Automated artificial intelligence-based phase-recognition system for esophageal endoscopic submucosal dissection (with video)

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) for superficial esophageal cancer is a multistep treatment involving several endoscopic processes. Although analyzing each phase separately is worthwhile, it is not realistic in practice owing to the need for considerable manpower. To solve this problem, we aimed to establish a state-of-the-art artificial intelligence (AI)-based system, specifically, an automated phase-recognition system that can automatically identify each endoscopic phase based on video images.

METHODS

Ninety-four videos of ESD procedures for superficial esophageal cancer were evaluated in this single-center study. A deep neural network-based phase-recognition system was developed in an automated manner to recognize each of the endoscopic phases. The system was trained with the use of videos that were annotated and verified by 2 GI endoscopists.

RESULTS

The overall accuracy of the AI model for automated phase recognition was 90%, and the average precision, recall, and F value rates were 91%, 90%, and 90%, respectively. Two representative ESD videos predicted by the model indicated the usability of AI in clinical practice.

CONCLUSIONS

We demonstrated that an AI-based automated phase-recognition system for esophageal ESD can be established with high accuracy. To the best of our knowledge, this is the first report on automated recognition of ESD treatment phases. Because this system enabled a detailed analysis of phases, collecting large volumes of data in the future may help to identify quality indicators for treatment techniques and uncover unmet medical needs that necessitate the creation of new treatment methods and devices.

Identifying the Trends of Urinary microRNAs within Extracellular Vesicles for Esophageal Cancer

Background: The advancement of multidisciplinary treatment has increased the need to develop tests to monitor tumor burden during treatment. We herein analyzed urinary microRNAs within extracellular vesicles from patients with esophageal squamous cell carcinoma (ESCC) and normal individuals using a microarray. Methods: Patients with advanced ESCC who underwent esophagectomy (A), endoscopic submucosal resection (ESD) (B), and healthy donors (C) were included. Based on microRNA expression among the groups (Analysis 1), microRNAs with significant differences between groups A and C were selected (Analysis 2). Of these candidates, microRNAs in which the change between A and C was consistent with the change between B and C were selected for downstream analysis (Analysis 3). Finally, microRNA expression was validated in patients with recurrence from A (exploratory analysis). Results: For analysis 1, 205 microRNAs were selected. For Analyses 2 and 3, the changes in 18 microRNAs were consistent with changes in tumor burden as determined by clinical imaging and pathological findings. The AUC for the detection of ESCC using 18 microRNAs was 0.72. In exploratory analysis, three of eighteen microRNAs exhibited a concordant trend with recurrence. Conclusions: The current study identified the urinary microRNAs which were significantly expressed in ESCC patients. Validation study is warranted to evaluate whether these microRNAs could reflect tumor burden during multidisciplinary treatment for ESCC.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Clinical predictors of early postoperative recurrence after radical esophagectomy for thoracic esophageal cancer

PURPOSE

Esophagectomy for esophageal cancer has a high incidence rate of early postoperative recurrence and death. This study aimed to identify the clinical and pathological features in early recurrence cases and to confirm the usefulness of prediction using these factors for effective adjuvant therapy and postoperative surveillance.

METHODS

One hundred and twenty five patients who developed postoperative recurrence after undergoing radical esophagectomy for thoracic esophageal cancer were classified into two groups as follows: those with early recurrence at ≤ 6 months and those with nonearly recurrence at > 6 months after surgery. After identifying related factors of early recurrence, usefulness of these factors for prediction were examined in all patients with and without recurrence.

RESULTS

The analysis cohort consisted of 43 and 82 patients in the early and nonearly recurrence groups, respectively. In multivariate analysis, factors associated with early recurrence were higher initial levels of tumor markers (squamous cell carcinoma [SCC] ≥ 1.5 ng/ml in tumors, except for adenocarcinoma, and carcinoembryonic antigen [CEA] ≥ 5.0 ng/ml in adenocarcinoma) and higher venous invasion (v), i.e., ≥ 2 (p = 0.040 and p = 0.004, respectively). The usefulness of these two factors for recurrence prediction was confirmed in 378 patients, including 253 patients without recurrence. Patients with at least one of the two factors had significantly higher early recurrence rates than those without any factors in pStages II and III (odds ratio [OR], 6.333; p = 0016 and OR, 4.346; p = 0.008, respectively).

CONCLUSIONS

Early recurrence of thoracic esophageal cancer (i.e., during ≤ 6 months after esophagectomy) was associated with higher initial tumor marker levels and pathological findings of v ≥ 2. The combination of these two factors is useful as a simple and critical predictor of early postoperative recurrence.

The impact of thoracic duct resection on the long-term body composition of patients who underwent esophagectomy for esophageal cancer and survived without recurrence

BACKGROUND

We have reported the possible benefits of radical esophagectomy with thoracic duct (TD) resection in elective esophageal cancer surgery. However, the effect of TD resection on the long-term nutrition status remains unclear.

METHODS

Patients who underwent esophagectomy at Keio University between January 2006 and December 2018 were included, and those who had no recurrence for more than three years were evaluated. Changes in each body composition (muscle mass and body fat) were comparatively assessed between those who underwent TD resection or not, before and at, one, three and five years after surgery. Computed tomography images were analyzed on postoperative year 1, 3 and 5.

RESULTS

This study included 217 patients categorized in the TD-resected (TD-R) (156 patients) and TD-preserved (TD-P) (61 patients) groups. The loss of muscle mass was comparable between the groups. On the other hand, the loss of adipose tissues was significantly greater in the TD-R group than in the TD-P group at one and three years after surgery, while there was no statistical difference five years after surgery. Additionally, among patients with cT1N0M0 disease in whom survival advantage of TD resection has been reported previously, the loss of muscle mass did not differ between each group.

