A Video-Based Procedure-Specific Competency Assessment Tool for Minimally Invasive Esophagectomy

Importance

Minimally invasive esophagectomy (MIE) is a complex procedure with substantial learning curves. In other complex minimally invasive procedures, suboptimal surgical performance has convincingly been associated with less favorable patient outcomes as assessed by peer review of the surgical procedure.

Objective

To develop and validate a procedure-specific competency assessment tool (CAT) for MIE.

Design, Setting, and Participants

In this international quality improvement study, a procedure-specific MIE-CAT was developed and validated. The MIE-CAT contains 8 procedural phases, and 4 quality components per phase are scored with a Likert scale ranging from 1 to 4. For evaluation of the MIE-CAT, intraoperative MIE videos performed by a single surgical team in the Esophageal Center East Netherlands were peer reviewed by 18 independent international MIE experts (with more than 120 MIEs performed). Each video was assessed by 2 or 3 blinded experts to evaluate feasibility, content validity, reliability, and construct validity. MIE-CAT version 2 was composed with refined content aimed at improving interrater reliability. A total of 32 full-length MIE videos from patients who underwent MIE between 2011 and 2020 were analyzed. Data were analyzed from January 2021 to January 2023.

Exposure

Performance assessment of transthoracic MIE with an intrathoracic anastomosis.

Main Outcomes and Measures

Feasibility, content validity, interrater and intrarater reliability, and construct validity, including correlations with both experience of the surgical team and clinical parameters, of the developed MIE-CAT.

Results

Experts found the MIE-CAT easy to understand and easy to use to grade surgical performance. The MIE-CAT demonstrated good intrarater reliability (range of intraclass correlation coefficients [ICCs], 0.807 [95% CI, 0.656 to 0.892] for quality component score to 0.898 [95% CI, 0.846 to 0.932] for phase score). Interrater reliability was moderate (range of ICCs, 0.536 [95% CI, -0.220 to 0.994] for total MIE-CAT score to 0.705 [95% CI, 0.473 to 0.846] for quality component score), and most discrepancies originated in the lymphadenectomy phases. Hypothesis testing for construct validity showed more than 75% of hypotheses correct: MIE-CAT performance scores correlated with experience of the surgical team (r = 0.288 to 0.622), blood loss (r = -0.034 to -0.545), operative time (r = -0.309 to -0.611), intraoperative complications (r = -0.052 to -0.319), and severe postoperative complications (r = -0.207 to -0.395). MIE-CAT version 2 increased usability. Interrater reliability improved but remained moderate (range of ICCs, 0.666 to 0.743), and most discrepancies between raters remained in the lymphadenectomy phases.

Conclusions and Relevance

The MIE-CAT was developed and its feasibility, content validity, reliability, and construct validity were demonstrated. By providing insight into surgical performance of MIE, the MIE-CAT might be used for clinical, training, and research purposes.

Concerted epithelial and stromal changes during progression of Barrett's Esophagus to invasive adenocarcinoma exposed by multi-scale, multi-omics analysis

Esophageal adenocarcinoma arises from Barrett's esophagus, a precancerous metaplastic replacement of squamous by columnar epithelium in response to chronic inflammation. Multi-omics profiling, integrating single-cell transcriptomics, extracellular matrix proteomics, tissue-mechanics and spatial proteomics of 64 samples from 12 patients' paths of progression from squamous epithelium through metaplasia, dysplasia to adenocarcinoma, revealed shared and patient-specific progression characteristics. The classic metaplastic replacement of epithelial cells was paralleled by metaplastic changes in stromal cells, ECM and tissue stiffness. Strikingly, this change in tissue state at metaplasia was already accompanied by appearance of fibroblasts with characteristics of carcinoma-associated fibroblasts and of an NK cell-associated immunosuppressive microenvironment. Thus, Barrett's esophagus progresses as a coordinated multi-component system, supporting treatment paradigms that go beyond targeting cancerous cells to incorporating stromal reprogramming.

Remoteness from urban centre does not affect gastric cancer outcomes with established care pathway to specialist centre

BACKGROUND

Patients living in rural communities experience difficulty accessing specialized medical care. Rural patients with cancer present with more advanced disease, have reduced access to treatment and have poorer overall survival than urban patients. This study's aim was to evaluate outcomes of patients with gastric cancer living in rural and remote areas versus urban and suburban communities in the context of an established care corridor to a tertiary care centre.

METHODS

All patients treated for gastric cancer at the McGill University Health Centre during 2010-2018 were included. Travel, lodging and cancer care coordination were provided for patients from remote and rural areas and coordinated centrally by dedicated nurse navigators servicing these regions. Statistics Canada's remoteness index was used to categorize patients into a rural and remote group and an urban and suburban group.

RESULTS

A total of 274 patients were included. Compared with patients from urban and suburban areas, patients from rural and remote areas were younger and their clinical tumour stage was higher at presentation. The number of curative resections and palliative surgeries and rate of nonresection were comparable (p = 0.96). Overall, disease-free and progression-free survival were comparable between the groups, and having locally advanced cancer correlated with poorer survival (p < 0.001).

CONCLUSION

Although patients with gastric cancer from rural and remote areas had more advanced disease at presentation, their treatment patterns and survival were comparable to those of patients from urbanized areas in the context of a publicly funded care corridor to a multidisciplinary specialist cancer centre. Equitable access to health care is necessary to diminish any preexisting disparities among patients with gastric cancer.

Relation between mismatch repair status, chemoresponse, survival and anatomic location in gastroesophageal adenocarcinoma

BACKGROUND

It has recently been reported that mismatch repair (MMR) status and microsatellite instability (MSI) status in gastroesophageal carcinomas predict surgical, chemotherapeutic and immunotherapeutic outcomes; however, there is extensive variability in the reported incidence and clinical implications of MMR/MSI status in gastroesophaegal adenocarcinomas. We characterized a Canadian surgical patient cohort with respect to MMR status, clinicopathologic correlates and anatomic tumour location.

METHODS

We investigated MMR and BRAF V600E status of gastroesophaegal adenocarcinomas in patients who underwent gastrectomy or esophagectomy with extended (D2) lymphadenectomy at a single centre between 2011 and 2019. We correlated patterns of MMR expression in the overall cohort and in anatomic location-defined subgroups with treatment response and overall survival using multivariate analysis.

RESULTS

In all, 226 cases of gastroesophaegal adenocarcinoma (63 esophageal, 98 gastroesophageal junctional and 65 gastric) were included. The MMR-deficient (dMMR) immunophenotype was found in 28 tumours (12.3%) (15 junctional [15.3%], 13 gastric [20.0%] and none of the esophageal). The majority (25 [89%]) of dMMR cases showed MLH1/PMS2 loss without concurrent BRAF V600E mutation. Two MSH2/ MSH6-deficient gastric tumours and 1 MSH6-deficient junctional tumour were detected. The pathologic response to preoperative chemotherapy was comparable in the dMMR and MMR-proficient (pMMR) cohorts. However, dMMR status was associated with significantly longer median overall survival than pMMR status (5.8 yr v. 2.4 yr, hazard ratio [HR] 1.91, 95% confidence interval [CI] 1.06-3.46), particularly in junctional tumours (4.6 yr v. 1.9 yr, HR 2.97, 95% CI 1.27-6.94).

CONCLUSION

Our study shows that MMR status has at least prognostic value, which supports the need for biomarker testing in gastroesophageal adenocarcinomas, including junctional adenocarcinomas. This highlights the clinical significance of determining the MMR status in all adenocarcinomas of the upper gastrointestinal tract. Response to induction chemotherapy, however, was not influenced by MMR status.

Abstract 2863: Cancer extracellular vesicles induce lymph node metastasis via neutrophil extracellular traps

In most human cancers, regional lymph nodes (LNs) are the first sites of metastasis. In addition to being an important part of the tumor staging system, with the advent of novel therapies, lymph node metastasis has become a crucial clinical intervention point before distant metastasis, the leading cause of cancer-associated deaths. To initiate metastasis, the conditions of LNs need to be optimized for tumor cell deposition and growth. This process is believed to be mediated by the activation of immune cells including polymorphonuclear neutrophils (PMNs), and tumor derived factors, such as extracellular vesicles (EVs). Indeed, tumor derived EVs (tEVs) were shown to prepare sentinel LNs for increased melanoma metastasis, however, the cellular mechanism is not well defined. Early observations suggest that PMNs and neutrophil extracellular traps (NETs), DNA comprising structures that are extruded in response to inflammatory cues, are associated with adverse oncologic outcomes. Moreover, PMNs exhibit considerable plasticity to tEVs, as gastric tEVs can polarize PMN toward a pro-tumor (N2) phenotype and induce NET formation. Thus, one potential mechanism of increased LN metastasis is that tEVs recruit PMNs and propend NETs formation. Here, we show that lymphatic PMN accumulation is associated with higher rates of LN metastasis in human esophageal cancer patients. Furthermore, we demonstrate that LN PMN accumulation is mediated by tEVs-lymphatic interaction both in vitro and in vivo. Finally, we demonstrate that lymphatic PMN facilitate metastasis through the accumulation of PMN prior to tumor ingress. Using Boyden chamber assays, we observed an increase in PMN migration towards tEVs educated lymphatic endothelial cells (LECs). Moreover, ELISA showed tEVs educated LEC increased secretion of the PMN chemoattractants CXCL4 and CXCL8. Additionally, through confocal microscopy and immunofluorescence, we observed that tEVs induced PMN recruitment to LNs and NETs released in vivo in a dose-dependent manner. Finally, using transgenic pad4-/- knockout mice, which are unable to generate NETs, we showed that the absence of NETs led to decreased LN metastasis. Together, these findings highlight the role of tumor derived tEVs both as PMN recruiters to LNs and NETs inducers. By further investigating the detailed mechanism and the efficiency of NETs targeting agents, this project will lead to major advances in the management of cancer patients.

