bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantification of pulmonary functional MRI: state-of-the-art and emerging image processing methods and measurements
Authors: Sharma Maksym , Wyszkiewicz Paulina V , Desaigoudar Vedanth , Guo Fumin , Capaldi Dante PI , Parraga Grace
Published: September 2022

Pulmonary functional magnetic resonance imaging (PfMRI) provides a way to non-invasively map and measure the spatial distribution of pulmonary ventilation, perfusion and gas-exchange abnormalities with unprecedented detail of functional processes at the level of airways, alveoli and the alveolar-capillary membrane. Current PfMRI approaches are dominated by hyperpolarized helium-3 (3He) and xenon-129 (129Xe) gases, which both provide rapid (8–15 s) and well-tolerated imaging examinations in patients with severe pulmonary diseases and pediatric populations, whilst employing no ionizing radiation. While a number of review papers summarize the required image acquisition hardware and software requirements needed to enable PfMRI, here we focus on the image analysis and processing methods required for reproducible measurements using hyperpolarized gas ventilation MRI. We start with the transition in the literature from qualitative and subjective scoring systems to quantitative and objective measurements which enable precise quantification of the lung’s critical structure-function relationship. We provide an overview of quantitative biomarkers and the relevant respiratory system parameters that may be measured using PfMRI methods, outlining the history of developments in the field, current methods and then knowledge gaps and typical limitations. We focus on hyperpolarized noble gas MR image processing methods used for quantifying ventilation and gas distribution in the lungs, and discuss the utility and applications of imaging biomarkers generated through these techniques. We conclude with a summary of the current and future directions to further the development of image processing methods, and discuss the remaining challenges for potential clinical translation of these approaches and their integration into standard clinical workflows.
Investigation of core impurity transport in DIII-D diverted negative triangularity plasmas
Authors: Sciortino F , Howard N T , Odstrčil T , Austin M , Bykov I , Chrystal C , Haskey S R , Lore J D , Marinoni A , Marmar E S , Meneghini O , Paz-Soldan C , Rodriguez-Fernandez P , Smith S P , Thome K E
Published: September 2022

Tokamak operation at negative triangularity has been shown to offer high energy confinement without the typical disadvantages of edge pedestals (Marinoni et al 2021 Nucl. Fusion
61 116010). In this paper, we examine impurity transport in DIII-D diverted negative triangularity experiments. Analysis of charge exchange recombination spectroscopy reveals flat or hollow carbon density profiles in the core, and impurity confinement times consistently shorter than energy confinement times. Bayesian inferences of impurity transport coefficients based on laser blow-off injections and forward modeling via the Aurora package (Sciortino et al 2021 Plasma Phys. Control. Fusion
63 112001) show core cross-field diffusion to be higher in L-mode than in H-mode. Impurity profile shapes remain flat or hollow in all cases. Inferred radial profiles of diffusion and convection are compared to neoclassical, quasilinear gyrofluid, and nonlinear gyrokinetic simulations. Heat transport is observed to be better captured by reduced turbulence models with respect to particle transport. State-of-the-art gyrokinetic modeling compares favorably with measurements across multiple transport channels. Overall, these results suggest that diverted negative triangularity discharges may offer a path to a highly-radiative L-mode scenario with high core performance.
Observation of MHD-correlated blobs during internal reconnection events in VEST
Authors: Jung E.C. , Na Y.S. , Kim S. , Jeong W.I. , Park J.-K. , Hahm T.S. , Ghim Y.-c. , Hwang Y.S.
Published: September 2022

Internal reconnection events (IREs), one of the relaxation events driven by internal magnetohydrodynamic (MHD) instabilities in fusion plasmas, are accompanied by a strongly MHD-correlated blob at the edge in the Versatile Experiment Spherical Torus spherical tokamak. The MHD-correlated blob plays a significant role in the onset and the strength of IREs. Various techniques analyzing visible camera images show correlated waveforms between blobs and magnetic fluctuations, and they produce visualized images of corotating structures of the MHD modes and the MHD-correlated blobs. In the images, a phase drag in the rotations of the two structures initially appears and vanishes on the verge of IREs. IREs maintaining the phase drag, however, leads to a less violent impact in terms of current decrease and magnetic field bursting. In addition, the MHD-correlated blobs are followed by the increasing degree of nonlinear interactions between the internal MHD mode and high-frequency broadband fluctuations (>60 kHz) at the edge. These results suggest that boundary plasmas can impact internally driven relaxation events via MHD-correlated edge phenomena.
Improved heat and particle flux mitigation in high core confinement, baffled, alternative divertor configurations in the TCV tokamak
Authors: Raj Harshita , Theiler C. , Thornton A. , Février O. , Gorno S. , Bagnato F. , Blanchard P. , Colandrea C. , de Oliveira H. , Duval B.P. , Labit B. , Perek A. , Reimerdes H. , Sheikh U. , Vallar M. , Vincent B.
Published: September 2022

Nitrogen seeded detachment has been achieved in the tokamak a configuration variable (TCV) in alternative divertor configurations (ADCs), namely X-divertor and X-point target, with and without baffles in H-mode plasmas with high core confinement. Both ADCs show a remarkable reduction in the inter-ELM particle and heat fluxes to the target compared to the standard divertor configuration. 95%–98% of the inter-ELM peak heat flux to the target is mitigated as a synergetic effect of ADCs, baffling, and nitrogen seeded detachment. The effect of divertor geometry and baffles on core-divertor compatibility is investigated in detail. The power balance in these experiments is also investigated to explore the physics behind the observed reduction in heat fluxes in the ADCs.
Polarization switching induced by domain wall sliding in two-dimensional ferroelectric monochalcogenides
Authors: Petralanda Urko , Olsen Thomas
Published: September 2022

