Node Count Research Articles

Evaluation of prognostic significance of histopathological characteristics and tumor-infiltrating lymphocytes for pancreatic cancer survival

With a 5-year survival of ˂ 10%, pancreatic cancer is one of the leading causes of cancer-related deaths. Given the role of the distribution of tumor-infiltrating lymphocyte (TILs) subtypes in the tumor and its microenvironment in predicting prognosis, the development of new targeted therapies based on T-cell adaptive response has gained considerable attention. This study aimed to examine the peritumoral spread of TILs and its relationship with other prognostic parameters and survival. This study included 60 patients with pancreatic cancer who had undergone surgery with follow-up between 2011 and 2021. Demographic characteristics, tumor histopathological features, peritumoral TILs counts, and intratumoral programmed cell death protein-1 (PD-1) and programmed death ligand − 1 (PD-L1) positivity were evaluated. Furthermore, overall survival and their efficacy in predicting survival according to TNM stage were analyzed. The number of cluster differentiation-3 positive (CD3 P) TILs increased with advancing pathological T stage. CD3 P and CD8 P TIL counts were higher in patients with peripancreatic fatty tissue invasion. Patients with PD-L1 positivity and higher TIL counts had better survival rates. PD-L1-negative patients with a low CD8 positive/total lymph node count (P/T) ratio had a longer survival. Moreover, patients with poorly differentiated tumors with low CD3 P/T and CD8 P/T ratios had a longer survival. The CD3 P/T and CD8 P/T ratios were compatible with the automatic and manual measurements. Age, tumor differentiation, N stage, and peritumoral TIL count and subtype, when evaluated together with the presence of PD-L1 in the tumor tissue, may have prognostic significance for survival in patients with pancreatic cancer.

Combined Use of External Iliac Lymph Node Count and Bone Scintigraphy for PJI Diagnosis: A Prospective Study

Background: The reactive enlargement of external iliac lymph nodes and increased blood flow in the infected region are commonly observed in lower limb infections. We aimed to differentiate between aseptic loosening and periprosthetic joint infection (PJI) after joint replacement surgery by quantifying the number of enlarged external iliac lymph nodes and using bone scintigraphy to monitor blood flow. Methods: We recruited 124 patients undergoing revision surgery for aseptic loosening or PJI. All the patients underwent preoperative dual-energy computed tomography (DECT) imaging for external iliac lymph nodes and bone scintigraphy. The diagnostic value was evaluated using ROC curve analysis. Results: The number of enlarged external iliac lymph nodes was significantly higher in the PJI group than in the aseptic failure group (4.0 versus. 1.0, p value < 0.001). The median affected/unaffected side ratio in the blood pool phase of ECT in the PJI group was 1.49, significantly higher than the aseptic failure group’s median ratio of 1.04 (p value < 0.001). The AUC for diagnosing PJI using the number of enlarged lymph nodes alone was 0.91, and when using the bone scintigraphy blood pool phase alone, the AUC was 0.89. When both metrics were combined, the AUC increased to 0.95, which was higher than the AUCs for the ESR (AUC = 0.83), CRP (AUC = 0.76), and synovial fluid PMN% (AUC = 0.62). Conclusions: Combining the enlargement of the lymph node count with the bone scintigraphy blood pool phase is a promising approach for diagnosing PJI.

Impact of contralateral occult neck metastasis in HPV-associated tonsil cancer: Is elective contralateral neck dissection required?

Background: Contralateral elective neck dissection in human papillomavirus (HPV)- associated tonsil cancer is a matter of debate.Objectives: The aim of this study was to analyze rates of contralateral lymph node (LN) metastasis and their prognostic effects on HPV-associated tonsil cancer. We also assessed the necessity of elective contralateral neck dissection.Methods: To investigate the pathologic incidence of and risk factors for contralateral nodal disease in HPV-associated tonsil cancer treated with upfront primary surgery and bilateral neck dissection, the records of 68 patients were reviewed.Results: Six (8.8%) patients displayed pathologic contralateral nodal disease; four of the patients had LN metastasis confirmed in contralateral level II, one patient had LN metastasis in level III, and one patient had multi-level metastasis in contralateral levels II and III. Contralateral LN metastasis showed a significant association with greater depth of invasion (DOI) in primary tumor (p=0.032), count of positive LN (p=0.008), and positive LN ratio of the ipsilateral neck (p=0.01). Patients with contralateral LN metastasis showed a significantly worse five-year overall survival but no significant difference in disease-free survival.Conclusion: HPV-associated tonsil cancer has exceedingly low rates of occult contralateral LN metastasis. However, in cases of ipsilateral multiple node metastases and higher DOI, it may be worth considering elective contralateral neck dissection based on the risk of occult metastasis.