Citation Format: Xin SU, Ariane Brassard, Ramin Rohanizadeh, Iqraa Dhoparee-Doomah, Betty Giannias, France Bourdeau, Veena Sangwan, Roni F. Rayes, Jonathan D. Spicer, Lorenzo E. Ferri, Jonathan J. Cools-Lartigue. Cancer extracellular vesicles induce lymph node metastasis via neutrophil extracellular traps [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2863.

Esophageal cancer after sleeve gastrectomy: a population-based comparative cohort study

BACKGROUND

Sleeve gastrectomy (SG) is the most common bariatric surgery; however, this approach may induce gastroesophageal reflux disease (GERD). Both obesity and GERD are independent risk factors for esophageal cancer, however the impact of SG on risk of esophageal cancer remains unknown.

OBJECTIVE

To evaluate the risk of esophageal cancer after reflux-prone bariatric surgery.

SETTING

Population-level, provincial administrative healthcare database, Quebec, Canada.

METHODS

We identified a population-based cohort of all patients with obesity who underwent reflux-prone surgery (SG and duodenal switch [DS]) or reflux-protective Roux-en-Y gastric bypass (RYGB) during 01/2006-12/2012 in Quebec, Canada. For every surgical patient, 2-3 nonsurgical controls with obesity matched for age, sex, and geography were also identified. Crude incidence rate ratios (IRRs) for esophageal cancer were calculated using person-time analysis. Hazard ratios (HRs) were obtained using multivariate cox regression.

RESULTS

A total of 4121 patients had reflux-prone procedures and 852 underwent RYGB. At a mean follow-up of 7.6 years, 8 cases of esophageal cancer were identified after bariatric surgery. Compared with RYGB, IRR for esophageal cancer in reflux-prone group was 1.45 (95%CI: .19-65.5) and HR = .83 (95%CI: .10-7.27). The crude incidence rate of esophageal cancer in the reflux-prone group was higher than that of nonsurgical controls (n = 12,159; IRR = 3.46, 95%CI: 1.00-12.5), but after adjustment the difference disappeared (HR = 2.47, 95%CI: .82-7.45).

CONCLUSIONS

Long-term incidence of esophageal cancer after reflux-prone bariatric surgery is not greater than RYGB. While crude incidence of esophageal cancer after reflux-prone surgery is higher than in nonsurgical patients with obesity, such difference disappears after accounting for confounders. Given the low incidence of esophageal cancer and slow progression of dysplastic Barrett esophagus, studies with longer follow-up are needed.

The Effect of Preoperative Anemia and Perioperative Transfusion on Surgical Outcomes After Gastrectomy for Gastric Cancer

BACKGROUND

The aim of this study is to examine the interaction between preoperative anemia and perioperative transfusions with postoperative morbidity and mortality among patients undergoing gastrectomy for cancer.

MATERIALS AND METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried from 2005 to 2016. Restricted cubic splines modeled the nonlinear relationship between preoperative hematocrit (Hct) and 30-day overall morbidity, sepsis, and mortality. Preoperative Hct was categorized based on cut points for the three models. Multiple regression modeling examined the interactive effect of preoperative anemia and postoperative transfusion on surgical outcomes.

RESULTS

Among 9936 included patients, complication incidence was 38.9% (sepsis 12.7%; mortality 6.0%). Preoperative Hct cut points were identified at 29 and 42. Hct <29 was associated with higher risk of morbidity (OR 2.47, 95%CI 2.10-2.93). Postoperative transfusion was associated with lower risk of morbidity for Hct <29 (OR 0.56, 95%CI 0.43-0.73) but increased risk between 29 and 42 (OR 1.59, 95%CI 1.21-2.08). Similar relationships were found for sepsis and mortality.

CONCLUSIONS

Preoperative Hct <29 is associated with an increased risk of surgical complications after gastrectomy for cancer and perioperative transfusions appear to be beneficial for Hct <29 only. There may be a role for better optimization of red cell mass among high-risk patients before gastrectomy for cancer.

Model-based analysis of sample index hopping reveals its widespread artifacts in multiplexed single-cell RNA-sequencing

Index hopping is the main cause of incorrect sample assignment of sequencing reads in multiplexed pooled libraries. We introduce a statistical model for estimating the sample index-hopping rate in multiplexed droplet-based single-cell RNA-seq data and for probabilistic inference of the true sample of origin of hopped reads. We analyze several datasets and estimate the sample index hopping probability to range between 0.003–0.009, a small number that counter-intuitively gives rise to a large fraction of phantom molecules — the fraction of phantom molecules exceeds 8% in more than 25% of samples and reaches as high as 85% in low-complexity samples. Phantom molecules lead to widespread complications in downstream analyses, including transcriptome mixing across cells, emergence of phantom copies of cells from other samples, and misclassification of empty droplets as cells. We demonstrate that our approach can correct for these artifacts by accurately purging the majority of phantom molecules from the data.

Sample index hopping results in various artefacts in multiplexed scRNA-seq experiments. Here, the authors introduce a statistical model to estimate sample index hopping rate in droplet-based scRNA-seq data and show that artifacts can be corrected by purging phantom molecules from the data.

Neutrophil Extracellular Trap-Associated CEACAM1 as a Putative Therapeutic Target to Prevent Metastatic Progression of Colon Carcinoma

Neutrophils promote tumor growth and metastasis at multiple stages of cancer progression. One mechanism through which this occurs is via release of neutrophil extracellular traps (NETs). We have previously shown that NETs trap tumor cells in both the liver and the lung, increasing their adhesion and metastasis following postoperative complications. Multiple studies have since shown that NETs play a role in tumor progression and metastasis. NETs are composed of nuclear DNA-derived web-like structures decorated with neutrophil-derived proteins. However, it is unknown which, if any, of these NET-affiliated proteins is responsible for inducing the metastatic phenotype. In this study, we identify the NET-associated carcinoembryonic Ag cell adhesion molecule 1 (CEACAM1) as an essential element for this interaction. Indeed, blocking CEACAM1 on NETs, or knocking it out in a murine model, leads to a significant decrease in colon carcinoma cell adhesion, migration and metastasis. Thus, this work identifies NET-associated CEACAM1 as a putative therapeutic target to prevent the metastatic progression of colon carcinoma.

Toll-like receptors: exploring their potential connection with post-operative infectious complications and cancer recurrence

Cancer is the leading cause of death in North America. Despite modern advances in cancer therapy, many patients will ultimately develop cancer metastasis resulting in mortality. Surgery to resect early stage solid malignancies remains the cornerstone of cancer treatment. However, surgery places patients at risk of developing post-operative infectious complications that are linked to earlier cancer metastatic recurrence and cancer mortality. Toll-like receptors (TLRs) are evolutionarily-conserved sentinel receptors of the innate immune system that are activated by microbial products present during infection, leading to activation of innate immunity. Numerous types of solid cancer cells also express TLRs, with their activation augmenting their ability to metastasize. Similarly, healthy host-tissue TLRs activated during infection induce a prometastatic environment in the host. Cancer cells additionally secrete TLR activating ligands that activate both cancer TLRs and host TLRs to promote metastasis. Consequently, TLRs are an attractive therapeutic candidate to target infection-induced cancer metastasis and progression.

