Precise highlighting of the pancreas by semantic segmentation during robot-assisted gastrectomy: visual assistance with artificial intelligence for surgeons.

BACKGROUND: A postoperative pancreatic fistula (POPF) is a critical complication of radical gastrectomy for gastric cancer, mainly because surgeons occasionally misrecognize the pancreas and fat during lymphadenectomy. Therefore, this study aimed to develop an artificial intelligence (AI) system capable of identifying and highlighting the pancreas during robot-assisted gastrectomy. METHODS: A pancreas recognition algorithm was developed using HRNet, with 926 training images and 232 validation images extracted from 62 scenes of robot-assisted gastrectomy videos. During quantitative evaluation, the precision, recall, intersection over union (IoU), and Dice coefficients were calculated based on the surgeons' ground truth and the AI-inferred image from 80 test images. During the qualitative evaluation, 10 surgeons answered two questions related to sensitivity and similarity for assessing clinical usefulness. RESULTS: The precision, recall, IoU, and Dice coefficients were 0.70, 0.59, 0.46, and 0.61, respectively. Regarding sensitivity, the average score for pancreas recognition by AI was 4.18 out of 5 points (1 = lowest recognition [less than 50%]; 5 = highest recognition [more than 90%]). Regarding similarity, only 54% of the AI-inferred images were correctly differentiated from the ground truth. CONCLUSIONS: Our surgical AI system precisely highlighted the pancreas during robot-assisted gastrectomy at a level that was convincing to surgeons. This technology may prevent misrecognition of the pancreas by surgeons, thus leading to fewer POPFs.

Pterostilbene Induces Apoptosis from Endoplasmic Reticulum Stress Synergistically with Anticancer Drugs That Deposit Iron in Mitochondria.

Anticancer agents are playing an increasing role in the treatment of gastric cancer (GC); however, novel anticancer agents have not been fully developed. Therefore, it is important to investigate compounds that improve sensitivity to the existing anticancer drugs. We have reported that pterostilbene (PTE), a plant stilbene, enhances the antitumor effect of low doses of sunitinib in gastric cancer cells accumulating mitochondrial iron (II) (mtFe) at low doses. In this study, we investigated the relationship between the mtFe deposition and the synergistic effect of PTE and different anticancer drugs. For this study, we used 5-fluorouracil (5FU), cisplatin (CPPD), and lapatinib (LAP), which are frequently used in the treatment of GC, and doxorubicin (DOX), which is known to deposit mtFe. A combination of low-dose PTE and these drugs suppressed the expression of PDZ domain-containing 8 (PDZD8) and increased mtFe accumulation and mitochondrial H2O2. Consequently, reactive oxygen species-associated hypoxia inducible factor-1α activation induced endoplasmic reticulum stress and led to apoptosis, but not ferroptosis. In contrast, 5FU and CDDP did not show the same changes as those observed with PTE and DOX or LAP, and there was no synergistic effect with PTE. These results indicate that the combination of PTE with iron-accumulating anticancer drugs exhibits a strong synergistic effect. These findings would help in developing novel therapeutic strategies for GC. However, further clinical investigations are required.

Proposal for T3 classification of esophagogastric junction carcinoma based on the interconnection of extramural anatomical structures.

Classification of extramural invasion of esophagogastric junction carcinoma (EGJC) is not yet established. The anatomy surrounding the EGJ alters between the mediastinum and the abdominal cavity. This review proposed a T3 classification of EGJC based on anatomical continuity. Analysis of endoscopic ultrasound images, review of intraoperative images, and detailed observation of surgical specimens were followed by a review of the literature. In the EGJ, the muscularis propria of the esophagus is enclosed in mediastinal adipose tissue called the adventitia, which is surrounded by the diaphragmatic crus and contains the paraesophageal lymph nodes (LNs). After passing through the esophageal hiatus along with the vagus nerves and blood vessels, the adventitia joins the adipose tissue containing the paracardial LNs, which is covered by the peritoneum, and then further divides into the lesser and greater omentum. The connective tissue outside the muscularis propria of the stomach, including the adipose tissue of the omentum, is called the subserosa. According to the TNM classification, T3 esophageal and gastric cancer is defined as invasion of the adventitia and subserosa, respectively. Given that the adventitia is anatomically continuous with the subserosa, T3 tumors of the EGJ can be described as those that extend through the muscularis propria but do not invade the peritoneum or diaphragmatic crus. We propose classifying T3 EGJC as "tumor extends through muscularis propria" rather than using the separate terms "adventitia" and "submucosa". T4 could be "tumor perforates serosa or invades adjacent structures", as per the current gastric cancer classification.