TopoSinGAN: Learning a Topology-Aware Generative Model from a Single Image

Generative adversarial networks (GANs) have significantly advanced synthetic image generation, yet ensuring topological coherence remains a challenge. This paper introduces TopoSinGAN, a topology-aware extension of the SinGAN framework, designed to enhance the topological accuracy of generated images. TopoSinGAN incorporates a novel, differentiable topology loss function that minimizes terminal node counts along predicted segmentation boundaries, thereby addressing topological anomalies not captured by traditional losses. We evaluate TopoSinGAN using agricultural and dendrological case studies, demonstrating its capability to maintain boundary continuity and reduce undesired loop openness. A novel evaluation metric, Node Topology Clustering (NTC), is proposed to assess topological attributes independently of geometric variations. TopoSinGAN significantly improves topological accuracy, reducing NTC index values from 15.15 to 3.94 for agriculture and 14.55 to 2.44 for dendrology, compared to the baseline SinGAN. Modified FID evaluations also show improved realism, with lower FID scores: 0.1914 for agricultural fields compared to 0.2485 for SinGAN, and 0.0013 versus 0.0014 for dendrology. The topology loss enables end-to-end training with direct topological feedback. This new framework advances the generation of topologically accurate synthetic images, with applications in fields requiring precise structural representations, such as geographic information systems (GIS) and medical imaging.

A novel energy efficient QoS secure routing algorithm for WSNs

Quality of Service (QoS) routing protocol is a hot topic in the research field of wireless sensor networks (WSNs). However, the task of identifying an optimal path that simultaneously meets multiple QoS constraints is acknowledged as an NP-hard problem, with its complexity intensifying in proportion to the network’s nodal count. Therefore, a novel heuristic multi-objective trust routing method, the Levy Chaos Adaptive Snake Optimization-based Multi-Trust Routing Method (LCASO-MTRM), is proposed, aiming to enhance link bandwidth while simultaneously reducing latency, packet loss, and energy consumption. The proposed method incorporates innovative chaos and adaptive operators within the LCASO framework. The chaos operator enhances population diversity, expands the solution space, and accelerates the search process. Meanwhile, the adaptive operator improves convergence, enhances robustness, and effectively prevents stagnation. Additionally, this paper introduces a novel multi-objective QoS routing model that integrates a link trust mechanism, allowing for a more accurate assessment of link trust levels and a precise reflection of the current link status. The effectiveness of LCASO-MTRM is demonstrated through simulation comparisons with the Improved Particle Swarm Optimization (IPSO), Improved Artificial Bee Colony Algorithm (IABC), and Cloned Whale Optimization Algorithm (CWOA). Simulation results demonstrate that LCASO-MTRM significantly reduces energy consumption by 49.53%, latency by 22.56%, and packet loss by 40.21%, while increasing bandwidth by 6.13%, outperforming the other algorithms.

Comparative effectiveness of robot-assisted radical cystectomy with intracorporeal urinary diversion vs open radical cystectomy for bladder cancer.