Activation of the pattern recognition receptor NOD1 augments colon cancer metastasis

While emerging data suggest nucleotide oligomerization domain receptor 1 (NOD1), a cytoplasmic pattern recognition receptor, may play an important and complementary role in the immune response to bacterial infection, its role in cancer metastasis is entirely unknown. Hence, we sought to determine the effects of NOD1 on metastasis. NOD1 expression in paired human primary colon cancer, human and murine colon cancer cells were determined using immunohistochemistry and immunoblotting (WB). Clinical significance of NOD1 was assessed using TCGA survival data. A series of in vitro and in vivo functional assays, including adhesion, migration, and metastasis, was conducted to assess the effect of NOD1. C12-iE-DAP, a highly selective NOD1 ligand derived from gram-negative bacteria, was used to activate NOD1. ML130, a specific NOD1 inhibitor, was used to block C12-iE-DAP stimulation. Stable knockdown (KD) of NOD1 in human colon cancer cells (HT29) was constructed with shRNA lentiviral transduction and the functional assays were thus repeated. Lastly, the predominant signaling pathway of NOD1-activation was identified using WB and functional assays in the presence of specific kinase inhibitors. Our data demonstrate that NOD1 is highly expressed in human colorectal cancer (CRC) and human and murine CRC cell lines. Clinically, we demonstrate that this increased NOD1 expression negatively impacts survival in patients with CRC. Subsequently, we identify NOD1 activation by C12-iE-DAP augments CRC cell adhesion, migration and metastasis. These effects are predominantly mediated via the p38 mitogen activated protein kinase (MAPK) pathway. This is the first study implicating NOD1 in cancer metastasis, and thus identifying this receptor as a putative therapeutic target.

Diagnostic criteria and symptom grading for delayed gastric conduit emptying after esophagectomy for cancer: international expert consensus based on a modified Delphi process

Delayed gastric conduit emptying (DGCE) after esophagectomy for cancer is associated with adverse outcomes and troubling symptoms. Widely accepted diagnostic criteria and a symptom grading tool for DGCE are missing. This hampers the interpretation and comparison of studies. A modified Delphi process, using repeated web-based questionnaires, combined with live interim group discussions was conducted by 33 experts within the field, from Europe, North America, and Asia. DGCE was divided into early DGCE if present within 14 days of surgery and late if present later than 14 days after surgery. The final criteria for early DGCE, accepted by 25 of 27 (93%) experts, were as follows: >500 mL diurnal nasogastric tube output measured on the morning of postoperative day 5 or later or >100% increased gastric tube width on frontal chest x-ray projection together with the presence of an air-fluid level. The final criteria for late DGCE accepted by 89% of the experts were as follows: the patient should have 'quite a bit' or 'very much' of at least two of the following symptoms; early satiety/fullness, vomiting, nausea, regurgitation or inability to meet caloric need by oral intake and delayed contrast passage on upper gastrointestinal water-soluble contrast radiogram or on timed barium swallow. A symptom grading tool for late DGCE was constructed grading each symptom as: 'not at all', 'a little', 'quite a bit', or 'very much', generating 0, 1, 2, or 3 points, respectively. For the five symptoms retained in the diagnostic criteria for late DGCE, the minimum score would be 0, and the maximum score would be 15. The final symptom grading tool for late DGCE was accepted by 27 of 31 (87%) experts. For the first time, diagnostic criteria for early and late DGCE and a symptom grading tool for late DGCE are available, based on an international expert consensus process.

Effect of Exercise and Nutrition Prehabilitation on Functional Capacity in Esophagogastric Cancer Surgery: A Randomized Clinical Trial

Importance

Preserving functional capacity is a key element in the care continuum for patients with esophagogastric cancer. Prehabilitation, a preoperative conditioning intervention aiming to optimize physical status, has not been tested in upper gastrointestinal surgery to date.

Objective

To investigate whether prehabilitation is effective in improving functional status in patients undergoing esophagogastric cancer resection.

Design, Setting, and Participants

A randomized clinical trial (available-case analysis based on completed assessments) was conducted at McGill University Health Centre (Montreal, Quebec, Canada) comparing prehabilitation with a control group. Intervention consisted of preoperative exercise and nutrition optimization. Participants were adults awaiting elective esophagogastric resection for cancer. The study dates were February 13, 2013, to February 10, 2017.

Main Outcomes and Measures

The primary outcome was change in functional capacity, measured with absolute change in 6-minute walk distance (6MWD). Preoperative (end of the prehabilitation period) and postoperative (from 4 to 8 weeks after surgery) data were compared between groups.

Results

Sixty-eight patients were randomized, and 51 were included in the primary analysis. The control group were a mean (SD) age, 68.0 (11.6) years and 20 (80%) men. Patients in the prehabilitation group were a mean (SD) age, 67.3 (7.4) years and 18 (69%) men. Compared with the control group, the prehabilitation group had improved functional capacity both before surgery (mean [SD] 6MWD change, 36.9 [51.4] vs -22.8 [52.5] m; P < .001) and after surgery (mean [SD] 6MWD change, 15.4 [65.6] vs -81.8 [87.0] m; P < .001).

Conclusions and Relevance

Prehabilitation improves perioperative functional capacity in esophagogastric surgery. Keeping patients from physical and nutritional status decline could have a significant effect on the cancer care continuum.

Trial Registration

ClinicalTrials.gov Identifier: NCT01666158.

Comparison of Dor and Nissen fundoplication after laparoscopic paraesophageal hernia repair

BACKGROUND

Fundoplication is performed routinely during laparoscopic repairs of a paraesophageal hernia, but the degree of fundoplication remains controversial. The purpose of this study is to assess postoperative dysphagia and reflux after a Dor versus a Nissen fundoplication in patients undergoing laparoscopic repair of giant paraesophageal hernias.

METHODS

We performed a retrospective cohort study of all patients undergoing laparoscopic repair of giant paraesophageal hernias with Nissen or Dor fundoplication between January 2012 and December 2017 at a high-volume center, excluding revisional and emergency cases. Primary outcomes were reflux and dysphagia at 1 and 6 months. Severe dysphagia was defined as intolerance to liquids. Balanced cohorts were created using coarsened exact matching.

RESULTS

A total of 106 patients were included, and 87 were matched (Dor = 48, Nissen = 58). Baseline characteristics were well balanced between matched groups. Mean follow-up duration was 17.7 months (standard deviation 16.4). The incidence of severe dysphagia at 1 month was less in the Dor group (0 of 48 vs 8 of 58, P = .02) with similar reflux symptoms. There was no difference in severe dysphagia and reflux symptoms at 6 months and at the latest visit.

CONCLUSION

Dor fundoplication is associated with less severe, early postoperative dysphagia. Future studies assessing the relative importance of dysphagia and reflux on quality of life should be conducted to tailor the operative technique and optimize patient satisfaction.

Gram-Negative Pneumonia Augments Non-Small Cell Lung Cancer Metastasis through Host Toll-like Receptor 4 Activation

INTRODUCTION

Surgery is essential for cure of early-stage non-small cell lung cancer (NSCLC). Rates of postoperative bacterial pneumonias, however, remain high, and clinical data suggests that post-operative infectious complications confer an increased risk for metastasis. Toll-like receptors (TLRs) mediate the inflammatory response to infection by recognizing evolutionarily conserved bacterial structures at the surface of numerous pulmonary cell types; yet, little is known about how host TLR activation influences NSCLC metastasis. TLR4 recognizes gram-negative bacterium lipopolysaccharide activating the innate immune system.

METHODS

C57BL/6 and TLR4 knockout murine airways were inoculated with Escherichia coli or lipopolysaccharide. Hepatic metastasis assays and intravital microscopy were performed. Bronchoepithelial conditioned media was generated through coincubation of bronchoepithelial cells with TLR4 activating Escherichia coli or lipopolysaccharide. Subsequently, H59 NSCLC were stimulated with conditioned media and subject to various adhesion assays.

RESULTS

We demonstrate that gram-negative Escherichia coli pneumonia augments the formation of murine H59 NSCLC liver metastases in C57BL/6 mice through TLR4 activation. Additionally, infected C57BL/6 mice demonstrate increased H59 NSCLC in vivo hepatic sinusoidal adhesion compared with negative controls, a response that is significantly diminished in TLR4 knockout mice. Similarly, intratracheal injection of purified TLR4 activating lipopolysaccharide increases in vivo adhesion of H59 cells to murine hepatic sinusoids. Furthermore, H59 cells incubated with bronchoepithelial conditioned medium show increased cell adhesion to in vitro extracellular matrix proteins and in vivo hepatic sinusoids through a mechanism dependent on bronchoepithelial TLR4 activation and interleukin-6 secretion.

CONCLUSION

TLR4 is a viable therapeutic target for NSCLC metastasis augmented by gram-negative pneumonia.