CONCLUSIONS

The change of muscle mass between the two groups was comparable. Although body fat mass was reduced by TD resection, it eventually recovered in the long term. In patients with esophageal cancer, TD resection may be acceptable without significant impact on body composition in the long term.

The Usability of Intensive Imaging Surveillance After Esophagectomy in Patients with Esophageal Cancer

BACKGROUND

Although imaging surveillance after esophagectomy is required to achieve long-term survival for patients with esophageal cancer, the optimal surveillance timing and interval remain unclear. This study was designed to investigate the differences in oncological outcomes based on the detection method for recurrence and surveillance interval in patients with recurrence detected by routine imaging examination after esophagectomy.

METHODS

A total of 527 patients who underwent thoracic esophagectomy for esophageal cancer with R0 resection between 2003 and 2021 in our department were enrolled in this study. Postoperative, routine surveillance was conducted at an outpatient clinic every 3 months, thoracoabdominal computed tomography (CT) every 4-6 months, and esophagogastroduodenoscopy every 6 months. The detection method and optimal interval of imaging surveillance also were investigated.

RESULTS

Of all patients, 161 patients developed recurrence during surveillance; 110 (68.3 %) by routine surveillance and 37 (23.0%) not detected by routine surveillance. Among patients who were diagnosed with recurrence following routine surveillance, patients with pStage IV disease on imaging surveillance by thoracoabdominal CT at an interval of ≤ 5 months had a better survival rate than those with an interval of 6 months (P = 0.004), whereas no significant difference among different intervals was observed in patients with pStage I-III disease.

CONCLUSIONS

Recurrence may have been detectable by our routine surveillance in approximately 70% of patients who developed recurrence. These findings demonstrate the necessity of different imaging surveillance intervals for different pStages of esophageal cancer.

The relationship between the esophageal endoscopic submucosal dissection technical difficulty and its intraoperative process

BACKGROUND

Estimating the esophageal endoscopic submucosal dissection (ESD) technical difficulty is important to reduce complications. Endoscopic duration is one of the related factors to a technical difficulty. The relationship between the esophageal ESD technical difficulty and its intraoperative process was analyzed as a first step toward automatic technical difficulty recognition using artificial intelligence.

METHODS

This study enrolled 75 patients with superficial esophageal cancer who underwent esophageal ESD. The technical difficulty score was established, which consisted of three factors, including total procedure duration, en bloc resection, and complications. Additionally, technical difficulty-related factors, which were perioperative factors that included the intraoperative process, were investigated.

RESULTS

Eight (11%) patients were allocated to high difficulty, whereas 67 patients (89%) were allocated to low difficulty. The intraoperative process, which was shown as the extension of each endoscopic phase, was significantly related to a technical difficulty. The area under the curve (AUC) values were higher at all the phase duration than at the clinical characteristics. Submucosal dissection phase (AUC 0.902; 95% confidence intervals (CI) 0.752-1.000), marking phase (AUC 0.827; 95% CI 0.703-0.951), and early phase which was defined as the duration from the start of marking to the end of submucosal injection (AUC 0.847; 95% CI 0.701-0.992) were significantly related to technical difficulty.

CONCLUSIONS

The intraoperative process, particularly early phase, was strongly associated with esophageal ESD technical difficulty. This study demonstrated the potential for automatic evaluation of esophageal ESD technical difficulty when combined with an AI-based automatic phase evaluation system.

Evaluation of Endoscopic Response Using Deep Neural Network in Esophageal Cancer Patients Who Received Neoadjuvant Chemotherapy

BACKGROUND

We previously reported that endoscopic response evaluation can preoperatively predict the prognosis and distribution of residual tumors after neoadjuvant chemotherapy (NAC). In this study, we developed artificial intelligence (AI)-guided endoscopic response evaluation using a deep neural network to discriminate endoscopic responders (ERs) in patients with esophageal squamous cell carcinoma (ESCC) after NAC.

METHOD

Surgically resectable ESCC patients who underwent esophagectomy following NAC were retrospectively analyzed in this study. Endoscopic images of the tumors were analyzed using a deep neural network. The model was validated with a test data set using 10 newly collected ERs and 10 newly collected non-ER images. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the endoscopic response evaluation by AI and endoscopists were calculated and compared.

RESULTS

Of 193 patients, 40 (21%) were diagnosed as ERs. The median sensitivity, specificity, PPV, and NPV values for ER detection in 10 models were 60%, 100%, 100%, and 71%, respectively. Similarly, the median values by the endoscopist were 80%, 80%, 81%, and 81%, respectively.

CONCLUSION

This proof-of-concept study using a deep learning algorithm demonstrated that the constructed AI-guided endoscopic response evaluation after NAC could identify ER with high specificity and PPV. It would appropriately guide an individualized treatment strategy that includes an organ preservation approach in ESCC patients.

Long-term variation in psoas muscle mass index is affected by short-term loss after esophagectomy in survivors of esophageal cancer

Changes in muscle mass may be an objective approach toward measuring the quality of life after surgery, but long-term changes due to surgery without the effect of cachexia remain unclear. Patients with esophageal cancer who underwent esophagectomy and did not experience cancer recurrence for 3 years were analyzed. The psoas muscle mass index (PMI) was assessed before surgery and 7 days, 1 year, and 3 years after surgery. Patients with no change or increased PMI within 7 days after surgery were categorized into the Nondecreasing-PMI group, whereas those with decreased PMI were categorized into the Decreasing-PMI group. Eighty-four and 51 patients were categorized into the Nondecreasing- and Decreasing-PMI groups, respectively. The Decreasing-PMI group had a higher incidence rate of anastomotic leakage than the Nondecreasing-PMI group (25% vs. 12%, respectively; P = 0.042). Moreover, the Decreasing-PMI group showed a significantly greater decrease in the PMI 1 year after surgery than the Nondecreasing-PMI group (-9.2% vs. -4.0%, respectively; P = 0.048). However, although the Decreasing-PMI group had a greater decrease in the PMI than the Nondecreasing-PMI group, no significant difference was observed 3 years after surgery (-9.8% vs. -5.3%, respectively; P = 0.115). A decrease in PMI in the acute phase after esophagectomy may contribute to a long-term decrease in the PMI. Intensive interventions may be beneficial for these patients to improve their long-term quality of life.