The ability to switch between distinct states of polarization comprises the defining property of ferroelectrics. However, the microscopic mechanism responsible for switching is not well understood and theoretical estimates based on coherent monodomain switching typically overestimates experimentally determined coercive fields by orders of magnitude. In this work we present a detailed first principles characterization of domain walls (DWs) in two-dimensional ferroelectric GeS, GeSe, SnS and SnSe. In particular, we calculate the formation energies and migration barriers for 180∘ and 90∘ DWs, and then derive a general expression for the coercive field assuming that polarization switching is mediated by DW migration. We apply our approach to the materials studied and obtain good agreement with experimental coercive fields. The calculated coercive fields are up to two orders of magnitude smaller than those predicted from coherent monodomain switching in GeSe, SnS and SnSe. Finally, we study the optical properties of the compounds and find that the presence of 180∘ DWs leads to a significant red shift of the absorption spectrum, implying that the density of DWs may be determined by means of simple optical probes.
Analysis of ecological security evaluation and zoning threshold determination of typical energy industrial area based on PSR model
Authors: Zhang Yue , Zhang Liyuan , Guo Wei , Yu Kanhua , Bo Ya’nan
Published: September 2022

Ecological security is the main way to measure the effects of urbanization and industrialization in developing regions on the ecological environment. As an important coal chemical industry base in China, Taiyuan is located in the Loess Plateau, resulting in great pressure on the ecological environment. Based on the pressure-state-response (PSR) model, this study selected 15 evaluation indicators to evaluate the ecological security of 10 counties(districts/city) in Taiyuan City. Using the spatial principal component analysis (SPCA) method and GIS technology to simulate and analyze the ecological security distribution of this area, for the first time, the typical method and average method were used to divide the threshold of the ecological security level to achieve a more reasonable ecological security classification method. The results showed that from 2000 to 2016, the ecological security level of Taiyuan city and its surrounding areas was relatively low, mainly concentrated in Xinghualing, Yingze and Jiancaoping districts, while the ecological security level of Loufan county, Qingxu County, Gujiao city and Yangqu County was relatively high. Among these, energy mining and urbanization have had a relatively obvious impact on ecological security. It could provide more detailed ideas for the protection of ecological security in different areas and enrich the research on the ecological security of important coal chemical bases.
Magnetic couplings in edge-sharing high-spin d
7 compounds
Authors: Winter Stephen M
Published: September 2022

High-spin d
7 Co(II) compounds have recently been identified as possible platforms for realizing highly anisotropic and bond-dependent couplings featured in quantum-compass models such as the celebrated Kitaev model. In order to evaluate this potential, we consider all symmetry-allowed contributions to the magnetic exchange for ideal edge-sharing bonds. Though a combination of ab-initio and cluster many-body calculations we conclude that bond-dependent couplings are generally suppressed in favor of Heisenberg exchange for real materials. Consequences for several prominent materials including Na2Co2TeO6 and BaCo2(AsO4)2 are discussed.
Frequency-specific gaze modulation of emotional face processing in the human amygdala
Authors: Guex Raphael , Meaux Emilie , Mégevand Pierre , Domínguez-Borràs Judith , Seeck Margitta , Vuilleumier Patrik
Published: September 2022

Determining the social significance of emotional face expression is of major importance for adaptive behavior, and gaze direction provides critical information in this process. The amygdala is implicated in both emotion and gaze processing, but how and when it integrates expression and gaze cues remains unresolved. We tackled this question using intracranial electroencephalography in epileptic patients to assess both amygdala (n = 12) and orbitofrontal cortex (OFC; n = 11) time-frequency evoked responses to faces with different emotional expressions and different gaze directions. As predicted, self-relevant threat signals (averted fearful and directed angry faces) elicited stronger amygdala activity than self-irrelevant threat (directed fearful and averted angry faces). Fear effects started at early latencies in both amygdala and OFC (~110 and 160 ms, respectively), while gaze direction effects and their interaction with emotion occurred at later latencies. Critically, the amygdala showed differential gamma band increases to fearful averted gaze (starting ~550 ms) and to angry directed gaze (~470 ms). Moreover, when comparing the 2 self-relevant threat conditions among them, we found higher gamma amygdala activity for averted fearful faces and higher beta OFC activity for angry directed faces. Together, these results reveal for the first time frequency-specific effects of emotion and gaze on amygdala and OFC neural activity.
165. DIVERSITY OF PERINEURAL INVASION AND THEIR PREDICTIVE ROLE IN PROGNOSIS OF ESOPHAGEAL SQUAMOUS CELL CARCINOMA
Authors: Zhu Jianfei , Ma Yu , Wang Hongtao
Published: September 2022

Perineural invasion (PNI) is regarded as an important pathological feature of cancer invasion. The aim of this study was to explore the type of PNI and its impact on the prognosis of esophageal squamous cell carcinoma (ESCC).

Patients with ESCC who underwent surgical treatment at Shaanxi Provincial People’s Hospital were included for the retrospective analysis. Postoperative specimens from all patients were evaluated for PNI using haematoxylin and eosin (H&E) staining and S100 immunohistochemistry (IHC). We determined the correlation between PNI status and clinical outcomes.