5-Aminolevulinic acid overcomes hypoxia-induced radiation resistance by enhancing mitochondrial reactive oxygen species production in prostate cancer cells.

BACKGROUND: The naturally occurring amino acid 5-aminolevulinic acid (5-ALA) is a precursor of protoporphyrin IX (PpIX) biosynthesised in the mitochondria. When accumulated PpIX is excited by light (wavelength of 625-635 nm), reactive oxygen species (ROS) are generated. Here, we investigated whether 5-ALA may increase the sensitisation of prostate cancer (PCA) cells to radiotherapy through the generation of ROS via its metabolite, PpIX. METHODS: Effect of 5-ALA on PC-3 and DU-145 PCA cell lines treated with ionising radiation (IR) was examined in vitro and in vivo with assessment by clonogenic assay, mitochondrial function and ROS production under normoxia or hypoxia condition. RESULTS: 5-ALA enhanced intra-mitochondrial ROS production immediately after exposure to IR and decreased mitochondrial membrane potential via increase of intra-cellular PpIX. IR with 5-ALA induced mitochondrial dysfunction and increased ATP production, switching energy metabolism to the quiescence. Under hypoxic condition, ROS burst and mitochondrial dysfunction were induced by IR with 5-ALA resulting reducing cancer stemness and radiation resistance. CONCLUSION: These results suggest that combined therapy with 5-ALA and radiation therapy is a novel strategy to improve the anti-cancer effects of radiation therapy for PCA.

Marked improvement of severe reflux esophagitis following proximal gastrectomy with esophagogastrostomy by the right gastroepiploic vessels-preserving antrectomy and Roux-en-Y biliary diversion.

Duodenogastroesophageal reflux (DGER) following esophagectomy or gastrectomy can cause severe esophagitis, which impairs patients' quality of life and increases the risk of esophageal carcinogenesis. It is sometimes resistant to medical treatment, and surgical treatment is considered effective in such cases. However, an optimal operative procedure for medical treatment-resistant reflux esophagitis (RE) after proximal gastrectomy (PG) with esophagogastrostomy (EG) has not yet been established. We performed the right gastroepiploic vessels-preserving antrectomy and Roux-en-Y biliary diversion in a 70-year-old man with medical treatment-resistant severe esophagitis caused by DGER following PG with EG for esophagogastric junction cancer. The postoperative course was uneventful, and esophagogastroduodenoscopy performed on the 19th postoperative day showed marked improvement in the esophageal erosions. The patient reported symptomatic relief. The right gastroepiploic vessels-preserving antrectomy and Roux-en-Y biliary diversion were considered safe and feasible for medical treatment-resistant RE following PG with EG.

History of the lymph node numbering system in the Japanese Classification of Gastric Carcinoma since 1962.

The Japanese Classification of Gastric Carcinoma was established by the Japanese Research Society for Gastric Cancer in 1962. The latest 15th edition was published in 2017. One of its main features is that lymph nodes are numbered as stations. The number of groups has increased from 16 to 36 in 55 years. Seven groups (nos. 1, 2, 5, 7, 9, 10, and 15) were retained from the original classification. Nine groups (nos. 3, 4, 6, 8, 11, 12, 13, 14, and 16) were sub-divided into two or more groups. Furthermore, seven groups (nos. 17, 18, 19, 20, 110, 111, and 112) were added in the 6th, 11th, and 12th editions. This numbering system helps surgeons recognize the exact lymph nodes that need to be dissected. However, the numbering system has become extremely complicated. It is necessary to organize the historical background of each lymph node station and share the definitions clearly. This review focuses on nine anatomical zones around the stomach and summarizes the history of lymph node stations in the Japanese Classification of Gastric Carcinoma. Lymph node stations will continue to be modified in the future, and the historical background may be useful in future revisions.