Comparison of hand-sewn and circular stapled esophagogastric anastomoses in the neck after esophagectomy for thoracic esophageal cancer: a propensity score-matched analysis

Esophagectomy is a highly invasive surgical procedure; however, anastomotic leakage is one of the major surgical complications that should be prevented. Institutions have their own inherited or specialized anastomosis methods. The superior anastomosis procedure remains unknown despite the many studies to determine the optimal method. The present study enrolled 341 patients who underwent esophagectomy at Keio University Hospital, Tokyo, Japan, between January 2009 and January 2019. The anastomosis method was changed from circular stapled anastomosis to hand-sewn anastomosis in February 2014 to reduce the risk of anastomotic leakage. We retrospectively compared short-term results (anastomotic leakage and stricture) between hand-sewn and circular stapled anastomoses. Analysis of heterogeneity after propensity score matching between the 107 patients in the hand-sewn anastomosis group and 107 patients in the circular stapled anastomosis group revealed almost equal distributions. The incidence rate of anastomotic leakage was significantly lower in the hand-sewn anastomosis group than in the circular stapled anastomosis group (9 vs. 20%, hazard ratio: 2.521; 95% confidence interval: 1.112-5.716; P = 0.027). No significant difference was found in the incidence of anastomotic stricture (16 vs. 18%, P = 0.844). Furthermore, no significant difference was found in the incidence of anastomotic leakage in any of the tumor locations between the two anastomosis procedures. For esophagogastric anastomosis in the neck after esophagectomy, hand-sewn anastomosis is superior to circular stapled anastomosis with regard to reducing the risk of anastomotic leakage.

Tumor Burden Monitoring with Circulating Tumor DNA During Treatment in Patients with Esophageal Squamous Cell Carcinoma

BACKGROUND

To guide appropriate treatment strategy, an accurate tumor monitoring modality that reflects tumor burden during neoadjuvant treatment is required for esophageal squamous cell carcinoma (ESCC). We aimed to investigate the clinical utility of circulating tumor DNA (ctDNA) in plasma in patients who received neoadjuvant chemotherapy (NAC) followed by esophagectomy.

PATIENTS AND METHODS

Longitudinally collected plasma samples for ctDNA combined with genomic DNA from primary lesions were obtained from patients with histologically confirmed ESCC who underwent NAC followed by subtotal esophagectomy. Next-generation sequencing was performed to identify mutations from the plasma and the primary tumor. The relationships between changes in ctDNA and the pathological response and recurrence were assessed in patients with locally advanced ESCC.

RESULTS

In pretreatment samples from 13 patients, multiple concordant mutations in ctDNA and primary tumors were observed in 11 patients (85%), who were classified as ctDNA positive before treatment. The ctDNA positive rate after NAC correlated with the pathological response (responders, 25%; nonresponders, 100%; p = 0.007). The risk of recurrence increased significantly in patients with positive ctDNA after surgery in analysis of 16 patients; the 1-year recurrence-free survival rates were 90 and 0% in ctDNA-negative and ctDNA-positive groups, respectively (p = 0.0008). In two patients with postoperative recurrence, ctDNA was detected approximately 5.5 months earlier than the diagnosis using radiographical imaging.

CONCLUSIONS

ctDNA is a promising biomarker for predicting pathological response and postoperative recurrence in ESCC. To demonstrate the external validity, we are currently preparing a multicenter prospective study.

Search for the Majorana Nature of Neutrinos in the Inverted Mass Ordering Region with KamLAND-Zen

The KamLAND-Zen experiment has provided stringent constraints on the neutrinoless double-beta (0νββ) decay half-life in ^{136}Xe using a xenon-loaded liquid scintillator. We report an improved search using an upgraded detector with almost double the amount of xenon and an ultralow radioactivity container, corresponding to an exposure of 970 kg yr of ^{136}Xe. These new data provide valuable insight into backgrounds, especially from cosmic muon spallation of xenon, and have required the use of novel background rejection techniques. We obtain a lower limit for the 0νββ decay half-life of T_{1/2}^{0ν}>2.3×10^{26}  yr at 90% C.L., corresponding to upper limits on the effective Majorana neutrino mass of 36-156 meV using commonly adopted nuclear matrix element calculations.