Primary tumors induce neutrophil extracellular traps with targetable metastasis promoting effects

Targeting the dynamic tumor immune microenvironment (TIME) can provide effective therapeutic strategies for cancer. Neutrophils are the predominant leukocyte population in mice and humans, and mounting evidence implicates these cells during tumor growth and metastasis. Neutrophil extracellular traps (NETs) are networks of extracellular neutrophil DNA fibers that are capable of binding tumor cells to support metastatic progression. Here we demonstrate for the first time that circulating NET levels are elevated in advanced esophageal, gastric and lung cancer patients compared to healthy controls. Using pre-clinical murine models of lung and colon cancer in combination with intravital video microscopy, we show that NETs functionally regulate disease progression and that blocking NETosis through multiple strategies significantly inhibits spontaneous metastasis to the lung and liver. Further, we visualize how inhibiting tumor-induced NETs decreases cancer cell adhesion to liver sinusoids following intrasplenic injection - a mechanism previously thought to be driven primarily by exogenous stimuli. Thus, in addition to neutrophil abundance, the functional contribution of NETosis within the TIME has critical translational relevance and represents a promising target to impede metastatic dissemination.

Abstract 2799: Targeting CXCR2-mediated neutrophil recruitment to lung cancer

With recent advances in immunotherapy, it is evident that targeting the tumor microenvironment (TME) is an effective strategy to treat lung cancer (LC), however, more than half LC patients are still resistant to therapy. Limited attention was given to the relevance of the innate immune system despite its critical role in triggering adaptive responses. Neutrophils (PMNs) are the predominant circulating leukocyte in humans. PMNs are associated with developing lesions and are the main immune component of primary non-small cell LC (NSCLC). Multiple studies support the notion that PMNs promote tumor progression, however, the exact mechanisms in which these PMNs are recruited to the primary and metastatic lung TMEs remain unclear. To this end, we examined available genomic databases of &gt; 1,000 NSCLC primary adenocarcinoma (ADC) patients and observed that high expression of all CXCR2 ligands (CXCL1-8 and MIF) correlate with poor survival in lung ADC. Lung ADC patients display one of the highest fold increases of these ligands as compared to all other cancers. We then performed shRNA knock down (KD) of CXCL1 and MIF in A549 and tested the migration of PMNs towards treated and control cell lines using the novel microfluidic device. We observe 3-fold increase of PMN migration towards A549 compared to control. This increase was significantly inhibited in MIF and CXCL1 KDs as well as using MIF and CXCL1 neutralizing antibodies (NA) as compared to controls. PMN migration was higher to A549 then to PC9EN, and treatment of PMNs with a CXCR2 NA led to a decrease in their migration to A549 while unaffecting their migration to PC9EN. Due to the lack of similar genomic databases on LC metastasis, we profiled liver homogenates of mice intrasplenically injected with liver-metastatic Lewis lung carcinoma (LLC) and observed that Cxcl1 was the most overexpressed gene as compared to non-tumor bearing mice (non-TBM). We then KD CXCL1 from the liver metastatic LLC cell line and compared its capacity to recruit PMNs in live mice using intravital microscopy. We observe a decrease in the number of PMNs around developing CXCL1 KD LLC tumors compared to control LLC. We also observe a decrease in PMN migration toward the CXCL1 KD LLC tumors as compared the control LLC. This resulted in a significant decrease in liver metastasis of the CXCL1 KD LLC as compared to control LLC injected mice. Altogether, our data highlight the importance of CXCR2-mediated PMN migration in primary LC and the establishment of liver metastasis from LC. Thus, inhibiting CXCR2 represents a promising strategy to impede primary tumor growth and metastatic dissemination of LC.

Citation Format: Roni F. Rayes, Jack G. Mouhanna, Claire Wang, Simon Milette, Carson Wong, Mariana Usatii, Betty Giannias, France Bourdeau, Rachel Mot, Arvind Chandrasekaran, Christopher Moraes, Sidong Huang, Daniela Quail, Logan Walsh, Veena Sangwan, Nicholas Bertos, Pierre-Olivier Fiset, Jonathan Cools-Lartigue, Lorenzo E. Ferri, Jonathan D. Spicer. Targeting CXCR2-mediated neutrophil recruitment to lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2799.

Abstract 1508: Primary tumors induce neutrophil extracellular traps with targetable metastasis promoting effects

Targeting the dynamic tumor immune microenvironment can provide effective therapeutic strategies for cancer. Neutrophils (polymorphonuclear neutrophils, PMNs) are the predominant circulating leukocyte population in humans and are vital to fight infection. Despite mounting evidence that PMNs can promote tumor progression, depleting PMNs is not a viable therapeutic option. Neutrophil extracellular traps (NETs) are networks of extracellular neutrophil DNA fibers that are capable of trapping tumor cells and promoting their growth and their metastasis. Targeting NETs can therefore be a potentially successful therapeutic option to block the tumor promoting functions of PMNs. Here we demonstrate that circulating NET levels are elevated in esophageal, gastric and lung cancer patients compared to healthy controls. This increase correlates with disease stage and NET levels are independent predictors of advanced stage. Using pre-clinical murine models of lung and colon cancer, we observe elevated NET levels in tumor bearing mice compared to non-tumor bearing mice; these levels correlated with tumor size. NET levels significantly decrease following tumor resection or treatment with DNase1, a NET degrader, or neutrophil elastase inhibitor (NEi), a NET inhibitor. NET levels do not rise following tumor inoculation in peptidyl arginine deiminase-IV knock out (PAD4-/-) mice; PAD4 being an enzyme essential for citrullination of histones, a crucial step in NET release. Moreover, PMNs from tumor bearing mice are more primed for NETosis than PMNs from non-tumor bearing mice or NEi-treated or PAD4-/- tumor bearing mice. Finally, elevated in vivo hepatic adhesion and spontaneous liver and lung metastases are observed in tumor bearing mice compared to DNase1- or NEi-treated or PAD4-/- tumor bearing mice. Therefore, inhibiting NETs represents a promising strategy to impede metastatic dissemination in several types of cancer patients.

Citation Format: Roni F. Rayes, Jack G. Mouhanna, Ioana Nicolau, Phil Vourtzoumis, Carson Wong, Jules Eustache, France Bourdeau, Betty Giannias, Aya Siblini, Emma Lee, Veena Sangwan, Simon Rousseau, Daniela Quail, Logan Walsh, Nicholas Bertos, Jonathan Cools-Lartigue, Lorenzo E. Ferri, Jonathan D. Spicer. Primary tumors induce neutrophil extracellular traps with targetable metastasis promoting effects [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1508.

Sentinel Lymph Node Sampling for Early Gastric Cancer-Preliminary Results of A North American Prospective Study

INTRODUCTION

Although endoscopic resection for early gastric cancer is well established, anatomical resection with regional lymphadenectomy is recommended for lesions at high risk for occult lymph node metastasis (e.g., lymphovascular invasion, poor grade, and deep submucosal invasion). However, 75-95% high-risk early gastric cancer (HR-EGC) patients ultimately have node-negative disease and could potentially have undergone organ-sparing resection. Due to the inadequacy of standard modalities to reliably rule out nodal metastases in HR-EGC patients, sentinel lymph node (SLN) sampling was developed in Asia with promising results. However, the applicability of this technique in the West has been brought into question due to potential differences in tumor histology and body habitus. This prospective study aimed to test SLN sampling for North American EGC patients.

METHODS

All patients with biopsy-confirmed T0-2 N0-1 M0 gastric adenocarcinoma at the Montreal General Hospital-McGill University Health Centre were eligible for enrollment. Esophageal and GEJ cancers were excluded due to the high rate of intrathoracic lymph node involvement. Peritumoral submucosal injection with T⁹⁹ radiocolloid was performed endoscopically 24-30 h prior to surgery. Methylene blue dye injection was performed after induction of anesthesia. SLN basins were identified as those having > 10% of baseline tumor radiation signal or blue color, or both. After basins were individually removed, standard laparoscopic anatomical resection was then performed with D2 lymphadenectomy. ( ClinicalTrials.gov identifier: NCT03049345). Data are presented as median (interquartile range).

RESULTS

From July 2016-April 2018, 253 patients with esophagogastric adenocarcinoma were evaluated. Of these, 10 met inclusion criteria (90% male, age 66(30) years). Subtotal gastrectomy was performed in nine patients (90%) and length of stay was 4 (2) days. At least one SLN basin was identified in nine cases (90%). The median #SLN basins identified was 2(2) with a median of 5(5) total SLNs retrieved per patient. In the one case for which no SLN basins were identified, only blue dye injection was used, whereas SLNs were identified in all cases using the dual tracer method. Final T-stage was pT1b/T2 in four (40%), pT1a in two (20%), and Tx in four (40%). Two patients (20%) had lymph node metastases on final pathological analysis, both of which were identified by SLN sampling (accuracy 100%; false negative rate 0%). No adverse events related to SLN retrieval were identified.

CONCLUSIONS

This study represents the first prospective feasibility evaluation of sentinel lymph node sampling for early gastric cancer in North America with promising preliminary results. The dual tracer method was superior to single agent blue dye in identifying sentinel nodal basins. Considerable further study is necessary to verify the safety and utility of SLN mapping in North American patients with early gastric adenocarcinoma.