Sunitinib and Pterostilbene Combination Treatment Exerts Antitumor Effects in Gastric Cancer via Suppression of PDZD8.

The use of molecular-targeted drugs in the treatment of gastric cancer is increasing. However, the variety of molecular-targeted drugs in gastric cancer is still limited, and the development of new molecular-targeted therapies is required. The effect of combining sunitinib (SUN) with pterostilbene (PTE) on the human gastric cancer cell lines TMK1 and MKN74 was examined in in vitro and in vivo. Compared with SUN or PTE treatment alone, cotreatment induced pronounced suppression of cell proliferation, with a marked increase in oxidative stress. SUN was associated with a significant retention of mitochondrial Fe2+. SUN-treated cells decreased expression of PDZ domain-containing protein 8 (PDZD8). Knockdown of PDZD8 in both cells induced Fe2+ retention, and siPDZD8+PTE markedly suppressed cell proliferation with suppressed oxidative phosphorylation, as did the combination of SUN+PTE. In a nude mouse tumor model, a pronounced antitumor effect was observed with SUN+PTE treatment compared to SUN alone. PDZD8 may be a newly discovered off-target for SUN, and that the combined use of PTE with SUN significantly promotes antitumor activity in gastric cancer cell lines. The combined use of SUN and PTE might be a new molecular-targeted therapy for gastric cancer.

Anastomosis behind the sternoclavicular joint is associated with increased incidence of anastomotic stenosis in retrosternal reconstruction with a gastric conduit after esophagectomy.

Anastomotic stenosis after esophagectomy is a major cause of long-term morbidity because it leads to poor dietary intake and malnutrition that markedly reduces the quality of life. The aim of this study was to test the hypothesis that anastomosis behind the sternoclavicular (SC) joint in retrosternal reconstruction is associated with an increased risk of anastomotic stenosis compared with anastomosis deviated from the joint. Among 226 patients who underwent esophagectomy for esophageal cancer between April 2010 and March 2019, we selected 114 patients who underwent retrosternal reconstruction using a gastric conduit for this study. They were classified into two groups according to the location of the anastomosis as determined by axial sections on postoperative computed tomography scans: anastomosis located behind the SC joint (Group B; n = 71) and anastomosis deviated from the joint (Group D; n = 43). The primary endpoint was the difference in the incidence of anastomotic stenosis between the two groups. Whether the occurrence of anastomotic leak affected the likelihood of anastomotic stenosis was also investigated. The incidence of anastomotic stenosis was significantly higher in Group B than in Group D (71.8% [n = 51] vs. 18.6% [n = 8]; P < 0.0001). The incidence of stenosis in patients who developed an anastomotic leak was significantly higher in Group B than in Group D (88.0% vs. 41.7%; P = 0.0057), although the findings were similar in patients who did not develop anastomotic leak (63.0% and 9.7%, respectively; P < 0.0001). We conclude that anastomosis located behind the SC joint in retrosternal reconstruction with a gastric conduit after esophagectomy is associated with an increased risk of anastomotic stenosis regardless of the development of anastomotic leak.

BRAF Mutation Is Associated with Hyperplastic Polyp-Associated Gastric Cancer.