Safety and efficacy of conversion therapy for esophageal squamous cell carcinoma

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Background: The increased efficacy of multimodality treatment allows for the consideration of conversion therapy with curative intent for initially unresectable esophageal squamous cell carcinoma (ESCC) after initial treatment. Conversion therapy has been commonly defined as treatment aiming at a curable intention after tumors initially deemed technically or oncologically unresectable or only marginally resectable respond to chemotherapy. In our institute, conversion therapy is considered for patients with para-aortic lymph node-positive advanced ESCC who have no other distant metastasis, if the para-aortic lymph node metastases have disappeared after systemic chemotherapy. Methods: There were 33 patients of unresectable esophageal cancer with positive para-aortic lymph node metastases from 2011 to 2021. Nine of these patients showed disappearance of para-aortic lymph node metastases and underwent conversion therapy, seven patients underwent esophagectomy and two patients underwent chemoradiation therapy (CRT). Characteristics, short-term and long-term results of these nine cases are studied. Results: All of the nine patients who had para-aortic lymph node metastases were treated with induction DCF (Docetaxel + Cisplatin + 5-FU) therapy as initial treatment. After disappearance of para-aortic lymph node metastasis, minimally invasive or open esophagectomy was performed in seven patients and CRT was performed in two patients. In operation group, four patients (57%) had Clavien-Dindo grade 2 or 3 complications, but no perioperative death was observed. In CRT group, there was no toxicity over CTCAE grade 3. Four of nine patients (44%) had recurrence, within mediastinum lymph node, abdominal lymph node or adrenal gland. 3-year DFS was 56% and 3-year OS was 67%. Conclusions: Conversion therapy is safe and feasible in cases that responded to systemic chemotherapy. Some cases showed good prognosis. Long-term survival is expected with conversion therapy. In our study, there was few cases that could led to conversion therapy. It is expected that more aggressive initial chemotherapy will be used in the future for patients with positive para-aortic lymph node metastases with a view to conversion therapy.

Comparison of changes in body-fat mass and reflux esophagitis among reconstruction methods for proximal gastrectomy

BACKGROUND

Although proximal gastrectomy (PG) is a function-preserving surgical option, it remains unclear as to which reconstruction method can prevent reflux and maintain body composition.

METHODS

Patients who underwent PG at Keio University between April 2011 and November 2018 were analyzed. Changes in the subcutaneous and visceral adipose tissues were comparatively assessed before and after a year of surgery for three common reconstruction methods. We also compared the endoscopic findings of reflux esophagitis and the number of patients prescribed with proton-pump inhibitor after a year of surgery.

RESULTS

This study included 76 patients, of which 33 patients underwent esophagogastrostomy with a circular stapler (CS), 35 under double flap (DF) reconstruction, and 8 underwent double tract (DT) reconstruction. Comparing esophagogastrostomy (CS and DF) and DT showed that esophagogastrostomy could significantly preserve both subcutaneous and visceral adipose tissues (P < 0.001 and P = 0.04, respectively). However, the change in the subcutaneous and visceral adipose tissues was comparable between CS and DF. As for reflux esophagitis, DF showed the lowest incidence rate for esophagitis and the least number of patients who were prescribed a proton-pump inhibitor.

CONCLUSION

DF is a relatively better reconstruction method for preserving fat mass and preventing reflux among the three common reconstruction methods.

Effects of let-7a microRNA and C-C chemokine receptor type 7 expression on cellular function and prognosis in esophageal squamous cell carcinoma

BACKGROUND

C-C chemokine receptor type 7 (CCR7) participates in chemotactic and metastatic responses in various cancers, including in esophageal squamous cell carcinoma (ESCC). The microRNA (miRNA) let-7a suppresses migration and invasion of various types of cancer cells by downregulating CCR7 expression.

METHODS

The expression levels of CCR7 and let-7a were measured in the cell lines, tumor, and peritumoral tissues of ESCC patients. KYSE cell lines were transfected with synthetic let-7a miRNA and a let-7a miRNA inhibitor, and their CCR7 expression levels as well as invasive ability were evaluated. A highly invasive cell line was established via an invasion assay, and CCR7 expression level along with let-7a level was subsequently evaluated. Cancer cells overexpressing CCR7 were injected subcutaneously into mice, and the animals were monitored for tumor growth along with lymph node metastasis.

RESULTS

A negative correlation between CCR7 and let-7a expression was observed in the ESCC cell lines as well as in tissue samples from patients. Synthetic let-7a decreased CCR7 expression level, while the let-7a inhibitor increased it. In vitro, the established highly invasive cancer cells with high and low levels of CCR7 and let-7a expression, respectively, exhibited a greater invasive ability than the wild-type cell line. The cells were associated with tumor growth and lymph node metastasis in mice. Patients in the high-CCR7/low-let-7a group had the worst prognosis, with a five-year recurrence free survival (5-RFS) rate of 37.5%, followed by the high-CCR7/high-let-7a (5-RFS: 60.0%) and low-CCR7 (5-RFS: 85.7%; p = 0.038) groups.

CONCLUSIONS

The expression of CCR7 was downregulated by let-7a miRNA in esophageal cancer cells. The decrease in let-7a expression level led to the increased expression level of CCR7 in ESCC cells, consequently increasing their invasive ability and malignancy and resulting in a worse prognosis for ESCC patients.

TRIAL REGISTRATION

Retrospectively registered.

Electron Signatures of Reconnection in a Global eVlasiator Simulation

Geospace plasma simulations have progressed toward more realistic descriptions of the solar wind-magnetosphere interaction from magnetohydrodynamic to hybrid ion-kinetic, such as the state-of-the-art Vlasiator model. Despite computational advances, electron scales have been out of reach in a global setting. eVlasiator, a novel Vlasiator submodule, shows for the first time how electromagnetic fields driven by global hybrid-ion kinetics influence electrons, resulting in kinetic signatures. We analyze simulated electron distributions associated with reconnection sites and compare them with Magnetospheric Multiscale (MMS) spacecraft observations. Comparison with MMS shows that key electron features, such as reconnection inflows, heated outflows, flat-top distributions, and bidirectional streaming, are in remarkable agreement. Thus, we show that many reconnection-related features can be reproduced despite strongly truncated electron physics and an ion-scale spatial resolution. Ion-scale dynamics and ion-driven magnetic fields are shown to be significantly responsible for the environment that produces electron dynamics observed by spacecraft in near-Earth plasmas.

Neutrophil-to-lymphocyte ratio change predicts histological response to and oncological outcome of neoadjuvant chemotherapy for esophageal squamous cell carcinoma

BACKGROUND

Evaluating tumor response to neoadjuvant chemotherapy (NAC) is important to predict survival and to select the optimal strategy for patients with esophageal cancer. The aim of this study is to investigate the relation between neutrophil-to-lymphocyte ratio (NLR) change after NAC and histological response and oncological outcomes in patients with esophageal cancer.