Among 349 ESCC cases, PNI was identified in 127 patients (36.3%), and four subtypes of PNI were identified. The median disease-free survival (DFS) of PNI-negative patients was 43.9 months, while that of PNI-positive patients was 19.9 months (P < 0.001). Multivariate analysis showed that PNI (P = 0.001) were independent factors affecting DFS of ESCC. Similarly, PNI-positive patients had poorer overall survival (OS) than PNI-negative patients (26.4 months vs 62.5 months, P < 0.001). We also found that among the four subtypes of PNI, patients with PNI-a subtype had better DFS (P = 0.002) and OS (P = 0.002) than patients with the other three subtypes (PNI-b, c, d).

PNI is an important form of ESCC invasion. Its status is closely related to the factors of TNM staging and can be used as a supplement, especially for pN-negative patients. PNI is also an independent prognostic factor for ESCC, and it stratified analysis should be carried out for patients with ESCC.
172. THE MEDIASTINOSCOPIC RADICAL ESOPHAGECTOMY WITH A TRANS-BICERVICAL APPROACH USING INTRAOPERATIVE NERVE MONITORING (IOMN)
Authors: Tokairin Yutaka , Nagai Kagami , Shiobara Hiroyuki , Ando Masayuki
Published: September 2022

We developed ‘mediastinoscopic esophagectomy with lymph node dissection’ (MELD), performed under pneumomediastinum via a trans-bicervical and transhiatal approach using cadavers. A clinical trial on the feasibility and safety of MELD showed it to be useful for complete mediastinal lymph node dissection. We report the indications and novel aspects of MELD.

MELD was indicated for patients of thoracic esophageal cancer without bulky primary lesions or lymph node metastases. MELD was performed in 16 patients. First, 101R and part of the 106recR lymph nodes were dissected in open surgery. After attaching an APS electrode for intraoperative nerve monitoring (IOMN) to the right vagus nerve, open surgery was changed to the pneumomediastinal method. The dorsal side of the esophagus was dissected along the visceral sheath. The 106tbL lymph nodes and the106recR lymph nodes were dissected using a right trans-cervical pneumomediastinal approach. The 106recL lymph nodes were dissected using a left trans-cervical pneumomediastinal approach.

The median pneumomediastinal operation time was 320 minutes. The median amount of bleeding was 230 mL, and the median postoperative hospital stay was 16 days. Regarding complications, eight patients developed recurrent laryngeal nerve palsy (right, n = 3; left, n = 2; bilateral, n = 3), but no patients required conversion to thoracotomy, and no leakage, pneumonia, or operative deaths occurred. After incorporating the use of IOMN, the incidence of recurrent laryngeal nerve palsy was drastically reduced recurrent laryngeal nerve palsy was drastically decrease.

Previous clinical trials shown that MELD can retrieve the mediastinal lymph nodes at the same level as thoracoscopic esophagectomy. The incidence of recurrent laryngeal nerve palsy was reduced by IONM; thus, MELD is considered a feasible procedure for radical esophagectomy.
177. TORIPALIMAB COMBINATION WITH CHEMOTHERAPY AND SUBSEQUENT RADIATION IN PATIENTS WITH STAGE IV ESOPHAGEAL CARCINOMA，A PROSPECTIVE PHASE II STUDY (TR-EAT TRIAL)
Authors: Wang Qifeng , Lei Wei , Li Baisen , Liang Long , Wan Gang , Lang Jinyi , Li Tao
Published: September 2022

Immune checkpoint inhibitor therapy combined with chemotherapy is safe and effective in treating advanced esophageal carcinoma; however, some patients still experience tumor progression and/or metastasis in short term. Whether and when the addition of radiotherapy to immunotherapy combined with chemotherapy improves the prognosis of patients with advanced/metastatic esophageal carcinoma needs to be investigated.

Patients with unresectable stage IV ESCC with oligometatsis were enrolled. The patients were treated with two cycles of toripalimab (240 mg d1,Q3w) combined with induction chemotherapy (paclitaxel 135–175 mg/m2,d1 + carboplatin AUC = 4–6,d1,Q3W), sequentially add the radiation (30–50 Gy in 15–25 fractions), SBRT for lung, liver and bone oligometasis followed by maintenance treatment with toripalimab (240 mg d1,Q3W) for 1 year. The primary objective is to evaluate the progression-free survival (PFS), and the secondary objective is objective response rate (ORR), 2-year overall survival (OS) rates, the safety and tolerability of patients to treatment, and the identification of the changes in the healthrelated quality of life of patients.

Now, 23 and 22 patients were screened and enrolled. After two cycles of induction therapy, 18 patients were evaluated. The results showed complete response (CR) in 0 patients, partial response (PR) in 6, stable disease (SD) in 9 and progressive disease (PD) in 3(1/3 occured fistula). ORR was 33.3% and DCR was 83.3%. For patients with PR + SD underwent radiotherapy, 11 patients finished plan RT were evaluated. The results showed CR in 1 patient, PR in 8, SD in 2 and PD in 0. ORR was 81.8% and DCR was 100%. Most patients experienced only grade 1–2 adverse effects and laboratory abnormalities.