Multivisceral Resection for Locally Advanced Gastric and Gastroesophageal Junction Cancers-11-Year Experience at a High-Volume North American Center

INTRODUCTION

The oncologic benefit of multivisceral en bloc resections for T4 gastroesophageal tumors has been questioned, given the increased morbidity associated. We thus sought to investigate the surgical and oncologic outcomes of curative-intent en bloc multivisceral resections for T4 gastroesophageal carcinomas.

METHODS

Between 2005 and 2016, 35 of the 525 patients who had gastric or EGJ carcinomas underwent curative-intent multivisceral resections for direct invasion or adhesion to adjacent organs.

RESULTS

Postoperative complications occurred in 16(46%), 10 of which were Clavien-Dindo ≥ 3 (29%). Ninety-day mortality was 3%. The R0 resection rate was 94% (33). Direct organ invasion (pT4b) was confirmed on pathological analysis in 14 (40%) and did not affect survival. The majority (28, 80%) had lymph node involvement with a high nodal disease burden and was associated with decreased survival. Overall 5-year survival rate was 34%, and the vast majority of recurrences were distant/peritoneal (81%). On multivariate analysis, positive lymph nodes (H.R. 21.2; 95%CI 2.34-192) and R1 resection (H.R. 5.6; 95%CI 1.02-30.9) were predictors of survival.

CONCLUSION

Multivisceral resections for T4 gastric and GEJ adenocarcinomas, in combination with effective systemic therapy, result in prolonged long-term survival with acceptable morbidity. Complete resection to negative margins should remain a mainstay of curative-intent treatment in carefully selected patients.

Enhanced recovery after pulmonary surgery

The concept of surgical recovery encompasses the entire perioperative phase of the patient, beginning with the preoperative baseline and culminating in the long-term rehabilitation of the patient in the post-operative phase. Enhanced recovery pathways (ERPs) aim to encompass all phase of the patient trajectory, including the preoperative, perioperative, and postoperative management of surgical patients. While significant literature exists on standardizing and optimizing the perioperative phase, standardizing the pre and post-operative phases remains a topic of debate. Furthermore, with regards to pulmonary surgery, the available data on enhanced recovery remains limited, with no consensus on which components to include within the ERP. The difficulty in identifying specific factors to include within a pathway is in part due to the lack of representative metrics of recovery. Secondly, the strength of ERPs usually lies in the agglomeration of multiple components rather than the individual components themselves. This review provides a brief review on current developments in ERPs in pulmonary surgery, emphasizing novel components in the pre and post-operative care of patients. Furthermore, we discuss the limitations of current metrics used to study recovery, and what steps can be taken to direct future studies that aim to enhance patient recovery after pulmonary surgery.

Abstract 5176: Cell free malignant ascites fluid facilitates gastric adenocarcinoma peritoneal metastasis

Gastric adenocarcinoma is the fastest rising malignancy in North America. It is commonly associated with malignant ascites (MA), the pathological accumulation of fluid containing cancer cells in the peritoneum. Peritoneal metastasis is the most common site of gastric cancer (GC) progression after curative intent surgery and is the leading cause of death. Upon peritoneal dissemination, the malignant process is deemed non-curative as it is rarely amenable to surgical resection and chemotherapeutic regimens are simply palliative. We hypothesize that cell-free MA increases the potential of GC cells to worsen peritoneal metastasis. Gastric adenocarcinoma cell lines (human: MKN-45, SNU-5, KATO III, OKAJIMA; murine NCC-S1, NCC-S1M) were incubated with cell-free MA and their metastatic ability assessed with static in vitro adhesion assays, as well as migration assays. A novel ex vivo peritoneal metastasis model further corroborated the in vitro results, where cancer cell adhesion to stripped human peritoneum was assessed by co-incubation with non- and pre-stimulated cancer cells. Gross liver metastasis was monitored over several weeks after in vivo intra-peritoneal and intra-splenic injections, whereby C57BL/6 mice were inoculated with control media or stimulated NCC-S1M cells. Incubation of human GC cells and/or human peritoneal mesothelial cells (HPMC) with cell-free MA resulted in a significant three to five-fold increase of GC cell adhesion to HPMC compared to non-stimulated condition (P&lt;0.05), as measured by inverted fluorescent microscopy. In addition, the murine GC cells incubated with MA showed a significant eight-fold increase on average (P&lt;0.05) in GC cell adhesion to HPMC compared to non-stimulated condition. Cell-free MA was shown to significantly enhance ex vivo SNU-5 cell adhesion to stripped human peritoneum by a two to four-fold increase (P&lt;0.05) compared to non-stimulated condition. Liver metastases were visible in mice that received in vivo injections of ascites-stimulated NCC-S1M cancer cells by day 25, yet not in mice inoculated with control media. Several factors (ANG-2, HGF, ICAM-1, IL-8, TIMP-2, uPAR, VEGF, NAP-2, MIF) were shown to be upregulated in MA samples compared to a cirrhotic ascites control, using a multiplex ELISA. In particular, VEGF was upregulated 11 to 25-fold, and MIF two to 12-fold. The results demonstrated that MA plays a significant role in facilitating GC cell adhesion to peritoneal mesothelia, an important early step in the peritoneal metastatic cascade. MA must therefore provide an environment that supports tumour growth and spread. A more comprehensive understanding of the molecular network is essential to determine the role of cell free MA fluid in GC progression, allowing for the identification of potential therapeutic targets for this aggressive malignancy.

Citation Format: Chantelle A. Janeiro, Vivian Stavrakos, Malak Alzahrani, Roni F. Rayes, France Bourdeau, Betty Giannias, Nicholas Bertos, Veena Sangwan, Jonathan Cools-Lartigue, Jonathan D. Spicer, Lorenzo E. Ferri. Cell free malignant ascites fluid facilitates gastric adenocarcinoma peritoneal metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5176.

Same day discharge for benign laparoscopic hiatal surgery: a feasibility analysis

BACKGROUND

Advances in minimally invasive surgery and the development of enhanced recovery pathways have favored the spread of day-surgery programs. Despite laparoscopic approaches being accepted as the standard of care for benign hiatal diseases, safety and feasibility of same day discharges for laparoscopic hiatal surgeries other than fundoplication has yet to be established.

OBJECTIVE

This study aimed to assess the feasibility of same day discharge for primary and revisional laparoscopic hiatal surgeries including paraesophageal hernia repairs (PEHR), fundoplication for reflux, and Heller myotomy (±diverticulectomy).

METHODS

A retrospective cohort study including all patients undergoing elective laparoscopic hiatal procedures in the division of Thoracic surgery between 2011 and 2016 at McGill University Health Centre was performed. Planned day-surgery (DAYCASE) was compared to planned inpatient (INPATIENT) cohorts with respect to operative and postoperative outcomes, length of stay, readmission, and emergency room visits.

RESULTS

A total of 261 patients were identified, 161 female (62%); median age 62 (20). The case distribution was: PEHR (123; 47.1%), Heller myotomy (94;36%, 7 diverticulectomy), and fundoplication (44; 16.9%). Twenty patients had revisional procedures (7.7%). Same day discharge was planned in 98 cases (38%) and was successful in 80 (81.6%). Proportion of DAYCASE increased form 12% prior to 2013 to 67% in 2016. INPATIENTs were older (median 66 vs. 60 years), and had a higher proportion of PEHR (55 vs. 34%), p < 0.05. Both cohorts were comparable in gender proportion, ASA classification, and length of surgery. Complications, readmission, and emergency visits did not differ between the two cohorts. On multivariate analysis, female gender (OR 37, 95% CI 1.46-936, p = 0.028), surgery beginning after noon (OR 5.4, 95% CI 1.1-26.9, p = 0.038), intraoperative complications (OR 20.4 95% CI 1.5-286, p = 0.025), and postoperative complications (OR 52.1, 95% CI 4.5-602, p = 0.002) were independently associated with unplanned admission.

CONCLUSIONS

Day-case surgery for complex laparoscopic hiatal procedures is feasible and can be achieved in a significant number of patients without compromising safety.

Economic Impact of an Enhanced Recovery Pathway for Lung Resection

BACKGROUND

Multimodal enhanced recovery pathways (ERP) improve clinical outcomes and hospital length of stay for patients undergoing lung resection. However, data supporting their economic impact is lacking. This study evaluated the effect of an ERP on costs of lung resection.

METHODS

Adult patients undergoing elective lung resection from August 2011 to August 2013 at a single university-affiliated institution were prospectively recruited. Pneumonectomies and extended resections were excluded. Beginning in September 2012, patients were enrolled in a multimodal ERP. Outcomes were recorded until 90 days after discharge. Total costs from institutional, health care system, and societal perspectives are reported in 2016 Canadian dollars, with uncertainty expressed as 95% confidence intervals derived using bootstrapped estimates (10,000 repetitions).