To assess the comparative effectiveness of robot-assisted radical cystectomy (RARC) with intracorporeal urinary diversion (ICUD) vs open radical cystectomy(ORC) for bladder cancer (BC). We conducted a real-life monocentric study including all consecutive patients who underwent RARC with ICUD or ORC for BC at our institution from 2014 to 2023. Uni- and multivariable logistic and Cox regression analyses were used to compare perioperative, oncological and stricture outcomes between both groups by calculating odds (ORs) and hazard (HRs) ratios with their corresponding 95% confidence intervals (CIs), respectively. Overall, 316 patients underwent either RARC with ICUD (n = 228 [72.2%]) or ORC (n = 88 [27.8%]). The perioperative benefits of RARC vs ORC included decreased risks of major blood loss (OR 0.10, 95% CI 0.04-0.23; P < 0.001), perioperative transfusion (OR 0.30, 95% CI 0.16-0.57; P < 0.001), 90-day major complications (OR 0.56, 95% CI 0.29-0.99; P = 0.04), and prolonged initial length of hospital stay (OR 0.20, 95% CI 0.09-0.35; P < 0.001), as well as more days alive and out of the hospital within 90 days of surgery (OR 2.56, 95% CI 1.46-4.6; P < 0.01). In addition, the use of RARC vs ORC was associated with a higher lymph node (LN) count (OR 3.35, 95% CI 1.83-6.30; P < 0.001), while there was no significant difference in recurrence-free (HR 0.72, 95% CI 0.49-1.07; P = 0.1), cancer-specific (HR 0.69, 95% CI 0.43-1.10; P = 0.1), overall (HR 0.76, 95% CI 0.47-1.20; P = 0.3) and uretero-ileal stricture-free (HR 1.18, 95% CI 0.62-2.25; P = 0.6) survival between both groups after a median (interquartile range) follow-up of 42.3 (16.4-73.8) months. Our real-world study supports the effectiveness of RARC with ICUD vs ORC for BC. We generally observed better perioperative outcomes, as well as similar oncological-except for higher LN count-and uretero-ileal stricture outcomes after RARC with ICUD vs ORC.

Path planning of mobile robot based on improved PRM and APF

In the field of mobile robot path planning, the artificial potential field (APF) method has been widely researched and applied due to its intuitiveness and efficiency. However, the APF algorithm often encounters challenges such as local minima and unreachable goals in complex environments. To address these issues, this paper proposes innovative path planning algorithm that integrates the advantages of the probabilistic roadmaps method (PRM), by introducing Sobol sampling and elliptical constraints to enhance PRM. The improved PRM not only reduces redundant nodes but also enhances the quality of sampling points. Furthermore, this paper uses the path nodes from the improved PRM as virtual target points for the APF algorithm, and effectively solves the inherent flaws of the APF algorithm through the segmented processing of the attractive force function and the introduction of a relative distance factor in the repulsive force function. Simulation results show that the algorithm reduces planning time, node count, and path length, demonstrate significant improvements in efficiency and performance. In addition, experiments with omnidirectional mobile robots further confirm the effectiveness and reliability of the algorithm in practical applications.

Lexical Surprisal Shapes the Time Course of Syntactic Structure Building.

When we understand language, we recognize words and combine them into sentences. In this article, we explore the hypothesis that listeners use probabilistic information about words to build syntactic structure. Recent work has shown that lexical probability and syntactic structure both modulate the delta-band (<4 Hz) neural signal. Here, we investigated whether the neural encoding of syntactic structure changes as a function of the distributional properties of a word. To this end, we analyzed MEG data of 24 native speakers of Dutch who listened to three fairytales with a total duration of 49 min. Using temporal response functions and a cumulative model-comparison approach, we evaluated the contributions of syntactic and distributional features to the variance in the delta-band neural signal. This revealed that lexical surprisal values (a distributional feature), as well as bottom-up node counts (a syntactic feature) positively contributed to the model of the delta-band neural signal. Subsequently, we compared responses to the syntactic feature between words with high- and low-surprisal values. This revealed a delay in the response to the syntactic feature as a consequence of the surprisal value of the word: high-surprisal values were associated with a delayed response to the syntactic feature by 150-190 ms. The delay was not affected by word duration, and did not have a lexical origin. These findings suggest that the brain uses probabilistic information to infer syntactic structure, and highlight an importance for the role of time in this process.

Number of Resected Lymph Nodes and Survival Status in Node-Negative Esophageal Squamous Cell Carcinoma: A Cohort Study.