The interim analysis showed that the sequential radiotherapy significantly improve the ORR in the initial treatment of advanced esophageal squamous cell carcinoma (ESCC) after the treatment with toripalimab combined with chemotherapy. The initial results are encouraging and the final results are to be expected.
182. LAPAROSCOPIC-ASSISTED SINGLE-PORT MEDIASTINOSCOPIC ESOPHAGECTOMY CAN PROVIDE A SAFE AND EFFECTIVE SURGICAL OPTION FOR PATIENTS WITH SPECIFIC ESOPHAGEAL CANCERS
Authors: Wu Xiangwen , Li Wenhao , Gan Xiangfeng , Cao Qingdong
Published: September 2022

The majority of traditional minimally invasive esophagectomies are transthoracic esophagectomies. However, transthoracic esophagectomy is often difficult to perform in some patients with pulmonary insufficiency, severe pleural adhesions, chest deformities, and poor tolerance for single-lung ventilation. For this reason, we propose laparoscopic-assisted single-port mediastinoscopic esophagectomy as a potential surgical treatment for patients who are unsuitable for transthoracic esophagectomy. The goal of this study was to report the effectiveness and safety of its treatment.

This study retrospectively collected clinical data from hard-to-reach transthoracic patients who underwent laparoscopic-assisted single-port mediastinoscopic esophagectomy at our center from October 2016 to August 2021 to report their perioperative treatment outcomes. Data for continuous variables are expressed as mean ± standard deviation, and categorical variables are expressed as n [%]. All data were analyzed using SPSS 25.0 software.

A total of 8 cases were included and all completed the surgery successfully. The average operating time was 266.14 min, the average intraoperative bleeding was 114.29 mL, the average number of lymph nodes obtained was 13.29, the average number of recurrent laryngeal nerve (RLN) lymph nodes was 3.14, the rate of RLN lymph nodes obtained was 75%, the average postoperative hospital stay was 22.29 days. Postoperative complications included type I vocal cord paralysis [37.5%], anastomotic leak [25%], pneumonia [12.5%], pleural effusion [25%], and type I Chyle Leak [12.5%], with no perioperative deaths. There was one recurrence and no death within 1 year postoperatively.

The results of this study suggest that laparoscopic-assisted single-port mediastinoscopic esophagectomy can provide a safe and effective treatment option for patients with esophageal cancer who have difficulty undergoing transthoracic esophagectomy and can achieve a more satisfactory short-term survival outcome.
183. IMPACTS OF NEOADJUVANT CHEMORADIOTHERAPY ON THE IMMUNE LANDSCAPE OF ESOPHAGEAL SQUAMOUS CELL CARCINOMA
Authors: Wen Jing , Fang Shuogui , Hu Yi , Xi Mian , Weng Zelin , Fu Jianhua , Yang Hong
Published: September 2022

Neoadjuvant chemoradiation (neoCRT) followed by surgery is the most common approach for locally advanced resectable esophageal squamous cell carcinoma (ESCC) patients. Tumor microenvironment (TME) has been implicated in tumor response to treatment. Here, we aimed to investigate the impacts of neoCRT on the complex immune landscape in ESCC TME.

Single-cell RNA sequencing (scRNA-seq) were conducted to examine the neoCRT-driven cellular and molecular dynamics in ESCC samples obtained before and after neoCRT. Consensus non-negative matrix factorization analysis was applied to decipher coherent gene expression programs of tumor cells. Activities of pathways and transcription factors of individual cells were analyzed by gene set variation and gene regulatory network analyses, respectively. Cell fate tracing was inferred by RNA velocity analysis. Multiplex fluorescent immunohistochemistry was performed to validate the changes of immune cells identified by scRNA-seq in another 25 pairs of pre- and post-neoCRT ESCC samples.

Expression programs of cell cycle, adhesion, stress response, and epithelial differentiation in pre-treatment tumor cells related to neoCRT response. Infiltration of CD8+ T cells with exhausted cells dominant increased in both major and minor responders after neoCRT. Treg cell differentiation decreased after neoCRT in major responders but increased in minor ones. NeoCRT promoted the maturation of cDC1s but decreased the number of cDC2s. Expression of M2 macrophage markers increased after neoCRT. Immune-related pathways were enriched at higher levels in CD8+ T cells and macrophages of major responders as compared to minor responders before neoCRT, which was reversed after neoCRT.

Our comprehensive picture of the neoCRT-related dynamic immune ecosystem provides deeper insights into immunological mechanisms associated with ESCC response to neoCRT, which may aid in future development of immune-strategies for improving ESCC treatment.
190. IMPLEMENTATION OF THE ESOPHAGECTOMY COMPLICATIONS CONSENSUS GROUP DEFINITIONS: THE BENEFITS OF SPEAKING THE SAME LANGUAGE
Authors: Muir Duncan , Antonowicz Stefan , Whiting Jack , Low Donald , Maynard Nick
Published: September 2022

In 2015 the Esophagectomy Complications Consensus Group (ECCG) reported consensus definitions for complications after oesophagectomy. This aimed to reduce variation in complication reporting, attributed to heterogeneous definitions. This systematic review aimed to describe the implementation of this definition-set, including the effect on complication frequency and variation.

A systematic literature review was performed, identifying all observational and randomised studies reporting complication frequencies after oesophagectomy since the ECCG publication. Recruitment periods before and subsequent to the index ECCG publication date were included. Coefficients of variance were calculated to assess outcome heterogeneity. Study quality was assessed using the Newcastle-Ottawa score.

Of 144 studies which met inclusion criteria, 70 (48.6%) used ECCG definitions. The median number of separately reported complication types was five per study; only one study reported all ECCG complications. The coefficients of variance of the reported frequencies of eight of the ten most common complications was reduced in ECCG adopting studies vs non-adopting studies (p = 0.036) (see Figure 1). Among ECCG studies, the frequencies of post-operative pneumothorax, re-intubation and pulmonary emboli were reduced in 2020–2021, compared to 2015–2019 (p = 0.006, 0.034 and 0.037 respectively). There was no difference in the quality of ECCG adopting studies and non-adopting studies.