Gastric hyperplastic polyps (GHP) are frequently found to be benign polyps and have been considered to have a low carcinogenic potential. The characteristics of the hyperplastic polyp-associated gastric cancer (HPAGC) remain unclear. Therefore, we analyzed samples from 102 GHP patients and identified 20 low-grade atypical GHPs (19.6%), 7 high-grade atypical GHPs (6.9%), and 5 intramucosal cancer samples (4.9%). GHP atypia was more common in the elderly and increased with increasing polyp size. In particular, polyps larger than 1 cm were associated with a higher grade and cancer. Furthermore, mucus production decreased with increasing atypia. Although no correlation was found between atypia and Helicobacter pylori infection or intestinal metaplasia, enhanced proliferative ability (Ki-67) did correlate with atypia, as did nuclear 8-hydroxy-2'-deoxyguanosine levels. Interestingly, 4-hydroxynonenal levels in granulation tissue and the area ratio of granulation tissue within polyps also correlated with GHP atypia. In five cases of HPAGC, three cases exhibited caudal type homeobox transcription factor (CDX2)-positive cells and a mixed mucin phenotype, which is considered to be related to H. pylori infection. By contrast, two cases were CDX2 negative, with a gastric mucin phenotype, and H. pylori infection was not observed in the tumor or the surrounding mucosa. In these cases, a v-raf murine sarcoma viral oncogene homolog B1 (BRAF) mutation (V600E) was detected. All cancer samples showed high stemness and p53 protein accumulation, but no KRAS mutations. The molecular and phenotypic characteristics of the cases characterized by BRAF mutations may represent a novel subtype of HPAGC, reflecting a conserved pathway to oncogenesis that does not involve H. pylori infection. These findings are worthy of further investigation in a large-scale study with a substantial cohort of HPAGC patients to establish their clinical significance.

Effect of Proton Pump Inhibitors on Colorectal Cancer.

Proton pump inhibitors (PPIs) are administered commonly to aged people; however, their effect on colorectal cancer (CRC) has still not been fully elucidated. Here, we examined the effect of PPIs and consequent alkalization on CRC cells. PPI administration alkalized the fecal pH and increased serum gastrin concentration. PPI and pH8 treatment (alkalization) of CMT93 mouse colon cancer cells inhibited cell growth and invasion, increased oxidative stress and apoptosis, and decreased mitochondrial volume and protein levels of cyclin D1 and phosphorylated extracellular signal-regulated kinase (pERK) 1/2. In contrast, gastrin treatment enhanced growth and invasion, decreased oxidative stress and apoptosis, and increased mitochondrial volume and cyclin D1 and pERK1/2 levels. Concurrent treatment with a PPI, pH8, and gastrin increased aldehyde dehydrogenase activity and also enhanced liver metastasis in the BALB/c strain of mice. PPI administration was associated with Clostridium perfringens enterotoxin (CPE) in CRC lesions. CPE treatment activated yes-associated protein (YAP) signals to enhance proliferation and stemness. The orthotopic colon cancer model of CMT93 cells with long-term PPI administration showed enhanced tumor growth and liver metastasis due to gastrin and YAP activation, as indicated by gastrin receptor knockdown and treatment with a YAP inhibitor. These findings suggest that PPI promotes CRC growth and metastasis by increasing gastrin concentration and YAP activation, resulting in gut flora alteration and fecal alkalization. These findings suggest that PPI use in colorectal cancer patients might create a risk of cancer promotion.

Treatment strategy for successful conversion surgery in clinical stage IVB gastric cancer.

INTRODUCTION: Recent advances in chemotherapy have resulted in successful conversion surgery (CS) for clinical stage (cStage) IVB gastric cancer (GC). This study aimed to evaluate the success rate of CS in clinical practice and determine optimal treatment strategies. METHODS: Totally, 166 patients with cStage IVB gastric and gastroesophageal junction adenocarcinoma, who underwent chemotherapy at Hyogo Medical University Hospital between January 2017 and June 2022, were included. CS was performed after confirming tumor to be M0 based on imaging and/or staging laparoscopy, except for resectable liver metastases. Preoperative chemotherapy was continued for at least 6 months provided that adverse events were manageable. RESULTS: Of 125 eligible patients, 23 were treated with CS, achieving a conversion rate of 18.4% and an R0 resection rate of 91.3%. The median duration of preoperative chemotherapy was 8.5 months; the median number of cycles was eight. The highest conversion rate was observed in patients receiving first-line treatment (14.4%), followed by those receiving second and third lines (5.8% and 2.3%, respectively). The median survival time in patients who received CS was significantly longer than that in patients who continued chemotherapy alone (56.7 versus 16 months, respectively, P < 0.0001). There was no significant difference in the 3-year overall survival between the patients who achieved CS after first-line treatment (63.2%, n = 18) and those who achieved CS after second- or third-line treatment (66.7%, n = 5). CONCLUSION: Consistent chemotherapy strategies could lead to successful CS and improved prognosis in a greater number of patients with cStage IVB GC, regardless of line of treatment.