To explore the association between survival status and the number of resected lymph nodes in node-negative esophageal squamous cell carcinoma(ESCC) after surgical treatment. This was a retrospective observational cohort study and data were obtained from the Surveillance, Epidemiology, and End Results program (SEER) and TaiZhou hospital in China. The data for subjects with negative lymph nodes and no distant metastasis (pN0M0) after post-operative pathology were screened. The nonlinear relationship between resected lymph node number and survival status in node-negative ESCC was conducted using restricted cubic spline regression analysis. The association between the number of resected lymph nodes and survival status in node-negative ESCC was evaluated by Cox proportional hazards regression models. Subgroup analysis based on different subgroups was also performed. A total of 999 subjects were included in the study. Restricted cubic spline regression was used to show a U shaped association between the number of resected lymph nodes and survival status in node-negative ESCC, with low count associated with a decreased survival. To elucidate the association, we adjusted for age, sex, race, T stage, TNM (tumor node metastasis classification), location, grade, chemotherapy, and radiotherapy. As the resected lymph node number increased by one node, the survival status was improved by 2% (Hazard ratio(HR) = 0.98, 95% confidence interval (CI) 0.98-0.99). Sensitivity analysis indicate that the effect size and direction in different subgroups are consistent, the results is stability in SEER. A low count of resected lymph nodes correlated with reduced survival in patients with ESCC, where resecting 25 to 28 or more nodes is considered optimal. Larger prospective studies are warranted to confirm these findings.

Prognostic value of a modified pathological staging system for gastric cancer based on the number of retrieved lymph nodes and metastatic lymph node ratio.

The prognosis for gastric cancer (GC) remains grim, underscoring the importance of accurate staging and treatment. Given the potential benefits of using lymph node ratio (LNR) for improved prognostication and treatment planning, it is critical to incorporate examined lymph nodes (ELN) count in an integrated GC staging system. Patients data from the Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2015 was utilized as training set. The Mantel-Cox survival test was used to calculate chi-square values for 40 LNR segments with a 0.025 interval, defining a novel LNR-based N (rN) classification based on the cutoff points. A revised AJCC (rAJCC) staging system was established by replacing the 8th AJCC N staging with a rN classification. The relationship between the ELN count and prognosis or positive lymph node detection was conducted by using multivariable models. The series of the odds ratios and hazard ratios were fitted with a locally weighted scatterplot smoothing (LOWESS) smoother, and the structural break points were determined by Chow test to clarify an optimal minimum ELN count. The integrated GC staging system incorporated both rAJCC system and the ideal ELN count. Discriminatory ability and prognostic homogeneity of the rAJCC and integrated staging system was compared with AJCC staging system in the SEER validation set (2016-2017), the Cancer Genome Atlas Program (TCGA) database, and the Third Affiliated Hospital of Sun Yat-sen University database. The current study found that LNR and ELN count are both significantly associated with the prognosis of GC patients (HR = 0.98, p < 0.001 and HR = 2.51, p < 0.001). Four peaks of the chi-square value were identified as LNR cut-off points at 0.025, 0.175, 0.45 and 0.6 to define a novel rN stage. In comparison to the 8th AJCC staging system, the rAJCC staging system demonstrated significant prognostic advantages and discriminatory ability in the training set (5-Y OS AUC: 71.7 vs. 73.0; AIC: 57,290.7 vs. 57,054.9). The superiority of the rAJCC staging system was confirmed in all validation sets. Using a LOWESS smoother and Chow test, a threshold ELN count of 30 was determined to maximum improvement in the prognosis of node-negative patients without downgrading due to potential metastasis, while also maximizing the detection efficiency of at least one involved lymph node. The integrated staging system, combining the refined rAJCC classification with an optimized ELN count threshold, has demonstrated superior discriminatory performance compared to the standalone rAJCC or the traditional AJCC system. The development of a novel GC staging system, which integrated the LNR-based N classification and the minimum ELN count, has exhibited superior prognostic accuracy, holding promise as a valuable asset in the clinical management of GC. However, it is crucial to recognize the limitations from the retrospective database, which should be addressed in subsequent analyses.

Trends and efficacy of omitting axillary lymph node dissection in early-stage male breast cancer with limited nodal involvement: A population-based cohort study.