The ECCG definition-set has reduced variation in oesophagectomy morbidity reporting. This adds greater confidence to the observed gradual improvement in outcomes with time, and its ongoing use and wider dissemination should be encouraged. However, only a handful of outcomes are widely reported, and only rarely is it used in its entirety.
191. THE IMPACT OF PREHABILITATION IN UPPER GASTROINTESTINAL (GI) CANCER UNDERWENT SURGERY
Authors: Shariff Ramizah , Jahit Mohammad Shukri , Chee Tee Sze , Harith Abdul Aziz , Shahabuddin Nurul Hannan , Adibi Saiyidah Adila Mohd
Published: September 2022

Major upper gastrointestinal (GI) surgery always poses unique perioperative challenges and high post-surgical complications. Prehabilitation encompasses of exercise, nutrition and medical optimization prior to surgery. There is an emerging evidence to show prehabilitation plays a significant role in reducing morbidity and mortality associated with major upper GI surgery by improving patient’s functional status. Its role in improving postoperative outcomes such as length of stay (LOS) is less established.

An interventional study conducted among oesophageal and gastric cancer patients who undergone oesophagectomy and gastrectomy surgery. All the preoperative patients are assessed by dietician and nutrition therapy will be intiated based on ESPEN guideline. A standard set of physical and breathing exercise are adopted. Study characteristics, ECOG status, handgrip, peak flow meter and spirometry are obtained. Primary outcome is impact of prehabilitation on functional capacity. Secondary outcomes include post-operative length of stay and complications based on Clavien-Dindo classification.

Thirty one (31) patients who were recruited [gastrectomy (n = 21) and oesophagectomy (n = 10)]. Mean age was 59.2 ± 8.9 years. 21(67.7%)was male patients. Majority of the participants were SGA B (51.6%) with good ECOG status of 1(61.3%). Most of the diseases were in advanced stage [stage III (54.9%), stage IV (9.7%)].After prehabilitation, handgrip strength, peak flow meter and spirometry were significantly higher before surgery (20.9 vs 26.1, p = 0.002; 322.2 vs 419.3, p = 0.002; 77.4% vs 90.3%, p = 0.007 respectively). No significant difference in LOS and post operative complications were observed.

Prehabilitation was associated with significant increase in functional capacity after intervention. Hence prehabilitation should be strongly recommended among patient undergoing major upper GI surgery to accelerate recovery from cancer surgery. However, there is insufficient data to demonstrate its role in improving clinical outcomes, including LOS and post operative complications.
192. DYSPNOEA IMPROVES FOLLOWING PARAOESOPHAGEAL HERNIA REPAIR AND IS NOT NECESSARILY A CONTRAINDICATION TO SURGERY
Authors: Paredes Steven Ronald , Khoma Oleksandr , Wong Ngar Lok Joshua , Falk Gregory
Published: September 2022

Paraoesophageal hernias (PEH) are often symptomatic and can lead to life-threatening complications including volvulus and ischaemia. Dyspnoea was recently reported as the most prevalent symptom of giant PEHs, although it has been perceived by some as a contraindication to surgery. The aim of this study is to evaluate the effect of surgery on resolution of dyspnoea amongst patients with giant hiatus hernia defined as greater than 30% of the stomach above the diaphragm.

Data were extracted from a prospectively maintained single-surgeon database containing records of patients undergoing composite hernia repair. Patients who underwent standardised composite laparoscopic repair of giant PEH without mesh prosthesis between March 2009 and December 2015 and had documented dyspnoea were included. Patients were reviewed post-operatively at 6 weeks, 3 months, 12 months, and then annually unless more frequent visits were clinically indicated. The primary outcome of the analysis was the difference in patient-reported pre-operative and post-operative dyspnoea. Secondary outcomes included differences in pre-operative and post-operative dysphagia and clinical aspiration as well as recurrence of PEH of any size.

Inclusion criteria were met by 154 patients. There were 127 females (82.5%) and 27 males (17.5%). The average age at time of operation was 71.2 years (range 49–93, SD 9.66). The average hernia size was 64%, based on intraoperative evaluation by the surgeon (range 30–100%, SD 20.2). After surgery, there was a significant improvement in all symptoms: dyspnoea (100% pre-operatively, 2.6% post-operatively, P¬ < 0.001), dysphagia (46.1% pre-operatively, 15.6% post-operatively, P < 0.001) and clinical aspiration (9.1% pre-operatively, 1.3% post-operatively, P = 0.002). Hernia recurrence was found in 37 patients (24.0%) amongst whom dyspnoea was rare (5.4%, 2 patients).

This study suggests that dyspnoea resolves following laparoscopic repair of giant paraoesophageal hernia. This may be explained by the effect of surgical repair on improving hernia-related atrial compression, pulmonary congestion and reduced lung capacities. The presence of dyspnoea should be regarded as an indication rather than a barrier to surgery. Therefore, we recommend all patients with giant hiatus hernia to be assessed by a specialist surgical service.
194. THE IMPACT OF PREHABILITATION IN UPPER GASTROINTESTINAL (GI) CANCER UNDERWENT MAJOR SURGERY
Authors: Shariff Ramizah , Jahit Mohammad Shukri , Chee Tee Sze , Harith Abdul Aziz , Shahabuddin Nurul Hannan , Adibi Saiyidah Adila Mohd
Published: September 2022

Major upper gastrointestinal (GI) surgery always poses unique perioperative challenges and high post-surgical complications. Prehabilitation encompasses of exercise, nutrition and medical optimization prior to surgery. There is an emerging evidence to show prehabilitation plays a significant role in reducing morbidity and mortality associated with major upper GI surgery by improving patient’s functional status. Its role in improving postoperative outcomes such as length of stay (LOS) is less established.

