 EGD videos from 40 patients (20 with superficial ESCC and 20 with non-ESCC). In the first set, the AI system correctly diagnosed 100% ESCCs. In the second set, it correctly detected 85% (17/20) ESCCs. Of these, 75% (15/20) and 55% (11/22) were detected by WLI and NBI, respectively, and the positive predictive value was 36.7%. The endoscopists correctly detected 45% (25-70%) ESCCs. With AI real-time assistance, the sensitivities of the endoscopists were significantly improved without AI assistance (p < 0.05). AI can detect superficial ESCCs from EGD videos with high sensitivity and the sensitivity of the endoscopist was improved with AI real-time support.

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.

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.

Diagnostic yield of conventional endoscopy with endoscopic ultrasonography for submucosal invasion of superficial esophageal squamous cell carcinoma: a post hoc analysis of multicenter prospective confirmatory study (JCOG0508).

BACKGROUND: Endoscopic ultrasonography (EUS) is reportedly the reliable modality to predict the depth of esophageal squamous cell carcinoma (ESCC), however, most previous studies are retrospective or single-centered. We aimed to evaluate the diagnostic ability of conventional endoscopy and EUS using the data from a multicenter prospective study of endoscopic resection (ER) followed by chemoradiotherapy for cSM1-2N0M0 ESCC (JCOG0508). METHODS: All lesions were evaluated as cSM cancer with both conventional endoscopy and EUS before enrollment and judged as cSM1 or cSM2 in real time. We compared the clinical and pathological diagnoses for tumor depth and assessed the positive predictive value (PPV) for pSM (pSM/cSM) as the primary endpoint. We also investigated the clinical factors affecting the pathological depth of SM. RESULTS: 175 lesions were examined, and clinical diagnosis was SM1 in 114 and SM2 in 61 lesions. The pathological diagnoses of the epithelium, lamina propria mucosa, muscularis mucosae, SM1, and SM2 were 3, 31, 55, 17, and 69. The PPV for pSM was 49.1% (86/175) in all lesions, 34.2% (39/114) in cSM1 lesions, and 77.0% (47/61) in cSM2 lesions. Multivariable analysis demonstrated that cSM2 (vs. cSM1, OR 6.79) was an independent clinical factor associated with pSM. CONCLUSIONS: While the accurate depth diagnosis in cSM ESCC was difficult to make, the clinical diagnosis of SM2 with both conventional endoscopy and EUS was significantly associated with pSM. Furthermore, diagnostic ER could be recommended to confirm the pathological diagnosis especially in cSM1 lesions with both conventional endoscopy and EUS.

Detecting early gastric cancer: Comparison between the diagnostic ability of convolutional neural networks and endoscopists.

OBJECTIVES: Detecting early gastric cancer is difficult, and it may even be overlooked by experienced endoscopists. Recently, artificial intelligence based on deep learning through convolutional neural networks (CNNs) has enabled significant advancements in the field of gastroenterology. However, it remains unclear whether a CNN can outperform endoscopists. In this study, we evaluated whether the performance of a CNN in detecting early gastric cancer is better than that of endoscopists. METHODS: The CNN was constructed using 13,584 endoscopic images from 2639 lesions of gastric cancer. Subsequently, its diagnostic ability was compared to that of 67 endoscopists using an independent test dataset (2940 images from 140 cases). RESULTS: The average diagnostic time for analyzing 2940 test endoscopic images by the CNN and endoscopists were 45.5 ± 1.8 s and 173.0 ± 66.0 min, respectively. The sensitivity, specificity, and positive and negative predictive values for the CNN were 58.4%, 87.3%, 26.0%, and 96.5%, respectively. These values for the 67 endoscopists were 31.9%, 97.2%, 46.2%, and 94.9%, respectively. The CNN had a significantly higher sensitivity than the endoscopists (by 26.5%; 95% confidence interval, 14.9-32.5%). CONCLUSION: The CNN detected more early gastric cancer cases in a shorter time than the endoscopists. The CNN needs further training to achieve higher diagnostic accuracy. However, a diagnostic support tool for gastric cancer using a CNN will be realized in the near future.

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.