The effectiveness of sentinel lymph node biopsy (SLNB) versus axillary lymph node dissection (ALND) in managing early-stage male breast cancer (MBC) patients with T1-2 tumors and limited lymph node metastasis, all receiving radiotherapy, remains uncertain. This study examines trends and survival outcomes for SLNB and ALND in the United States. We conducted a retrospective analysis of the Surveillance, Epidemiology, and End Results (SEER) data from 2010 to 2020 for MBC patients with T1-2 tumors and 1-2 positive lymph nodes undergoing radiotherapy. Patients were classified by nodes removed (SLNB ≤5, ALND ≥10), comparing overall survival (OS) and breast cancer-specific survival (BCSS) between the groups before and after propensity score matching. Of 299 MBC patients analyzed, SLNB usage increased from 18.8% in 2010 to 61.0% in 2020. Multivariable logistic regression highlighted significant associations of SLNB use with diagnosis year, race, surgery type, positive lymph node count, and metastasis size. No significant differences in 5-year OS (77.98% SLNB vs. 85.85% ALND, p = 0.337) or BCSS (91.54% SLNB vs. 94.97% ALND, p = 0.214) were observed. Propensity score matching (96 patients per group) confirmed similar 5-year OS (83.9% for SLNB vs. 82.0% for ALND, p = 0.925) and BCSS (90.1% for SLNB vs. 96.9% for ALND, p = 0.167). SLNB and ALND provide comparable survival outcomes in early-stage MBC patients with limited lymph node metastasis undergoing radiotherapy. The increased utilization of SLNB supports its consideration to reduce surgical morbidity in selected MBC patients despite limited direct evidence.

Comparison and Enhancement in Cluster Based Algorithms in MANET

Building a dynamic MANET network based on mesh technology to improve wireless communication QoS is the main objective of this project. It will be interesting to see how the service performs on mobile ad hoc networks, which are wireless networks without infrastructure management or pre-existing content. The rapid development of mobile, real-time, and multimedia technologies has increased the need for effective programming that completely supports all energy usages. This article compares three algorithms—LEACH, HEED, and MODLEACH—using a variety of comparison techniques. There is a significant amount of difference between the energy levels in MOD-LEACH which is 0.0374092J ,0.0270755J and 0.0270759J in LEACH and HEED algorithms. We can also check MOD-LEACH's dead node count as only 15 as compared to dead nodes in LEACH and HEED which are 34 and 47 respectively. Less dead nodes suggest that MOD-LEACH has the majority of living nodes in the cluster. For the packet loss parameter, MOD-LEACH loses the least number of packets ranging from 120-140 which is less that the ranges 145-165 and above 150 in HEED and LEACH algorithms.

Vascular-oriented D3 lymph node dissection with left colic artery preservation for distal sigmoid colon cancer: a variety of techniques.

One of the approaches to distal sigmoid colon cancer surgical treatment is segmental colonic resection with vascular preservation of left colic artery (LCA). D3 lymph node dissection may technically vary according to different vascular anatomy. This study aims to show the approaches to D3 lymph node dissection with LCA preservation for distal sigmoid colon cancer according to different patterns of inferior mesenteric artery (IMA) branching. CTangiography with 3D reconstruction was routinely performed to identify the IMA branching pattern. Laparoscopic distal sigmoid colon resection with D3 lymph node dissection and left colic artery preservation in standardized fashion was performed in all cases. Data, including clinical, intraoperative, and short-term surgical outcomes, is presented as median numbers (Me) and interquartile range (IQR). Twenty-six patients with distal sigmoid colon cancer were treated with laparoscopic distal sigmoid colon resection. The approach to D3 lymph node dissection varied according to different anatomical variations. There was one conversion (3.8%) and one anastomotic leakage (3.8%) in patients with high BMI. At the same time, there was a high apical lymph node count (Me 3 (IQR 2-5), min-max 0-10) due to the skeletonization of the IMA. The technical aspects of D3 lymph node dissection with left colic artery preservation may vary in different types of LCA and sigmoid artery branching patterns regardless of the standardized anatomical landmarks. The anatomical features should be considered when performing vascular-sparing lymph node dissection.