METHODS

This study enrolled 209 patients who underwent NAC and thoracic esophagectomy for esophageal cancer as the primary treatment between 2000 and 2019 in our department. Several predictors of survival including NLR change, which was calculated as post-NAC NLR/pre-NAC NLR, were investigated. We used classification and regression tree (CART) analysis to determine the optimal cutoff values of NLR change for the prediction of histological response.

RESULTS

The best cutoff value of NLR change was 0.55 using the CART analysis. Then we divided all patients into two groups; the patients with NLR change below the cutoff were allocated to the NLR reduction group (n = 53), whereas the patients with NLR change above the cutoff were allocated to the no-NLR reduction group (n = 156). NLR change was identified as a significant predictor for histological responder (odds ratio 3.80; 95% confidence interval (CI) 1.69-8.58; p = 0.001) and recurrence-free survival (hazard ratio 0.55; 95% CI 0.33-0.89; p = 0.015) in multivariable analysis.

CONCLUSION

The present study demonstrated that NLR change is associated with both histological response to and oncological outcomes of NAC for patients with esophageal cancer. NLR change can help not only to predict survival, but also to facilitate personalized multidisciplinary treatment.

Magnetic Field Annihilation in a Magnetotail Electron Diffusion Region With Electron-Scale Magnetic Island

We present observations in Earth's magnetotail by the Magnetospheric Multiscale spacecraft that are consistent with magnetic field annihilation, rather than magnetic topology change, causing fast magnetic-to-electron energy conversion in an electron-scale current sheet. Multi-spacecraft analysis for the magnetic field reconstruction shows that an electron-scale magnetic island was embedded in the observed electron diffusion region (EDR), suggesting an elongated shape of the EDR. Evidence for the annihilation was revealed in the form of the island growing at a rate much lower than expected for the standard X-type geometry of the EDR, which indicates that magnetic flux injected into the EDR was not ejected from the X-point or accumulated in the island, but was dissipated in the EDR. This energy conversion process is in contrast to that in the standard EDR of a reconnecting current sheet where the energy of antiparallel magnetic fields is mostly converted to electron bulk-flow energy. Fully kinetic simulation also demonstrates that an elongated EDR is subject to the formation of electron-scale magnetic islands in which fast but transient annihilation can occur. Consistent with the observations and simulation, theoretical analysis shows that fast magnetic diffusion can occur in an elongated EDR in the presence of nongyrotropic electron effects. We suggest that the annihilation in elongated EDRs may contribute to the dissipation of magnetic energy in a turbulent collisionless plasma.

Automated Surgical-Phase Recognition for Robot-Assisted Minimally Invasive Esophagectomy Using Artificial Intelligence

BACKGROUND

Although a number of robot-assisted minimally invasive esophagectomy (RAMIE) procedures have been performed due to three-dimensional field of view, image stabilization, and flexible joint function, both the surgeons and surgical teams require proficiency. This study aimed to establish an artificial intelligence (AI)-based automated surgical-phase recognition system for RAMIE by analyzing robotic surgical videos.

METHODS

This study enrolled 31 patients who underwent RAMIE. The videos were annotated into the following nine surgical phases: preparation, lower mediastinal dissection, upper mediastinal dissection, azygos vein division, subcarinal lymph node dissection (LND), right recurrent laryngeal nerve (RLN) LND, left RLN LND, esophageal transection, and post-dissection to completion of surgery to train the AI for automated phase recognition. An additional phase ("no step") was used to indicate video sequences upon removal of the camera from the thoracic cavity. All the patients were divided into two groups, namely, early period (20 patients) and late period (11 patients), after which the relationship between the surgical-phase duration and the surgical periods was assessed.

RESULTS

Fourfold cross validation was applied to evaluate the performance of the current model. The AI had an accuracy of 84%. The preparation (p = 0.012), post-dissection to completion of surgery (p = 0.003), and "no step" (p < 0.001) phases predicted by the AI were significantly shorter in the late period than in the early period.

CONCLUSIONS

A highly accurate automated surgical-phase recognition system for RAMIE was established using deep learning. Specific phase durations were significantly associated with the surgical period at the authors' institution.

Clinical Features of Recurrence Pattern with Lung Metastasis After Radical Esophagectomy for Thoracic Esophageal Cancer

BACKGROUND

One of the difficulties in the treatment of esophageal cancer surgery is the high rate of postoperative recurrence. After esophagectomy, distant metastatic recurrence frequently occurs in the lung. This study aimed to determine the clinical features of a recurrence pattern with lung metastasis.

METHODS

The current study analyzed data from 138 patients who had postoperative recurrence of esophageal cancer after a radical esophagectomy. According to the recurrence pattern at the time of initial diagnosis, the patients were classified into two groups as follows: those with lung metastasis and those without.

RESULTS

Twenty-three of the 138 investigated patients had a recurrence pattern with lung metastasis. Salvage surgery and postoperative pneumonia (p = 0.041 and 0.030, respectively) were identified as risk factors for recurrence pattern with lung metastasis in multivariate analysis. When we compared the sites of primary esophageal tumors, we found that the frequencies of distant metastases, such as lung and liver metastases, as well as pleural/peritoneal dissemination, were higher in the mid and distal esophageal tumors. Patients with a recurrence pattern showing lung metastasis alone had a better overall and post-recurrence survival than those with other recurrence patterns (p < 0.001 and p < 0.001).