Potential advantages of robotic total gastrectomy for gastric cancer: a retrospective comparative cohort study.

Laparoscopic total gastrectomy (LTG) is a highly technical surgery that can lead to postoperative complications. Whether the recently introduced robotic surgery overcomes the drawbacks of laparoscopic surgery in total gastrectomy remains controversial. Therefore, we aimed to elucidate the potential benefits of robotic total gastrectomy (RTG) and compare the short-term outcomes of RTG and LTG. We retrospectively analyzed 56 patients with primary gastric or esophagogastric junction cancer who underwent RTG or LTG between June 2017 and July 2021. The groups were compared in terms of operative outcomes and postoperative complications. Potential risk factors associated with postoperative complications were assessed by performing multivariable analysis using logistic regression models via the exact method. Operation time was significantly longer, and postoperative hospital stay was significantly shorter in the robotic group (550 vs. 466 min, P < 0.001; 13 vs. 18 days, P = 0.013, respectively). The incidence of overall postoperative complications of Clavien-Dindo grade ≥ II was 18.5% and 24.1% in the RTG and LTG groups, respectively. Pancreatic fistulas were not observed, but other local complications were observed in 0% and 17.2% of the RTG and LTG groups, respectively (P = 0.052). In the multivariable analysis, the independent risk factors for local complications were laparoscopic surgery (odds ratio [95% confidence interval] 8.542 [1.065-∞], P = 0.045) and esophagogastric junction cancer (16.646 [2.559-∞], P = 0.005). Compared with LTG, RTG was associated with fewer local complications (mainly anastomotic leakage), especially in cases of esophagogastric junction cancer with high anastomotic sites.

Anastomotic leakage after esophagectomy possibly caused by compression of the gastric conduit behind the sternoclavicular joint: a report of three cases.

BACKGROUND: The narrowness of the thoracic inlet is often a problem in retrosternal reconstruction after esophagectomy. We report here three cases in which compression of the gastric conduit behind the sternoclavicular joint possibly caused anastomotic leakage. CASE PRESENTATIONS: The first case was a 71-year-old man who underwent subtotal esophagectomy for upper esophageal cancer followed by retrosternal reconstruction. On postoperative day 2, he developed septic shock and underwent reoperation because of a necrotic gastric conduit. The tip of the conduit above the manubrium was necrotic due to strangulation as a result of compression by the sternoclavicular joint. The second and third cases were a 50-year-old woman and a 71-year-old man who underwent subtotal esophagectomy for middle and lower esophageal cancer, respectively, followed by retrosternal reconstruction. Despite indocyanine green fluorescence imaging indicating adequate blood flow in both cases, the tip of the conduit appeared pale and congested because of compression by the sternoclavicular joint after anastomosis. Postoperatively, these two patients developed anastomotic leakage that was confirmed endoscopically on the ventral side of the gastric wall that had been pale intraoperatively. CONCLUSIONS: When performing reconstruction using the retrosternal route after esophagectomy, it is important to ensure that compression by the sternoclavicular joint does not have an adverse impact on blood flow at the tip of the gastric conduit.

Robot-assisted Valvuloplastic Esophagogastrostomy by Double-flap Technique Using a Knifeless Linear Stapler After Proximal Gastrectomy.

After proximal gastrectomy, valvuloplastic esophagogastrostomy by double-flap technique could be the ideal reconstruction to prevent gastroesophageal reflux. However, it is demanding procedure in laparoscopic surgery. In this video, we demonstrate a robot-assisted double-flap technique using a knifeless stapler.

Successful revision surgery for very late-onset stomal obstruction following Gomez gastroplasty: a case report.