GPU-enabled extreme-scale turbulence simulations: Fourier pseudo-spectral algorithms at the exascale using OpenMP offloading

Fourier pseudo-spectral methods for nonlinear partial differential equations are of wide interest in many areas of advanced computational science, including direct numerical simulation of three-dimensional (3-D) turbulence governed by the Navier-Stokes equations in fluid dynamics. This paper presents a new capability for simulating turbulence at a new record resolution up to 35 trillion grid points, on the world's first exascale computer, Frontier, comprising AMD MI250x GPUs with HPE's Slingshot interconnect and operated by the US Department of Energy's Oak Ridge Leadership Computing Facility (OLCF). Key programming strategies designed to take maximum advantage of the machine architecture involve performing almost all computations on the GPU which has the same memory capacity as the CPU, performing all-to-all communication among sets of parallel processes directly on the GPU, and targeting GPUs efficiently using OpenMP offloading for intensive number-crunching including 1-D Fast Fourier Transforms (FFT) performed using AMD ROCm library calls. With 99% of computing power on Frontier being on the GPU, leaving the CPU idle leads to a net performance gain via avoiding the overhead of data movement between host and device except when needed for some I/O purposes. Memory footprint including the size of communication buffers for MPI_ALLTOALL is managed carefully to maximize the largest problem size possible for a given node count.Detailed performance data including separate contributions from different categories of operations to the elapsed wall time per step are reported for five grid resolutions, from 20483 on a single node to 327683 on 4096 or 8192 nodes out of 9408 on the system. Both 1D and 2D domain decompositions which divide a 3D periodic domain into slabs and pencils respectively are implemented. The present code suite (labeled by the acronym GESTS, GPUs for Extreme Scale Turbulence Simulations) achieves a figure of merit (in grid points per second) exceeding goals set in the Center for Accelerated Application Readiness (CAAR) program for Frontier. The performance attained is highly favorable in both weak scaling and strong scaling, with notable departures only for 20483 where communication is entirely intra-node, and for 327683, where a challenge due to small message sizes does arise. Communication performance is addressed further using a lightweight test code that performs all-to-all communication in a manner matching the full turbulence simulation code. Performance at large problem sizes is affected by both small message size due to high node counts as well as dragonfly network topology features on the machine, but is consistent with official expectations of sustained performance on Frontier. Overall, although not perfect, the scalability achieved at the extreme problem size of 327683 (and up to 8192 nodes — which corresponds to hardware rated at just under 1 exaflop/sec of theoretical peak computational performance) is arguably better than the scalability observed using prior state-of-the-art algorithms on Frontier's predecessor machine (Summit) at OLCF. New science results for the study of intermittency in turbulence enabled by this code and its extensions are to be reported separately in the near future.

Strain-mediated reservoir computing with temporal and spatial co-multiplexing in multiferroic heterostructures

Physical reservoir computing (PRC), a brain-inspired computing method known for its efficient information processing and low training requirements, has attracted significant attention. The key factor lies in the number of computational nodes within the reservoir for its computational capability. Here, we explore co-multiplexing reservoirs that leverage both temporal and spatial strategies. Temporal multiplexing virtually expands the node count through the use of masking techniques, while spatial multiplexing utilizes multiple physical locations (e.g., Hall bars) to achieve an increase in the number of real nodes. Our experiment employs a strain-mediated reservoir based on multiferroic heterostructures. By applying a single voltage across the PMN-PT substrate (acting as global input) and measuring the output Hall voltages from four Hall bars (real nodes), we achieve significant efficiency gains. This co-multiplexing approach results in a reduction in the normalized root mean square error from 0.5 to 0.23 for a 20-step prediction task of a Mackey–Glass chaotic time series. Furthermore, the single input and four independent outputs lead to a fourfold reduction in energy consumption compared to the strain-mediated PRC with temporal multiplexing solely. This research paves the way for future energy saving PRC implementations utilizing co-multiplexing, promoting a resource-efficient paradigm in reservoir computing.

319. EXTENSIVE LYMPHADENECTOMY MAY IMPROVE SURVIVAL IN NODE NEGATIVE OESOPHAGEAL CANCER

Abstract Background Lymph node metastases are a major prognostic factor in survival of patients with oesophageal cancer. The number of lymph nodes removed during oesophagectomy has been previously proven to be associated with improved survival. The aim of this study was to examine the effect of lymph node harvest on survival specifically in pathologically node negative (pN0) patients with oesophageal cancer. Methods Data were extracted from a prospectively populated single-surgeon database of oesophageal resections for cancer. All consecutive patients with pN0 were included. Patient-specific risk adjusted analysis of overall and disease-free survival was performed to identify the number of lymph nodes associated with improved survival. Results Inclusion criteria were met by 137 patients (49 squamous cell carcinoma and 88 adenocarcinoma). Adjusted for cancer stage, tumour (histological type, degree of differentiation, lympho-vascular invasion, neo-adjuvant therapy) and patient related factors (age, sex), increased lymph node number was associated with significant improvement in overall (P = 0.045) and disease free (P = 0.030) survival. Lymph node count ≥ 17 was associated with improved overall and disease-free survival. Conclusion In this cohort of patients with pathologically node-negative oesophageal cancer, lymph node count of 17 or above was associated with significantly improved survival.