An interventional study conducted among oesophageal and gastric cancer patients who undergone oesophagectomy and gastrectomy surgery. All the preoperative patients are assessed by dietician and nutrition therapy will be intiated based on ESPEN guideline. A standard set of physical and breathing exercise are adopted. Study characteristics, ECOG status, handgrip, peak flow meter and spirometry are obtained. Primary outcome is impact of prehabilitation on functional capacity. Secondary outcomes include post-operative length of stay and complications based on Clavien-Dindo classification.

Thirty one (31) patients who were recruited [gastrectomy (n = 21) and oesophagectomy (n = 10)]. Mean age was 59.2 ± 8.9 years. 21(67.7%)was male patients. Majority of the participants were SGA B (51.6%) with good ECOG status of 1(61.3%). Most of the diseases were in advanced stage [stage III (54.9%), stage IV (9.7%)].After prehabilitation, handgrip strength, peak flow meter and spirometry were significantly higher before surgery (20.9 vs 26.1, p = 0.002; 322.2 vs 419.3, p = 0.002; 77.4% vs 90.3%, p = 0.007 respectively). No significant difference in LOS and post operative complications were observed.

Prehabilitation was associated with significant increase in functional capacity after intervention. Hence prehabilitation should be strongly recommended among patient undergoing major upper GI surgery to accelerate recovery from cancer surgery. However, there is insufficient data to demonstrate its role in improving clinical outcomes, including LOS and post operative complications.
202. THE UTILITY OF TISSUE OXYGEN SATURATION DURING GASTRIC TUBE RECONSTRUCTION WITH CERVICAL ANASTOMOSIS FOR ESOPHAGECTOMY
Authors: Ishii Kenjiro , Tsubosa Yasuhiro , Haneda Ryoma , Inoue Masazumi , Mayanagi Shuhei
Published: September 2022

Background: One cause of anastomotic leakage after radical esophagectomy is blood flow insufficiency at the cervical anastomosis site. Therefore, evaluation of blood flow in the gastric tube is important in preventing anastomotic leakage. In this study, we focused on the repeated measurement of tissue oxygen saturation (rSO2) before and after raising the gastric tube to the cervical area and also at the actual anastomotic site in the gastric tube.

Methods: Eighteen patients were studied. rSO2 was measured at the tip (point pre 0) and 2, 4, and 6 cm on the distal side of the tip (point pre 1, pre 2, and pre 3) before the gastric tube was raised to the cervical site through the retrosternal route. After that, rSO2 was measured at the tip, 2 and 4 cm on the distal side of the tip (points post 0, post 1, and post 2), the actual anastomotic site (point AN). The relationship between rSO2 scores and the rate of anastomotic leakage was determined.

Results: The mean rSO2 at pre 0, pre 1, pre 2, and pre 3 were 48.9%, 52.3%, 54.8%, and 56.9%, respectively (p < 0.05). The mean rSO2 at post 0, post 1, and post 2 were 47.8%, 50.5%, and 52.3%, respectively, and the rSO2 at point AN was 52.1%.

Anastomotic leakage was found in 6 patients. The rSO2 at points pre 0, pre 1, and pre 2, post 0 and point AN were significantly lower in patients with anastomosis leakage than those without it (p < 0.05).

Conclusion: Tissue oxygen saturation monitoring was a useful indicator of blood flow insufficiency in the gastric tube during radical esophagectomy.
204. THE TUMOUR IMMUNE MICROENVIRONMENT IN OESOPHAGEAL ADENOCARCINOMA HAS PROGNOSTIC SIGNIFICANCE
Authors: Lonie James , Brosda Sandra , Aoude Lauren , Bonazzi Vanessa , Patel Kalpana , Lampe Guy , Koufariotis Lambros , Addala Venkateswar , Wood Scott , Thomas Janine , Walpole Euan , Mai Tao , Ackland Stephen , Martin Jarad , Burge Matthew , Finch Robert , Karapetis Christos , Shannon Jenny , Nott Louise , Bohmer Robert , Wilson Kate , Barnes Elizabeth , Zalcberg John , Smithers B Mark , Simes John , Price Timothy , Gebski Val , Watson David , Pearson John , Waddell Nic , Dolcetti Riccardo , Barbour Andrew
Published: September 2022

Oesophageal adenocarcinoma (OAC) is a deadly disease with an increasing incidence globally. Treatment outcomes with traditional therapy have largely plateaued and responses to immunotherapy are modest at best, necessitating the need for better biomarker driven selection. We aimed to unravel the tumour neoantigen landscape and immune microenvironment in OAC patients to aid improved patient selection and inform novel immunotherapy trials.

To characterise the tumour immune microenvironment and neoantigen landscape of OACs, we performed DNA sequencing (n = 117) and RNA sequencing (n = 115) on biopsies taken at pre-treatment endoscopy. Using expression-based computational methods we analysed transcriptomic data to profile infiltration levels of 28 immune cell populations and their functional orientation, as well as stromal signatures and immune checkpoint molecules. TCGA data was used for as a validation cohort. Tumour neoantigens were predicted using the pVAC-Seq pipeline.