BACKGROUND: Gomez gastroplasty, which was developed in the 1970s as one of the gastric restrictive surgeries for severe obesity, partitions the stomach using a stapler from the lesser towards the greater curvature at the upper gastric body, leaving a small channel. This procedure is no longer performed due to poor outcomes, but surgeons can encounter late-onset complications even decades after the surgery. Here, we report a case of very late-onset stomal obstruction following Gomez gastroplasty which was successfully treated by revision surgery. CASE PRESENTATION: A 58-year-old man was referred to our institution with sudden-onset nausea and vomiting. He underwent weight loss surgery in the USA in 1979, but the details of the surgery were unclear. Esophagogastroduodenoscopy demonstrated a stoma at the greater curvature of the upper gastric body, and fluoroscopy showed retention of contrast medium in the fundus and poor outflow through the stoma. Abdominal computed tomography revealed a staple line partitioning the stomach. Considering these preoperative investigation findings and the period during which the surgery was performed, the patient was diagnosed with very late-onset stomal obstruction following Gomez gastroplasty. Supporting the preoperative diagnosis, the surgical findings revealed a staple line extending from the lesser towards the greater curvature of the upper gastric body and a channel reinforced by a running seromuscular suture on the greater curvature. Moreover, gastric torsion caused by the enlarged proximal gastric pouch was found. Re-gastroplasty involving wedge resection of the original channel was performed followed by construction of a new channel. Postoperative course was uneventful, and the patient no longer had symptoms of stomal obstruction after revision surgery. CONCLUSIONS: Re-gastroplasty was safe and feasible for very late-onset stomal obstruction following Gomez gastroplasty. Accurate preoperative diagnosis based on the patient's interview and the investigation findings was important for surgical planning. A careful follow-up is required to prevent excessive weight regain after revision surgery.

Pathological Complete Response and Successful Conversion Surgery After Nivolumab Therapy for Stage IV Oesophagogastric Junction Cancer.

BACKGROUND: Multimodality treatment including immune check point inhibitors is required for stage IV oesophagogastric junction cancer (OGJC). CASE REPORT: A 69-year-old man, was diagnosed with advanced OGJC and para-aortic lymph node metastasis (T3N+M1, stage IV), which upon biopsy, was shown to be an adenocarcinoma. After eight courses of nivolumab as third-line chemotherapy, the primary tumour and enlarged regional and para-aortic lymph nodes shrunk markedly, while tumour markers decreased within normal ranges. We performed a minimally invasive Ivor-Lewis oesophagectomy with completion of an abdominal D2 and transhiatal lower mediastinal lymph node dissection. Pathological findings revealed a complete response for the primary tumour and a regional lymph node metastasis. A biopsy of the previous sample revealed microsatellite instability-negativity, Epstein-Barr virus-negativity, and programmed cell death-1-ligand combined positive score of 2. He was followed up for 3 months without recurrence. CONCLUSION: Nivolumab may induce pathological complete response for stage IV OGJC even in cases negative for microsatellite instability and Epstein-Barr virus, besides the programmed cell death-1-ligand combined positive score of <5.

A minute primary gastric synovial sarcoma with ulcer: a case report.

BACKGROUND: Synovial sarcomas are a rare type of high-grade sarcomas with unknown cell origin. They arise predominantly in the soft tissues but rarely in the stomach. We recently encountered a rare case of minute gastric synovial sarcoma. CASE PRESENTATION: A 61-year-old Japanese woman was pointed out edematous erosion at the body of the stomach. Biopsy specimen showed dense proliferation of spindle-shaped tumor cells mixed with smooth muscle fibers of the muscularis mucosae. Although the definite histological diagnosis was undetermined, the patient underwent laparoscopic wedge resection of the stomach. Histological examination of the resected sample revealed that the maximum diameter of the tumor was only 6 mm and that dense proliferation of rather uniform spindle tumor cells were observed mainly in the submucosa. Immunohistochemistry showed that they were positive for pan-keratin, CD99 and TLE1. SS18-SSX fusion-specific antibody gave diffuse positive staining to the tumor cells, and analysis using mRNA extracted from paraffin sections revealed that the tumor had SS18-SSX1 fusion gene. Thus, it was diagnosed as gastric synovial sarcoma, monophasic fibrous type. CONCLUSIONS: Primary synovial sarcoma of the stomach is rare and only 47 cases have been reported in the English literature to date. The maximum diameter of the lesion of our case was 6 mm which is the smallest among them.