203. THE NUMBER OF RESECTED LYMPH NODES FROM THE UPPER MEDIASTINAL AREA PREDICTS LONG-TERM OUTCOMES OF ESOPHAGEAL CANCER AFTER MIE

Abstract Background The total number of resected lymph nodes (LNs) is an important determinant of longer survival after esophagectomy for esophageal squamous cell carcinoma (ESCC). However, resected LN counts from which areas affect long-term outcomes remain unclear. Methods: This study comprised 406 patients who underwent minimally invasive esophagectomy (MIE) at Kobe University Hospital. Resected LN counts were evaluated in the following areas: upper mediastinal (UM), middle mediastinal (MM), lower mediastinal (LM), and abdominal (Abd). Cut-off values for LN counts from each area were determined using receiver operating characteristics analysis to the survival status. Cox proportional hazards regression analyses were performed to identify prognostic factors. Results: The cut-off values for large or small numbers of resected LN counts in the UM, MM, LM, and Abd areas were 4, 8, 5, and 18 in patients with upper and middle thoracic (Ut/Mt) ESCC, respectively, and 7, 6, 5, and 24 in patients with lower thoracic (Lt) ESCC, respectively. Multivariate analysis in patients with Ut/Mt ESCC revealed that tumor invasion depth, lymph node metastasis and the resected LN count from the UM area were independent risk factors for overall survival (hazard ratio = 7.04; 95% confidence interval = 4.47-11.1, hazard ratio = 4.01; 95% confidence interval = 1.96-8.21, hazard ratio = 2.18; 95% confidence interval = 1.24-3.82, respectively). In patients with Lt ESCC, tumor invasion depth, lymph node metastasis and pulmonary complication were independent risk factors for overall survival (hazard ratio = 4.23; 95% confidence interval = 2.14-8.35, hazard ratio = 3.83; 95% confidence interval = 1.75-8.38, hazard ratio = 2.80; 95% confidence interval = 1.38-5.65, respectively). Resected LN counts from no areas were prognostic factors. Conclusions: The number of resected LNs from the UM area influenced survival outcomes of patients with Ut/Mt ESCC after MIE.

382. NUMBER OF LYMPH NODES RESECTED IS ASSOCIATED WITH OVERALL SURVIVAL IN PATHOLOGICALLY NODE-NEGATIVE ESOPHAGEAL CANCER

Abstract Background Lymphadenectomy is a key part of curative resection of esophageal cancer, with multiple quality assurance systems suggesting a minimum of 15 lymph nodes should be resected and subjected to pathological examination. Nevertheless, whether the absolute number of nodes resected is a surrogate marker for quality in surgery and staging, or has therapeutic benefit is debated. The aim of this study was to determine the impact of lymphadenectomy on survival in patients with resected pathologically node-negative disease (both treated and untreated with neoadjuvant therapy). Methods A review of our institutional prospectively maintained database was conducted from 2010-2020 inclusive. Inclusion criteria were patients undergoing esophagectomy for esophageal cancer aged 18+ who consented to data inclusion. Exclusion criteria were patients undergoing resection for benign disease, patients with Siewert III tumours undergoing gastrectomy or extended total gastrectomy, patients undergoing re-operative surgery, or patients where final pathology was not available. Univariable and multivariable analyses were performed as appropriate. Results 195 patients (49%) had pathologically node negative disease, with median lymph node count of 25. 47% of patients were clinically node positive, but pathologically node negative following neoadjuvant therapy. On univariable survival analysis, number of nodes resected was a significant predictor of overall survival (HR 0.96, 0.93-0.98, p=0.001). On multivariable analysis, R status (HR 4.9, 1.2-21.1, p=0.03), number of nodes resected (HR 0.97, 0.94-0.99, p=0.02) and prior cN+ status (HR 2.28, 1.16-4.49, p=0.02) were predictors of overall survival. Patients with cN0, (y)pN0 disease had improved overall survival compared with cN+, (y)pN0 (median not reached vs 43.4 months, p=0.04). Conclusion Lymphadenectomy is a key part of resection of esophageal cancer. In pathologically node negative patients, the extent of lymphadenectomy remains a key predictor of overall survival. Conversion from clinically node positive to pathologically node negative disease is associated with worse outcomes compared to clinically and pathologically node negative disease. Even in early stage cancer, a thorough, multi-field lymphadenectomy should be encouraged.