RESULTS

The study included 133 patients (conventional care: n = 58; ERP: n = 75). Patient and operative characteristics were similar between the groups. The ERP group had shorter median (interquartile range) length of stay (4 [3 to 6] days vs 6 [4 to 9] days, p < 0.01), decreased total complications (32% vs 52%, p = 0.02), and decreased pulmonary complications (16% vs 34%, p = 0.01), with no difference in readmissions. After discharge, there was a trend towards less caregiver burden for the ERP group (53 ± 90 hours vs 101 ± 252 hours, p = 0.17). Overall societal costs were lower in the ERP group (mean difference per patient: -$4,396 Canadian; 95% confidence interval -$8,674 to $618 Canadian).

CONCLUSIONS

A multidisciplinary ERP is associated with improved clinical outcomes and societal cost savings compared with conventional perioperative management for elective lung resection.

Gram-positive pneumonia augments non-small cell lung cancer metastasis via host toll-like receptor 2 activation

Surgical resection of early stage nonsmall cell lung cancer (NSCLC) is necessary for cure. However, rates of postoperative bacterial pneumonias remain high and may confer an increased risk for metastasis. Toll-like receptors (TLRs) mediate the inflammatory cascade by recognizing microbial products at the surface of numerous cell types in the lung; however, little is known about how host TLRs influence NSCLC metastasis. TLR2 recognizes gram-positive bacterial cell wall components activating innate immunity. We demonstrate that lower respiratory tract infection with Streptococcus pneumonia augments the formation of murine H59 NSCLC liver metastases in C57BL/6 mice through host TLR2 activation. Infected mice demonstrate increased H59 and human A549 NSCLC adhesion to hepatic sinusoids in vivo compared with noninfected controls, a response that is significantly diminished in TLR2 knock-out mice. Intra-tracheal injection of purified TLR2 ligand lipoteichoic acid into mice similarly augments in vivo adhesion of H59 cells to hepatic sinusoids. Additionally, H59 and A549 NSCLC cells incubated with bronchoepithelial conditioned media show increased cell adhesion to extracellular matrix components in vitro and hepatic sinusoids in vivo in a manner that is dependent on bronchoepithelial TLR2 activation and interleukin-6 secretion. TLR2 is therefore a potential therapeutic target for gram-positive pneumonia-driven NSCLC metastasis.

Neutrophil extracellular traps sequester circulating tumor cells via β1-integrin mediated interactions

Despite advances in cancer treatment, metastasis remains today the main cause of cancer death. Local control through complete surgical resection of the primary tumor continues to be a key principle in cancer treatment. However, surgical interventions themselves lead to adverse oncologic outcomes and are associated with significantly increased rates of metastasis. Neutrophils through release of neutrophil extracellular traps (NETs) in response to infections were shown to be able to capture circulating cancer cells, and in doing so, support the development of metastatic disease. To be able to intervene on this process, understanding the exact molecular nature of these mechanisms is crucial. We therefore hypothesize and demonstrate that β1-integrin is an important factor mediating the interactions between circulating tumor cells and NETs. We show that β1-integrin expression on both cancer cells and NETs is important for the adhesion of circulating tumor cells to NETs both in vitro and in vivo. Using a murine model of intra-abdominal sepsis to mimic the postoperative inflammatory environment, we show that β1-integrin expression is upregulated in the context of inflammation in vivo. Ultimately, we show that this increased early cancer cell adhesion to NETs in vivo and this effect is abrogated when mice are administered DNAse 1. Our data therefore sheds light on the first molecular mechanism by which NETs can trap circulating tumor cells (CTCs), broadening our understanding of this process.

Comparing Laparoscopic to Endoscopic Resections for Early Gastric Cancer in a High Volume North American Center

Endoscopic submucosal dissection as an organ sparing option for early gastric cancer is becoming increasingly accepted as an alternative to laparoscopic gastrectomy. Given the very limited North American data, we sought to compare outcomes between endoscopic and laparoscopic resection of gastric malignant and premalignant tumors. Patients undergoing laparoscopic gastrectomy or endoscopic submucosal dissection from 2007 to 2014 for adenocarcinoma or dysplasia at the McGill University Health Center were identified from a prospectively collected database and dichotomized according to the surgical approach. Patient demographics, tumor characteristics, stage, oncologic outcome, length of stay, and postoperative complications were recorded. Of 155 patients with gastric cancer identified, 67 were treated by laparoscopic gastrectomy (n = 37) or endoscopic submucosal dissection (ESD) (n = 30). There were significantly more invasive lesions in the laparoscopic group and patients subject to ESD harbored more T1 lesions. No significant difference in the rate of R0 resection or overall complications was observed between the groups. Accordingly, length of stay was significantly shorter in the ESD group. There were no significant differences in terms of overall and disease-free survival. In selected patients, ESD is associated with improved short-term outcomes and provides an appropriate oncologic resection option in a North American patient cohort.

Management of esophageal perforation in the endoscopic era: Is operative repair still relevant?

BACKGROUND

With the introduction of new treatment paradigms for esophageal perforation, the management of this highly morbid condition is evolving. We reviewed our experience to investigate the modern management and outcomes of esophageal perforations with a focus on operatively repaired patients.

METHODS

A retrospective review of all esophageal perforations was conducted between August 2003 and January 2016.

RESULTS

A total of 48 patients were identified, with iatrogenic injury in 19 (40%), spontaneous perforation in 18 (38%), and traumatic/foreign body causes in 11 (23%). The distal esophagus was the site of perforation in 63% of the patients, and the duration of time between perforation and treatment was <24 hours in 60%. Nonoperative management was employed in 18 (38%) and operative repair in 30 (primary operative repair = 20, drainage = 4, esophagectomy = 6). Iatrogenic and traumatic perforations were more likely to be treated nonoperatively (68%), while all spontaneous perforations were treated by operative intervention. There were no complications or mortalities in the nonoperative group and only a 5% reintervention rate. In the operative group, complications occurred in 10 (33%), reinterventions in 13 (43%), and mortality in 2 (7%) patients.

CONCLUSION

Our study highlights the importance of considering the etiology of a perforation when planning management and the success of nonoperative treatment with careful patient selection. In addition, operative repair in septic patients yielded excellent outcomes and should be the standard for comparison in future studies exploring endoscopic approaches.

Application of an individualized operative strategy for wedge resection of gastric gastrointestinal stromal tumors: Effectiveness for tumors in difficult locations

BACKGROUND

There is some concern that wedge resection of gastric gastrointestinal stromal tumors is not feasible in certain anatomic locations, such as the cardia or antrum. We sought to review our experience with treatment of gastric gastrointestinal stromal tumors with a particular focus on nonanatomic wedge resections in these challenging locations.

METHODS

Patients undergoing resection of gastrointestinal stromal tumors from 2000-2014 at the Montreal General Hospital were identified from a prospectively collected database, and outcomes were tabulated. An individualized operative strategy was used to guide resection based on tumor location, size, and characteristics. Disease-free survival and overall survival analyzed using the Kaplan-Meier method. Data are presented as median (range).

RESULTS

We identified 59 patients who underwent operative resection for gastric gastrointestinal stromal tumors. Tumor location was fundus/body/greater curvature in 35 (59%) patients, lesser curvature in 8 (14%) patients, antrum in 8 (14%) patients, and cardia in 8 (14%) patients. Median tumor size was 4.5 cm (1.4-25 cm). The majority of cardia and antral lesions were removed with wedge resections (14/16, 87%). For cardial and antral tumors, on-table gastroscopy was used to guide the operative approach and prevent narrowing of the Gastroesophageal junction or pylorus in all patients undergoing wedge resection. Negative pathologic margins were achieved in all patients. The 5-year disease-free survival was 91% and 5-year overall survival was 95%.

CONCLUSION

When selected appropriately, and under the guidance of on-table gastroscopy, laparoscopic nonanatomic wedge resection can be performed successfully in the majority of cases, even for gastrointestinal stromal tumors near the GEJ or pylorus, with excellent oncologic outcomes.

Preoperative Chemoradiation Therapy Versus Chemotherapy in Patients Undergoing Modified En Bloc Esophagectomy for Locally Advanced Esophageal Adenocarcinoma: Is Radiotherapy Beneficial?

BACKGROUND

Preoperative chemotherapy (ChT) or chemoradiation (ChRT) are associated with improved outcomes compared with up-front surgical resection in patients with locally advanced esophageal adenocarcinoma (EAC). Two randomized controlled trials comparing these therapies included nonradical resection and failed to reach significance. We hypothesized that additional regional radiotherapy does not benefit patients undergoing en bloc resection.