CONCLUSIONS

In patients who had postoperative recurrence after esophagectomy for thoracic esophageal cancer, salvage surgery, and postoperative pneumonia were significantly related to recurrence pattern with lung metastasis. Postoperative recurrence with lung metastasis alone had a better prognosis than other recurrence patterns; therefore, when pulmonary recurrence is suspected, performing intensive examinations for early diagnosis is critical.

Elevation of the Prognostic Factor Plasma Fibrinogen Reflects the Immunosuppressive Tumor Microenvironment in Esophageal Squamous Cell Carcinoma

INTRODUCTION

Despite previous reports on the clinical significance of plasma fibrinogen (FNG) levels as a prognostic indicator of ESCC, its underlying mechanism remains unclear. This study aimed to validate the prognostic impact of plasma FNG levels and clarify its relationship with primary tumors in patients with esophageal squamous cell carcinoma (ESCC).

METHODS

The prognostic impact of FNG was evaluated in patients with ESCC who underwent esophagectomy between 2000 and 2019. The RNA sequencing of the primary ESCC site, which was from pre-operative biopsy, was performed, followed by immune profile characterization using an immunogram. Those profiles were assessed via the immunohistochemical staining of tumor-associated macrophages (TAMs) and clinical response to nivolumab.

RESULTS

Multivariate analysis identified FNG as a significant prognostic factor in ESCC. The immunogram suggested an immunosuppressive tumor environment in the high-FNG group. Immunostaining with the TAM markers CD163 and CD204, revealed that the high-FNG group had significantly higher number of TAMs compared with the low-FNG group. The immunosuppressive characteristics were clinically validated in patients with metastatic ESCC; those who had elevated FNG levels showed poor response to nivolumab.

CONCLUSION

This study successfully validated the prognostic impact of plasma FNG levels in an expanded cohort with ESCC. Accordingly, our findings showed that increased plasma FNG reflects an immunosuppressive tumor microenvironment that facilitates tumor progression and poor responses to nivolumab.

Short-term outcomes of robot-assisted minimally invasive esophagectomy with extended lymphadenectomy for esophageal cancer compared with video-assisted minimally invasive esophagectomy: A single-center retrospective study

BACKGROUND

The safety and feasibility of robot-assisted minimally invasive esophagectomy (RAMIE) remain unclear. The aim of this study was to compare the short-term outcomes of RAMIE with extended lymphadenectomy and conventional minimally invasive esophagectomy (MIE) in order to investigate the safety and feasibility of RAMIE.

METHODS

A retrospective analysis of 87 patients who underwent minimally invasive esophagectomy at our institution between April 2018 and March 2020 was made, assigning 22 in the RAMIE group and 65 in the MIE group. Short-term clinical outcomes and clinical baseline data were compared.

RESULTS

The baseline characteristics were comparable. No significant difference in median thoracic phase blood loss and median number of dissected mediastinal lymph nodes were observed. The median operative time of thoracic approach was significantly longer in the RAMIE group than the MIE group (305 minutes [221-397] vs 227 minutes [133-365], P < .0001). With respect to postoperative complications such as recurrent laryngeal nerve paralysis (Clavien-Dindo ≥ grade II) (RAMIE 4.6% vs MIE 17%, P = .11) and postoperative pneumonia (Clavien-Dindo ≥ grade III) (RAMIE 9% vs MIE 23%, P = .13), no significant difference was observed. The patients in the RAMIE group had a better postoperative swallowing function (P = .023) and were able to start oral food intake significantly earlier (P = .007). The median hospital stay was significantly shorter in the RAMIE group than in the MIE (23 days vs 35 days, P = .009).

CONCLUSIONS

RAMIE with extended lymphadenectomy was safe and feasible for esophageal cancer and resulted in improved postoperative swallowing function and shorter postoperative hospital stay.

Exposure to a Postoperative Hypercoagulable State Predicts Poor Prognosis After Transthoracic Esophagectomy in Patients with Esophageal Cancer

PURPOSE

The contribution of postoperative coagulation-fibrinolysis status to prognosis is yet to be fully investigated. Thus, in this study, we aimed to elucidate the relationship between postoperative hypercoagulable state (PHS) after transthoracic esophagectomy and long-term outcome in patients with esophageal cancer.

METHODS

Patients with esophageal cancer who underwent transthoracic esophagectomy were selected from a prospectively maintained database. Based on the trend of postoperative plasma fibrin-fibrinogen degradation product (FDP) levels, patients with PHS were identified. The prognostic significance of PHS was evaluated via multivariate analysis using the Cox regression model.

RESULTS

Based on the plasma FDP levels of 172 patients that reached a plateau between POD5 and POD7, we calculated the mean FDP value of POD5, 6, and 7, setting a median value as a cutoff. Consequently, 87 patients were classified as PHS. The overall survival (OS) in the PHS group was determined to be significantly lower than in the non-PHS group (5-year OS; 68% and 80%, p = 0.012). Recurrence-free survival (RFS) in the PHS group was significantly lower than in the non-PHS group (5-year RFS; 60% and 79%, p = 0.017). Using the pathological stage as a covariate in the multivariate analysis, PHS was an independent prognostic factor of OS [hazard ratio (HR) 2.517, p = 0.009] and RFS (HR 1.905, p = 0.041).

CONCLUSIONS

PHS was found to be an independent negative prognostic factor in patients with esophageal cancer. Possible improvement of the oncological outcome by early postoperative intervention with anticoagulants should be explored in clinical trials.