Using an immune based classification based on the tumour microenvironment composition, we identified three distinct phenotypes; immune-enriched (IE), heterogeneously-infiltrated (HI), and immune-cold (IC). The IE group showed improved survival compared to both HI and IC, with HI showing the worst survival. The HI-group showed no difference in stromal scores to the IE group, but showed significantly decreased adaptive-immune cell infiltration, indicating that an immunosuppressive stromal compartment may be driving outcomes for these patients. No difference was seen in total or quality neoantigen load between groups, but high correlation with antigen processing machinery is seen.

Our analysis expands the knowledge of the relatively unknown tumour immune microenvironment of OAC. We have identified three immune TME-phenotypes with prognostic utility with current standard of care therapies; which may also act as potential immunotherapy biomarkers. This is being explored further in ongoing immune microenvironment research and will guide future translational studies.
211. STUDENT (CROWD SOURCED) ASSESSMENT OF LAPAROSCOPIC ASSISTED PERCUTANEOUS NEEDLE JEJUNOSTOMY PLACEMENT IS EQUIVALENT TO EXPERT ASSESSMENT, EXCEPT FOR PROCEDURE-SPECIFIC STEPS
Authors: Van Veer Hans , Van der Biest Femke , Corcoles Laurence , Van den Bergh Gert , Nafteux Philippe , Depypere Lieven
Published: September 2022

Objective and Structured Assessment of Technical Skills (OSATS) is an important and frequently used method to give feedback on surgical skills during surgical training. Feedback is usually given by qualified surgeons, but their availability is often limited. Aim of our study was to investigate whether OSATS performed by novice medical students and students trained in a laparoscopic jejunostomy simulation setup was equivalent to OSATS performed by experts in laparoscopic assisted percutaneous needle jejunostomy placement.

Fifty-six volunteers (32 inexperienced students, 12 trained students and 12 expert surgeons) were invited to participate. An instruction video with the procedure’s essential steps was displayed on an online survey platform. Thereafter five edited videos with essential steps of the procedure, performed by operators with a different level of expertise, were shown. Each video was followed by a standardized OSATS form, assessing nine different procedural aspects: fluency of the entire procedure, use of instruments, tissue respect, placement of stitches, tissue bridge between bowel and wall, submucosal needle tunneling, advancing the catheter, camera use and end result. Nonparametric statistics were used.

Thirty-seven (66%) volunteers—21 novice students (66%), 8 trained students (67%) and 8 surgeons (67%)—completed all five forms within 30 days. Median time to complete OSATS forms for novice students, trained students and experts was 22, 21 and 14.5 days respectively (p = 0.88). Median time needed per video was 825, 881 and 793 seconds respectively (p = 0.60). Average total scores per item showed no differences between novice students, trained and experts, except for items submucosal needle tunneling” (p = 0.0082) and advancing the catheter” (p = 0.0154) which both were rated higher by experts than by both groups of students.

Using standardized OSATS to evaluate laparoscopic assisted percutaneous needle jejunostomy placement, steps with common laparoscopic skills were rated equally by novice students, trained students and experts. These skills can be correctly evaluated without advanced training of the evaluator. Two procedure-specific items were rated differently by experts, compared to students. These procedure-specific items probably need more advanced training, explaining the different appreciation of the assessed manipulations by expert surgeons.
212. LAPARO-GASTROSCOPIC ESOPHAGECTOMY: A RETROSPECTIVE STUDY OF A PIONEER CASE SERIES
Authors: Shen Yaxing , Zhang Yiqun , Fang Yong , He Mengjiang , Fan Hong , Tan Lijie
Published: September 2022

Transcervical gastroscopic esophagectomy pioneered the gastroscope from intraluminal to extraluminal dissection for esophageal cancer. Its integration with laparoscopic gastric conduit formation, known as laparo-gastroscopic esophagectomy (LGE), was introduced an updated procedure of transhiatal esophagectomy. Herein, we report a case series to demonstrate its safety and efficacy.

We began performing LGE in July 2020, and herein we retrospectively reviewed the results of primary cohort performed from July 2020 to September 2021, in which endoscopic sentinel lymph node (SLN) navigation, an addition to the LGE procedure, was performed on patients 6 to 11. Patient clinical features, operative outcomes and complications were collected and analyzed. The follow-up results of the cohort was recorded.

LGE was successfully in 10 patients and 1 patient was excluded due to mucosal skip metastasis to cervical esophagus observed during SLN inspection. There were no intraoperative conversions or complications, and all patients tolerated the procedure well. Postoperatively, 2 patients developed pulmonary complications (One case of aspiration and 1 case of pleural effusion). SLNs were detected and removed in the last 4 cases, and frozen section examinations were negative. All patients were discharged within 10 days postoperatively, and no patient died at the latest follow-up in January 2022.

Based on the primary cohort that received LGE, the procedure shows promising surgical results, and the addition of SLN will further guarantee the oncological efficacy.
218. DYSPNOEA IMPROVES FOLLOWING REPAIR OF PARAOESOPHAGEAL HERNIA AND IS NOT NECESSARILY A CONTRAINDICATION TO SURGERY
Authors: Khoma Oleksandr , Wong Ngar Lok Joshua , Mugino Miho , Khoma Maite Jeanne , Van der Wall Hans , Falk Gregory L
Published: September 2022

Paraoesophageal hernias (PEH) are often symptomatic and can lead to life-threatening complications such as volvulus and ischemia. Recently dyspnoea was reported as most prevalent symptom of giant hiatus herniae. The aim of this study is to evaluate the effect of surgery on resolution of dyspnoea amongst patients with giant hiatus hernia defined as greater than 30% of the stomach above the diaphragm.