METHODS

We performed a multiinstitutional study using three prospectively entered databases from high-volume esophageal centers. Inclusion criteria were patients with EAC treated with preoperative ChT or ChRT, followed by modified en bloc esophagectomy. To minimize issues of stage migration and heterogeneity, we limited the study to patients with cT3 N1 M0 EAC. Survival was assessed by the Kaplan-Meier method, and step-wise multivariable analyses were used to explore variables independently associated with survival outcomes. Radical resections included two- and three-field lymphadenectomies, dependent solely on surgeon/institutional preference.

RESULTS

We identified 214 patients with cT3 N1 disease, of which 114 underwent preoperative ChT vs 100 who underwent ChRT. Median survival was 31.2 months (95% confidence interval, 20.7 to 41.7 months) for the ChT group vs 39.2 months (95% confidence interval, 27.3 to 51.0 months) for the ChRT group (p = 0.665). Mortality at 90 days was 5.3% for ChT vs 4% for ChRT (p = 0.754). No differences were noted between patterns of locoregional and distant recurrence between both groups. There were no significant differences in major postoperative morbidity between both groups.

CONCLUSIONS

Given a modified en bloc esophagectomy, type of preoperative therapy was not a significant determinant of overall survival or disease-free survival. Although preoperative ChRT did not add perioperative risk, it also did not prolong survival. The role of preoperative radiotherapy in the setting of a planned radical resection should be further evaluated.

An enhanced recovery pathway reduces duration of stay and complications after open pulmonary lobectomy

BACKGROUND

Few studies have investigated the effectiveness of enhanced recovery pathways (ERP) for lung resection. This study estimates the impact of an ERP for lobectomy on duration of stay, complications, and readmissions.

METHODS

Patients undergoing open lobectomy were identified from an OR database between 2011 and 2013. Beginning September 2012, all patients were managed according to a 4-day multidisciplinary ERP with written daily patient education treatment plans, multimodal analgesia, early diet, structured mobilization and standardized drain management. Pre-pathway (PRE) and post-pathway (POST) patients were compared in terms of duration of stay, complications, and readmissions.

RESULTS

We identified 234 patients (PRE, 127; POST, 107). Groups were similar with respect to age, gender, American Society of Anesthesiologists score, and baseline pulmonary function. Compared with the PRE group, the POST group had decreased duration of stay (median, 6 [interquartile range (IQR), 5-7] vs 7 [6-10] days; P < .05), total complications (40 [37%] vs 64 [50%]; P < .05), urinary tract infections (3 [3%] vs 15 [12%]; P < .05), and chest tube duration (median, 4 [IQR, 3-6] vs 5 [4-7] days; P < .05), with no difference in readmissions (7 [7%] vs 6 [5%]; P < .05) or chest tube reinsertion (4 [4%] vs 6 [5%]; P < .05). Decreased duration of stay was driven by patients without complications (median, 5 [IQR, 4-6] vs 6 [5-7] days; P < .05).

CONCLUSION

Implementation of a multimodal ERP for lobectomy was associated with decreased duration of stay and complications with no difference in readmissions.

Simplified Human Neutrophil Extracellular Traps (NETs) Isolation and Handling

Neutrophil Extracellular Traps (NETs) have been recently identified as part of the neutrophil's antimicrobial armamentarium. Apart from their role in fighting infections, recent research has demonstrated that they may be involved in many other disease processes, including cancer progression. Isolating purified NETs is a crucial element to allow the study of these functions. In this video, we demonstrate a simplified method of cell free NET isolation from human whole blood using readily available reagents. Isolated NETs can then be used for immunofluorescence staining, blotting or various functional assays. This enables an assessment of their biologic properties in the absence of the potential confounding effects of neutrophils themselves. A density gradient separation technique is employed to isolate neutrophils from healthy donor whole blood. Isolated neutrophils are then stimulated by phorbol 12-myristate 13-acetate (PMA) to induce NETosis. Activated neutrophils are then discarded, and a cell-free NET stock is obtained. We then demonstrate how isolated NETs can be used in an adhesion assay with A549 human lung cancer cells. The NET stock is used to coat the wells of a 96 well cell culture plate O/N, and after ensuring an adequate NET monolayer formation on the bottom of the wells, CFSE labeled A549 cells are added. Adherent cells are quantified using a Nikon TE300 fluorescent microscope. In some wells, 1000U DNAse1 is added 10 min before counting to degrade NETs.

Abstract 1963: Toll-like receptor activation in bacterial pneumonia increases lung cancer cell adhesion and metastasis formation

Lung cancer is the leading cause of cancer death. Surgery remains essential for cure. However, postoperative infections particularly pneumonia remain high and confer an increased risk for metastasis. Emerging evidence implicates Toll-like receptor (TLR) signalling in tumor progression after systemic infection. We hypothesize bacterial pneumonia increases lung cancer cell adhesion and metastasis and that these effects are mediated in part by TLR signalling.

C57BL6 mice were intranasally inoculated with 10^5 CFU/mL of S. pneumonia and intrasplenically injected with H59 murine lung carcinoma 3 days later. Gross liver metastases were quantified at 2 weeks. Similarly, H59 cell adhesion to liver sinusoids was assessed by intravital microscopy (IVM) in wild type (WT) and TLR2 KO and TLR4 KO mice. WT, TLR2 KO, TLR4 KO, and MyD88 KO mice were intratracheally injected with lipoteichoic acid (LTA), lipopolysaccharide (LPS), or control (PBS). H59 cell adhesion was assessed 4 hours later with liver IVM. Using an in vitro pneumonia model, bronchoepithelial BEAS2B cells were stimulated with LPS, LTA, heat-inactivated E. coli or heat-inactivated S. pneumonia and supernatants collected. H59 cells were exposed to various supernatants and adhesion to extracellular matrix components was assessed. BEAS2B cells were also stimulated in the presence of anti-TLR2 antibodies or eritoran tetrasodium to inhibit TLR2 and TLR4 signalling respectively. Adhesion of supernatant treated cells to liver sinusoids was also assessed with IVM.

Mice inoculated with S. pneumonia demonstrated a 2-3 fold increase in gross liver metastases compared to non-infected controls. Similarly WT and TLR4 KO mice infected with S. pneumonia demonstrated a 4-5 fold increase in H59 adhesion to liver sinusoids versus control. TLR2 KO mice infected with S. pneumonia demonstrated no significant increase in H59 cell adhesion to liver. WT mice intratracheally injected with LTA or LPS demonstrated a 3-4 fold increase in cancer cell adhesion to liver compared to control. The increased adhesion for LTA was negated in TLR2 KO and MyD88 KO mice. For LPS conditions this increase was absent in TLR4 KO and MyD88 KO mice. Incubation with TLR-activated BEAS2B supernatants increased H59 cell adhesion to collagen 1, 4 and fibronectin 2-3 , 3-6 and 4-6 fold respectively versus media control and adhesion to liver sinusoids in vivo increased 3-4 fold. These effects were abrogated by blocking TLR2 for LTA or S. pneumonia conditions and by blocking TLR4 for LPS or E. coli conditions.

Bacterial pneumonia increases the metastatic potential of circulating lung cancer cells. These effects are facilitated in part by TLR2 or TLR4 activation and are mediated via interactions of the respiratory epithelium with the host systemically and lung cancer cells directly. TLR2 and TLR4 are potential therapeutic targets to decrease cancer recurrence in patients who suffer severe post-operative infections.

Citation Format: Stephen D. Gowing, Simon C. Chow, Jonathan J. Cools-Lartigue, Crystal B. Chen, Betty Giannias, France Bourdeau, Simon Rousseau, Salman T. Qureshi, Lorenzo E. Ferri. Toll-like receptor activation in bacterial pneumonia increases lung cancer cell adhesion and metastasis formation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1963. doi:10.1158/1538-7445.AM2014-1963

Functional outcomes and quality of life after proximal gastrectomy with esophagogastrostomy using a narrow gastric conduit

BACKGROUND

The best surgical approach for tumors of the proximal stomach remains controversial. For proximal gastrectomy (PG), the evidence regarding quality of life (QoL) and functional outcomes is controversial. Moreover, there are limited data from non-Asian settings.

METHODS

All patients who underwent PG from September 2005 to July 2013 were identified from an institutional database. Demographic, perioperative and pathologic characteristics were retrieved. Symptom scores (0 = best/4 = worst) for reflux symptoms, dysphagia and validated QoL metrics (FACT scale, where a higher score is better) were assessed during early and late follow-up. Eligible patients for analysis were those with no evidence of recurrence.

RESULTS

Of 465 upper gastrointestinal cancer resections, 50 were PG for adenocarcinoma (42; 84%), neuroendocrine carcinoma (5; 10%) or other pathologies (3; 6%). R0 resection was achieved in 44 (89.8%) of 49 patients with malignant tumors. Median lymph node collection was 32 (range 7-57). QoL scores did not differ from preoperative to early follow-up but increased compared to both at late follow-up [preoperative, 125 (interquartile range 105-140); early follow-up, 122.5 (97-142); late follow-up, 147 (132-159); p < 0.05]. At early and late follow-up, 9 (21.4%) of 42 and 10 (33.3%) of 30 patients reported reflux symptoms, but most were mild. Endoscopic signs of esophagitis were found in 7 (29%) of 24 patients, but only two of these reported reflux symptoms. Conversely only three of eight patients with reflux symptoms had esophagitis on endoscopy.