Exploratory prospective study of the influence of radical esophagectomy on perioperative physical activity in patients with thoracic esophageal cancer

Sarcopenia, which involves two important aspects, namely skeletal muscle loss and decreased physical function, was suggested as a poor prognostic factor in esophageal cancer surgery. The purpose of this study was to clarify the perioperative change in daily physical activity and propose effective preventive strategies. We prospectively enrolled patients with esophageal cancer who were scheduled to undergo radical esophagectomy. Their daily physical activities were recorded using an accelerometer before surgery, immediately after discharge, and 6 months after surgery. The relationships of physical activity level and the perioperative factors, especially skeletal muscle change, with the risk factors of low daily activity level were investigated. The data of 20/28 enrolled patients were analyzed. The mean activity level of the 20 patients decreased after discharge and subsequently recovered on postoperative month 6. The percentage of activity levels >1.5 metabolic equivalents/day after discharge significantly correlated to the change rate in total muscle cross-sectional area from baseline to POM 6 (r = 0.452, P = 0.045). In a stepwise multiple regression analysis, age, neoadjuvant chemotherapy, and anastomotic leakage were identified as negative associated factors of activity time at >1.5 metabolic equivalents at postoperative month 6. Activity level immediately after discharge was significantly associated with skeletal muscle loss at postoperative month 6 in patients with esophageal cancer who underwent esophagectomy. Elderly patients and patients who received neoadjuvant chemotherapy and had an anastomotic leakage might require intensive prevention. Prospective interventions aimed at increasing daily activity can prevent sarcopenia.

Preoperative maximum phonation time as a predictor of pneumonia in patients undergoing esophagectomy

PURPOSE

Esophagectomy is a highly invasive procedure, associated with several postoperative complications including pneumonia, anastomotic leakage, and sepsis, which may result in multiorgan failure. Pneumonia is considered a major predictor of poor long-term prognosis, so its prevention is important for patients undergoing surgery for esophageal cancer.

METHODS

The subjects of this study were 137 patients who underwent esophagectomy at Keio University Hospital, Tokyo, Japan, between January, 2012 and December, 2016. Patients who underwent R0 or R1 resection or esophagectomy with organ excision were included. Patients who underwent salvage surgery or resection of recurrent laryngeal nerve, and those with preoperative recurrent laryngeal nerve palsy, were excluded. We investigated the effect of the maximum phonation time on the development of postoperative pneumonia.

RESULTS

Pneumonia developed more frequently in patients with a long operative time, clinically left recurrent nerve lymph node metastasis, and a short preoperative maximum phonation time (p = 0.074, 0.046, and 0.080, respectively). Pneumonia was also more common in men with an abnormal maximum phonation time (p = 0.010).

CONCLUSIONS

The maximum phonation time is a significant predictor of postoperative pneumonia after esophagectomy in men.

Association of anastomotic leakage with long-term oncologic outcomes of patients with esophagogastric junction cancer

BACKGROUND

Despite improvements in surgical procedures and peri-operative patients management, the postoperative complications in esophagogastric junction (EGJ) cancer remain high because of technical aspects. Several studies have indicated the negative influence of postoperative infectious complications on long-term survival after gastrointestinal surgery. However, no study has shown the association between postoperative complications and long-term survival of patients with EGJ cancer.

AIM

To elucidate influence of postoperative complications on the long-term outcomes of patients with EGJ cancer.

METHODS

A total of 122 patients who underwent surgery for EGJ cancer at the Keio University were included in this study. We examined the association between complications and long-term oncologic outcomes.

RESULTS

In all patients, the 3-year overall survival (OS) rate was 71.9%, and the recurrence-free survival (RFS) rate was 67.5%. Compared with patients without anastomotic leakage, those with anastomotic leakage had poor median OS (8 mo vs not reached, P = 0.028) and median RFS (5 mo vs not reached, P = 0.055). Among patients with cervical anastomosis, there were not significant differences between patients with and without anastomotic leakage. However, among patients who underwent intrathoracic anastomosis, patients with anastomotic leakage had significantly worse OS (P = 0.002) and RFS (P = 0.005).

CONCLUSION

Anastomotic leakage was significantly associated with long-term oncologic outcomes of patients with EGJ cancer, especially those who underwent intrathoracic anastomosis. Cervical anastomosis with subtotal esophagectomy may be an option for the patients who are at high risk for anastomotic leakage.

Clinical Significance of Endoscopic Response Evaluation to Predict the Distribution of Residual Tumor after Neoadjuvant Chemotherapy for Esophageal Squamous Cell Carcinoma

PURPOSE

To appropriately adopt the organ preservation approach, including subsequent chemoradiotherapy (CRT) in patients who respond to neoadjuvant chemotherapy (NAC), the distribution of residual disease, including pathological lymph nodes (LNs) and recurrence site, needs to be recognized preoperatively. This study was designed to evaluate whether endoscopic response evaluation can predict residual tumor distribution.

METHODS

Patients with esophageal squamous cell carcinoma who underwent transthoracic esophagectomy (TTE) were retrospectively reviewed. Endoscopic responder (ER) to NAC was defined according to primary tumor endoscopic findings. Recurrence-free survival (RFS), overall survival (OS), and residual tumor patterns were compared between groups.

RESULTS

Of 193 patients, 40 (20%) were classified as ER. ERs showed significantly better RFS and OS. The pN location was found within the primary tumor and cN field in 88% of ERs, which was significantly higher than non-ERs at 63% (p = 0.004). Furthermore, the postoperative recurrence incidence in the distant organ was significantly lower in the ERs than the non-ERs (8%, 32%, respectively, p = 0.002). Residual disease, including postoperative initial recurrence, existed within the same field as the primary tumor and cN in 88% of ERs, significantly higher than 42% in the non-ERs (p < 0.001).

CONCLUSIONS

Endoscopic response evaluation can preoperatively predict distribution of residual tumors after NAC, which could help radiation field selection in subsequent definitive CRT when patients prefer to omit TTE. Along with improvements in NAC response rate, this could facilitate organ preservation in patients who respond to NAC.