Data were extracted from a prospectively maintained single surgeon database containing records of patients undergoing composite hernia repair. Patients who underwent composite laparoscopic repair of giant paraoesophageal hernia between March 2009 and December 2015 and had documented dyspnoea were included. Inclusion criteria were met by 154 patients. Primary outcome of the analysis included preoperative and postoperative dyspnoea. Secondary outcomes included complications and post-operative symptoms.

The mean age at time of surgery was 71.2 years (range 49–93, SD 9.66). Surgery resulted in near complete resolution of dyspnoea (2.6% postoperatively, P-value <0.001). Significant improvement was also noted in dysphagia, although not micro-aspiration.

Dyspnoea resolves following laparoscopic repair of giant paraoesophageal hernia. The presence of dyspnoea should be regarded as an indication rather than a barrier to surgery. We recommend all patients with giant hiatus hernia to be assessed by a specialist surgical service.
222. ARE GASTRIC MAPPING BIOPSIES NECESSARY TO DETERMINE THE DISTAL RESECTION MARGIN FOR SIGNET RING ADENOCARCINOMAS OF THE OESOPHAGO-GASTRIC JUNCTION?
Authors: Chaudhury Madhu , Singh Mohan , Ball Chris , Ward Jeremy , Shetty Vinutha Daya , Pursnani Kishore , Turner Paul
Published: September 2022

In our department patients with oesophago-gastric junctional adenocarcinomas with signet ring differentiation undergo a second endoscopy for gastric mapping biopsies to investigate the extent of tumour extension into the proximal stomach. This is due to the perceived aggressive morphology and to avoid a R1 (microscopic positive) resection at the distal margin. Our aim was to elucidate whether gastric mapping endoscopic biopsies are necessary prior to resection in signet ring adenocarcinomas of the oesophago-gastric junction (OGJ).

Patients with operable OGJ adenocarcinomas with signet ring morphology were retrospectively analysed from 2011–2021 from our databank of completed oesophagectomies at our upper gastrointestinal cancer surgical department. From 2014–2021, OGJ adenocarcinomas identified with signet ring differentiation were subjected to a second invasive endoscopy with gastric mapping biopsies to determine the distal ex-tent of microscopic invasion into the cardia and beyond. These were analysed to determine the histopathological yield from gastric mapping biopsies and the number of cases with a positive (R1) distal resection margin.

From 2014, 322 oesophagectomy cases were completed and these were analysed further. Of these, 21.7% (n = 70) were found pre-operatively to have signet ring differentiation and thus underwent a second gastric mapping endoscopy. Within the signet ring morphology cohort, only one patient (1.4%) was found to involve a R1 resection margin which necessitated a second operation involving gastric resection and colonic interposition.

Our results suggest that patients with signet ring adenocarcinoma of the OGJ do not need gastric mapping biopsies to determine the distal margin prior to resection. Although considered a more aggressive subtype of adenocarcinoma, radial infiltration from the tumour does not seem to affect conventional surgical oncological margins.
224. PURSUING ERAS POST-OESOPHAGECTOMY WITHOUT ENTERIC FEEDING TUBES: A 12 YEAR SINGLE CENTRE EXPERIENCE
Authors: Chaudhury Madhu , Shetty Vinutha Daya , Ward Jeremy , Ball Chris , Pursnani Kish , Turner Paul , Singh Mohan
Published: September 2022

Early feeding post oesophagectomy is encouraged. Surgical outcomes from different routes of feeding be it oral, via nasoenteral or jejunostomy tubes remains debatable due to ERAS protocol variations. We present our outcomes from our single regional centre where oesophagectomies are completed without the insertion of nasoenteric or feeding jejunostomy tubes, and therefore oral intake being the sole route of post-operative nutrition.

A retrospective study employed an electronic database of elective Ivor Lewis oesophagectomies from April 2009 to December 2021 at a tertiary upper gastrointestinal cancer centre in the United Kingdom. All patients without nasoenteric or jejunostomy tubes were included in the study, as this is the routine practice. Our practice involves a gradual increase in oral fluids from day 0 to 4, with supplementary intravenous fluid. We introduce a soft diet from the 5th post-operative day. We evaluated patient outcomes using the Clavien-Dindo grade (CDG). Primary outcomes were anastomotic leaks, length of stay, chyle leaks, and 30- and 90-day mortality.

578 Ivor Lewis oesophagectomies were peformed between 2009–2021 without any jejunostomies or nasoenteric tubes inserted. The median age was 63 years old (45–82) with M:F 1.8:1. The median length of stay (LOS) was 13 (3–148) days. Chyle leak was identified in 24 patients (4.2%) and of these 83.3% (n = 20) underwent surgical management with a mortality of 5% (n = 1). 16.7% (n = 4) chyle leaks were managed conservatively with a median LOS of 31 days (14–51), with no mortality. Anastomotic leaks were identified in 26 cases (4.5%), outcomes illustrated in the table. The 30- & 90-day mortality was 0.3% (n = 2) and 0.9% (n = 5).

While the best route of feeding post oesophagectomy remains contentious and variable, we have shown that surgical outcomes from performing oesophagectomies without the insertion of any enteric feeding tubes is feasible and safe. While this challenges conventional paradigm, we demonstrate early oral intake using a well-defined ERAS protocol poses no increased risk of surgical complications and negates the additional risks inherent from jejunal tubes and artificial feeding.