Endoscopic Resection of Stage T1 Colorectal Adenocarcinoma Followed by Surgical Intervention: a Single-center Retrospective Study

BackgroundDomestic and international guidelines recommend endoscopic resection for stage T1 colorectal adenocarcinoma with indications. However, completion surgery remains imperative for patients exhibiting high-risk factors subsequent to endoscopic procedures.ObjectiveTo investigate the evidence, pathological features, and surgical outcomes of completion surgery in patients with T1 colorectal adenocarcinoma following endoscopic resection.MethodsWe retrospectively collect data on the clinical features and treatment outcomes of patients with stage T1 colorectal adenocarcinoma who underwent endoscopic resection followed by surgical resection and those who initially completed surgical intervention at Peking University International Hospital between January 2019 and October 2022, with the aim of assessing the necessity and feasibility of surgical intervention.ResultsSeventeen patients (Group A) with high-risk factors following endoscopic procedure, especially with deep submucosal invasion and vascular or lymphatic invasion, experienced further surgical resection. The median interval between endoscopic resection and completion surgery was 23.71 days ± 15.89. Sixteen patients (Group B) underwent radical resection without any prior interventions. The surgical approach involves integration of laparoscopy and colonoscopy for precise localization and quantitative diagnosis, followed by radical surgery. The two groups demonstrated significant differences statistically with reference to tumor diameter (1.65 cm ± 0.77 vs 3.36 cm ± 1.39, P = 0.000) and the attainment of standard lymph node count (cases of detected lymph nodes larger than or equal to 12, 5 vs 12, P = 0.015). Postoperative complications and hospital stay manifested no significant disparity statistically in two groups. Patients who underwent completion surgery had no inferior outcomes compared with those who underwent direct surgery in terms of 5-year disease-free survival (Log rank test: P = 0.083, Breslow test: P = 0.089). The two groups also exhibited no significant differences statistically in the context of overall survival (Log rank test: P = 0.652, Breslow test: P = 0.758).ConclusionCompletion surgery is a safe and feasible treatment option for T1 colorectal adenocarcinoma patients with high-risk factors, particularly those with deep submucosal invasion and vascular or lymphatic invasion following endoscopic treatment. Furthermore, subsequent treatment should be chosen based on a comprehensive analysis of the patient’s history of abdominal surgery, willingness, and pathological features.

An Adaptive 3D Neighbor Discovery and Tracking Algorithm in Battlefield Flying Ad Hoc Networks with Directional Antennas.

Neighbor discovery and tracking with directional antennas in flying ad hoc networks (FANETs) is a challenging issue because of dispersed node distribution and irregular maneuvers in three-dimensional (3D) space. In this paper, we propose an adaptive 3D neighbor discovery and tracking algorithm in battlefield FANETs with directional antennas. With time synchronization, a flying node transmits/receives the neighbor discovery packets sequentially in each beam around it to execute a two-way handshake for neighbor discovery. The transmitting or receiving status of each discovery slot depends on the binary code corresponding to the identification of the node. Discovered neighbor nodes exchange their 3D positions in tracking slots periodically for node tracking, and the maximum tracking period is determined by node velocity, beamwidth, and the minimum distance between nodes. By configuring the relevant parameters, the proposed algorithm can also apply to two-dimensional planar ad hoc networks. The simulation results suggest that the proposed algorithm can achieve shorter neighbor discovery time and longer link survival time in comparison with the random scanning algorithm in scenarios with narrow beamwidth and wide moving area. When the frame length increases, the protocol overhead decreases but the average neighbor discovery time increases. The suitable frame length should be determined based on the network range, node count, beamwidth, and node mobility characteristics.