Structure of a Perturbed Magnetic Reconnection Electron Diffusion Region in the Earth's Magnetotail

We report in situ observations of an electron diffusion region (EDR) and adjacent separatrix region in the Earth's magnetotail. We observe significant magnetic field oscillations near the lower hybrid frequency which propagate perpendicularly to the reconnection plane. We also find that the strong electron-scale gradients close to the EDR exhibit significant oscillations at a similar frequency. Such oscillations are not expected for a crossing of a steady 2D EDR, and can be explained by a complex motion of the reconnection plane induced by current sheet kinking propagating in the out-of-reconnection-plane direction. Thus, all three spatial dimensions have to be taken into account to explain the observed perturbed EDR crossing. These results shed light on the interplay between magnetic reconnection and current sheet drift instabilities in electron-scale current sheets and highlight the need for adopting a 3D description of the EDR, going beyond the two-dimensional and steady-state conception of reconnection.

Clinical usefulness of sputum culture on the first postoperative day to predict early postoperative pneumonia after esophagectomy for esophageal cancer

BACKGROUND

Postoperative pneumonia is a serious prognostic problem that can appear after esophagectomy in patients with esophageal cancer. The past reports have considered the usefulness of perioperative culture examinations for predicting postoperative pneumonia; however, the direct relationship between these examinations and postoperative complications remains unclear.

METHODS

This study retrospectively analyzed esophageal cancer patients who underwent esophagectomy followed by sputum culture on the first postoperative day. The bacterial species that frequently cause hospital-acquired pneumonia were chosen as the target species in this study. The relationship between culture examination and postoperative pneumonia within one week (7 days) after esophagectomy was investigated.

RESULTS

Sputum cultures on the first postoperative day were investigated in 238 patients who underwent esophagectomy for esophageal cancer. Forty-one patients developed pneumonia within one week after surgery. The target bacterial species were detected in 26 of 238 sputum cultures (10.9%). In the univariate analysis, a Brinkman index, detection of target bacterial species, detection of Gram-positive cocci, and Gram-negative rods were significantly associated with postoperative pneumonia. In the three independent multivariate analyses, the target bacterial species, Gram-positive cocci, and Gram-negative rods (p = 0.001, 0.042, and < 0.001) were individually identified as independent risk factors of postoperative pneumonia in addition to a Brinkman index.

CONCLUSIONS

Detection of target bacterial species by sputum culture on the first postoperative day after esophagectomy was an independent risk factor of postoperative pneumonia within 7 days after surgery. Prospective studies for the prevention of early postoperative pneumonia using sputum culture on the first postoperative day can be considered.

Association of preoperative sarcopenia with postoperative dysphagia in patients with thoracic esophageal cancer

BACKGROUND

The purpose of the current study was to clarify the relationship between clinical features of dysphagia after esophagectomy and preoperative sarcopenia.

METHODS

A total of 187 cases were included in the current study. The psoas cross-sectional area on pre-treatment computed tomography was measured in thoracic esophageal cancer patients who underwent curative resection. The psoas muscle index (PMI) cut-off levels for sarcopenia were 6.36 cm2/m2 for men and 3.92 cm2/m2 for women. Swallowing function was evaluated using videofluoroscopic swallowing study (VFSS) and fiberoptic endoscopic evaluation of swallowing (FEES) at postoperative days 7-15, and classified according to the food intake level scale (FILS). Perioperative swallowing rehabilitation was performed in all cases.

RESULTS

In the 187 included patients, the median PMI was 5.42 cm2/m2 for men and 3.43 cm2/m2 for women, and 133 cases (71%) met the sarcopenia criteria. The FILS <4 (no oral intake) was 15% in the non-sarcopenia group, and 38% in the sarcopenia group (P = 0.003). There was no significant difference in the incidence of postoperative complications, including pneumonia and re-admission due to pneumonia, between the two groups. Preoperative sarcopenia and recurrent laryngeal nerve palsy were be independent risk factors for postoperative dysphagia.

CONCLUSIONS

Sarcopenic patients with esophageal cancer develop postoperative dysphagia more often than non-sarcopenic patients. Prehabilitation and nutritional support for patients with preoperative sarcopenia could play an important role to mitigate postoperative dysphagia.

The Results of Sentinel Node Mapping for Patients with Clinically Early Staged Gastric Cancer Diagnosed with pT2/deeper Tumors

BACKGROUND

Sentinel node (SN) mapping based on the SN concept has been applied to early gastric cancer. However, it is still controversial whether or not the oncological safety is ensured in case pathological stage was advanced in these patients. The aim of this study was to investigate the validity of SN mapping in patients with clinically early staged gastric cancer diagnosed with pT2/deeper tumors.

METHODS

We retrospectively analyzed 40 patients with a diagnosis of cT1N0 or cT2N0 single-lesion gastric cancer who were shown to have pT2 or deeper tumors after gastrectomy with SN mapping. We adopted a dual-tracer method using a radioactive colloid and blue dye to detect SNs. The diagnostic accuracy and distribution of SNs at each tumor site were analyzed.

RESULTS

Of the 40 patients, 24 (60%) were postoperatively diagnosed as pT2, and 16 (40%) as pT3 or T4. SNs were detected in all patients. The false negative rate was 9% (1/11), and in that patient, the non-SN metastasis was observed within the SN basin. Diagnostic accuracy was 98% (39/40). Overall distribution of SNs was similar to that for patients with early gastric cancer. No significant differences in overall and recurrence-free survival were observed between the patients who underwent standard gastrectomy and those who underwent function-preserving gastrectomy, based on the results of SN mapping.

CONCLUSIONS

Our results confirmed validity of SN mapping for patients with clinically early staged gastric cancer diagnosed with pT2/deeper tumors after gastrectomy. Closed surveillance without additional surgical treatment is an option for these patients.