CONCLUSIONS

Global QoL is not reduced early after PG, and increases compared to baseline at late follow-up. Although reflux symptoms are reported by a quarter of patients, most are mild, and there is little correlation with esophagitis. PG should remain a viable option in the management of proximal gastric tumors.

Gram negative bacteria increase non-small cell lung cancer metastasis via Toll-like receptor 4 activation and mitogen-activated protein kinase phosphorylation

Surgery is required for the curative treatment of lung cancer but is associated with high rates of postoperative pneumonias predominantly caused by gram negative bacteria. Recent evidence suggests that these severe infectious complications may decrease long term survival after hospital discharge via cancer recurrence, but the mechanism is unclear. Lung cancer cells have recently been demonstrated to express Toll-like receptors (TLR) that mediate pathogen recognition. We hypothesized that incubation of non-small cell lung cancer (NSCLC) cells with heat-inactivated Escherichia coli can augment cancer cell adhesion, migration and metastasis via TLR4 signaling. Incubation of murine and human NSCLC cells with E. coli increased in vitro cell adhesion to collagen I, collagen IV and fibronectin, and enhanced in vitro migration. Using hepatic intravital microscopy, we demonstrated that NSCLC cells have increased in vivo adhesion to hepatic sinusoids after coincubation with gram negative bacteria. These enhanced cell adhesion and migration phenotypes following incubation with E. coli were attenuated at three levels: inhibition of TLR4 (Eritoran), p38 MAPK (BIRB0796) and ERK1/2 phosphorylation (PD184352). Incubation of murine NSCLC cells in vitro with E. coli prior to intrasplenic injection significantly augmented formation of in vivo hepatic metastases 2 weeks later. This increase was abrogated by NSCLC TLR4 blockade using Eritoran. TLR4 represents a potential therapeutic target to help prevent severe postoperative infection driven cancer metastasis.

Dynamic reprogramming of signaling upon met inhibition reveals a mechanism of drug resistance in gastric cancer

The Met receptor tyrosine kinase is activated or genetically amplified in some gastric cancers, but resistance to small-molecule inhibitors of Met often emerges in patients. We found that Met abundance correlated with a proliferation marker in patient gastric tumor sections, and gastric cancer cell lines that have MET amplifications depended on Met for proliferation and anchorage-independent growth in culture. Inhibition of Met induced temporal changes in gene expression in the cell lines, initiated by a rapid decrease in the expression of genes encoding transcription factors, followed by those encoding proteins involved in epithelial-mesenchymal transition, and finally those encoding cell cycle-related proteins. In the gastric cancer cell lines, microarray and chromatin immunoprecipitation analysis revealed considerable overlap between genes regulated in response to Met stimulation and those regulated by signal transducer and activator of transcription 3 (STAT3). The activity of STAT3, extracellular signal-regulated kinase (ERK), and the kinase Akt was decreased by Met inhibition, but only inhibitors of STAT3 were as effective as the Met inhibitor in decreasing tumor cell proliferation in culture and in xenografts, suggesting that STAT3 mediates the pro-proliferative program induced by Met. However, the phosphorylation of ERK increased after prolonged Met inhibition in culture, correlating with decreased abundance of the phosphatases DUSP4 and DUSP6, which inhibit ERK. Combined inhibition of Met and the mitogen-activated protein kinase kinase (MEK)-ERK pathway induced greater cell death in cultured gastric cancer cells than did either inhibitor alone. These findings indicate combination therapies that may counteract resistance to Met inhibitors.

Abstract B69: Dynamic reprogramming of signaling following Met inhibition reveals pathways for cell proliferation and negative feedback in gastric cancer

The Met receptor tyrosine kinase activates multiple signalling pathways in response to stimulation by ligand. However, the signalling events that occur under chronic Met activation in cancer cells are poorly understood. Utilizing a pharmacological small-molecule inhibitor of Met, we demonstrate that the gastric cancer cell lines, Okajima, MKN45, Snu-5 and KATO II are dependent on Met signalling for proliferation and anchorage-independent growth. We show that short-term inhibition of Met leads to waves of changes in gene expression such as a rapid loss of immediate-early genes, negative regulators, and a more delayed decrease in genes involved in the cell-cycle and proliferation. At the post-translational level, the Ras-Erk, PI3K-Akt and STAT3 pathways were all found to be dependent on Met signalling in these cells, though STAT3 signalling was the key requirement for proliferation, downstream from Met. We also observed the loss of negative regulators of Erk signalling, such as DUSP4 and DUSP6, which allowed for Mek-dependent reactivation of Erk, in the presence of Met inhibitor. As Met inhibitors are currently in clinical trials, it is essential to understand the molecular events that occur upon treatment, such that we can more effectively target sensitive tumours and avoid resistance.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B69.

Citation Format: Andrea Lai, Sean Cory, Hong Zhao, Bita Sehat, Ali Tofigh, Marie-Christine Guiot, Crista Thompson, Emily S. Bell, Nicholas Bertos, Lorenzo E. Ferri, Michael Hallett, Morag Park. Dynamic reprogramming of signaling following Met inhibition reveals pathways for cell proliferation and negative feedback in gastric cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B69.

Economic impact of an enhanced recovery pathway for oesophagectomy

BACKGROUND

Data are lacking to support the cost-effectiveness of enhanced recovery pathways (ERP) for oesophagectomy. The aim of this study was to investigate the impact of an ERP on medical costs for oesophagectomy.

METHODS

This study investigated all patients undergoing elective oesophagectomy between June 2009 and December 2011 at a single high-volume university hospital. From June 2010, all patients were enrolled in an ERP. Clinical outcomes were recorded for up to 30 days. Deviation-based cost modelling was used to compare costs between the traditional care and ERP groups.

RESULTS

A total of 106 patients were included (47 traditional care, 59 ERP). There were no differences in patient, pathological and operative characteristics between the groups. Median length of hospital stay (LOS) was lower in the ERP group (8 (interquartile range 7-18) days versus 10 (9-18) days with traditional care; P = 0·019). There was no difference in 30-day complication rates (59 per cent with ERP versus 62 per cent with traditional care; P = 0·803), and the 30-day or in-hospital mortality rate was low (3·8 per cent, 4 of 106). Costs in the on-course and minor-deviation groups were significantly lower after implementation of the ERP. The pathway-dependent cost saving per patient was €1055 and the overall cost saving per patient was €2013. One-way sensitivity analysis demonstrated that the ERP was cost-neutral or more costly only at extreme values of ward, operating and intensive care costs.

CONCLUSION

A multidisciplinary ERP for oesophagectomy was associated with cost savings, with no increase in morbidity or mortality.

Lipopolysaccharide-induced toll-like receptor 4 signaling enhances the migratory ability of human esophageal cancer cells in a selectin-dependent manner

BACKGROUND

Esophageal cancer is an aggressive malignancy, and emerging data suggest that postoperative infections may promote cancer progression. Systemic exposure to lipopolysaccharide (LPS), a Gram-negative bacterial antigen involved in such infections, has been shown to increase cancer cell adhesion to the hepatic sinusoids in vivo. We investigated the direct impact of LPS on the migratory ability of esophageal cancer cells via the LPS receptor toll-like receptor 4 (TLR4).

METHODS

Human esophageal squamous carcinoma cell lines and immortalized normal esophageal mucosa cells were tested for TLR4 surface expression by reverse transcription polymerase chain reaction (RT-PCR) and flow cytometry. TLR4 signaling in response to LPS stimulation was tested in these cells by measuring p38 MAP kinase phosphorylation on Western blot. The impact of TLR4 signaling was measured by static adhesion assays in vitro and on early in vivo migration by intravital microscopy of the liver.

RESULTS

Upon LPS stimulation, phosphorylation of p38 was detected in the human esophageal cancer cells HKESC-2. Also, LPS-stimulated HKESC-2 cells showed a twofold increased adhesion to fibronectin and to hepatic sinusoidal endothelium. These effects were abolished by TLR4 inhibition using the small-molecule inhibitor eritoran. Adhesion to fibronectin and hepatic sinusoidal endothelium was also diminished by blockade of p38 phosphorylation and inhibitors of selectin-selectin ligand binding.

CONCLUSION

LPS can increase the migratory ability of human esophageal cancer cells by increasing their adhesive properties through TLR4 signaling and selectin ligands. TLR4, p38, and selectin blockade may therefore prove to be a new therapeutic strategy for this aggressive malignancy.