Accuracy of Preoperative Endoscopy in Determining Tumor Location Required for Surgical Planning for Esophagogastric Junction Cancer.

PURPOSE: The surgical strategy for esophagogastric junction (EGJ) cancer depends on the tumor location as measured relative to the EGJ line. The purpose of this study was to clarify the accuracy of diagnostic endoscopy in different clinicopathological backgrounds. METHODS: Subjects were 74 consecutive patients with abdominal esophagus to upper gastric cancer who underwent surgical resection. Image-enhanced endoscopy with narrow-band imaging (NBI) was used to determine the EGJ line, prioritizing the presence of palisade vessels, followed by the upper end of gastric folds, as a landmark. The relative positional relationship between the tumor epicenter and the EGJ line was classified into six categories, and the agreement between endoscopic and pathologic diagnoses was examined to evaluate prediction accuracy. RESULTS: The concordance rate of 69 eligible cases was 87% with a kappa coefficient (K) of 0.81. The palisade vessels were observed in 62/69 patients (89.9%). Of the 37 pathological EGJ cancers centered within 2 cm above and below the EGJ line, Barrett's esophagus was found to be a significant risk factor for discordance (risk ratio, 4.40; p = 0.042); the concordance rate of 60% (K = 0.50) in the Barrett's esophagus group was lower than the rate of 91% (K = 0.84) in the non-Barrett's esophagus group. In five of six discordant cases, the EGJ line was estimated to be proximal to the actual line. CONCLUSION: Diagnostic endoscopy is beneficial for estimating the location of EGJ cancer, with a risk of underestimating esophageal invasion length in patients with Barrett's esophagus.

Pathological Complete Remission of Liver Metastases Correlates With Elimination of Tumor-infiltrating Tregs in Gastric Cancer.

BACKGROUND/AIM: Tumor-infiltrating Foxp3+ regulatory T-cells (Ti-Tregs) promote tumor progression and contribute to poor prognosis in gastric cancer, but the relationship between Ti-Tregs and response to chemotherapy for liver metastases from gastric cancer (LMGC) is unclear. We estimated the correlation between pathological response to chemotherapy and Ti-Tregs in LMGC. PATIENTS AND METHODS: Ti-Tregs were analyzed with immunohistochemistry as CD3+ Foxp3+ cells in patients with synchronous LMGC. RESULTS: Of 53 patients with LMGC, 49 received chemotherapy as initial treatment and 10 underwent R0 resection. LMGC disappeared pathologically in 5 resected cases despite radiologically residual disease. Ti-Tregs were found frequently in residual LMGC and primary lesions but rarely in tumor scar tissue. There was no relationship between frequency of CD8+ cells and pathological response. CONCLUSION: Marked reduction in Ti-Tregs correlates with pathological complete remission of LMGC. Ti-Tregs may be a biomarker to predict the effects of chemotherapy when used in combination with radiological findings.

Automated segmentation by deep learning of loose connective tissue fibers to define safe dissection planes in robot-assisted gastrectomy.

The prediction of anatomical structures within the surgical field by artificial intelligence (AI) is expected to support surgeons' experience and cognitive skills. We aimed to develop a deep-learning model to automatically segment loose connective tissue fibers (LCTFs) that define a safe dissection plane. The annotation was performed on video frames capturing a robot-assisted gastrectomy performed by trained surgeons. A deep-learning model based on U-net was developed to output segmentation results. Twenty randomly sampled frames were provided to evaluate model performance by comparing Recall and F1/Dice scores with a ground truth and with a two-item questionnaire on sensitivity and misrecognition that was completed by 20 surgeons. The model produced high Recall scores (mean 0.606, maximum 0.861). Mean F1/Dice scores reached 0.549 (range 0.335-0.691), showing acceptable spatial overlap of the objects. Surgeon evaluators gave a mean sensitivity score of 3.52 (with 88.0% assigning the highest score of 4; range 2.45-3.95). The mean misrecognition score was a low 0.14 (range 0-0.7), indicating very few acknowledged over-detection failures. Thus, AI can be trained to predict fine, difficult-to-discern anatomical structures at a level convincing to expert surgeons. This technology may help reduce adverse events by determining safe dissection planes.