Management of early oesophageal cancer: An overview

The incidence of esophageal cancer, namely the adenocarcinoma subtype, continues to increase exponentially on an annual basis. The indolent nature of the disease renders a significant proportion inoperable at first presentation, however, with the increased utilisation of endoscopy, many early lesions are now being identified which are suitable for endotherapeutic approaches. This article details the options available for dealing with early esophageal cancer by endoscopic mean obviating the need for surgery thereby avoiding the potential morbidity and mortality of such intervention.

Evaluating analgesia strategies in patients who have undergone oesophagectomy-a systematic review and network meta-analysis of randomised clinical trials

Optimal pain control following esophagectomy remains a topic of contention. The aim was to perform a systematic review and network meta-analysis (NMA) of randomized clinical trials (RCTs) evaluating the analgesia strategies post-esophagectomy. A NMA was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-NMA guidelines. Statistical analysis was performed using Shiny and R. Fourteen RCTs which included 565 patients and assessed nine analgesia techniques were included. Relative to systemic opioids, thoracic epidural analgesia (TEA) significantly reduced static pain scores at 24 hours post-operatively (mean difference (MD): -13.73, 95% Confidence Interval (CI): -27.01-0.45) (n = 424, 12 RCTs). Intrapleural analgesia (IPA) demonstrated the best efficacy for static (MD: -36.2, 95% CI: -61.44-10.96) (n = 569, 15 RCTs) and dynamic (MD: -42.90, 95% CI: -68.42-17.38) (n = 444, 11 RCTs) pain scores at 48 hours. TEA also significantly reduced static (MD: -13.05, 95% CI: -22.74-3.36) and dynamic (MD: -18.08, 95% CI: -31.70-4.40) pain scores at 48 hours post-operatively, as well as reducing opioid consumption at 24 hours (MD: -33.20, 95% CI: -60.57-5.83) and 48 hours (MD: -42.66, 95% CI: -59.45-25.88). Moreover, TEA significantly shortened intensive care unit (ICU) stays (MD: -5.00, 95% CI: -6.82-3.18) and time to extubation (MD: -4.40, 95% CI: -5.91-2.89) while increased post-operative forced vital capacity (MD: 9.89, 95% CI: 0.91-18.87) and forced expiratory volume (MD: 13.87, 95% CI: 0.87-26.87). TEA provides optimal pain control and improved post-operative respiratory function in patients post-esophagectomy, reducing ICU stays, one of the benchmarks of improved post-operative recovery. IPA demonstrates promising results for potential implementation in the future following esophagectomy.

Analysing the Combined Effects of Radiotherapy and Chemokine Receptor 5 Antagonism: Complementary Approaches to Promote T Cell Function and Migration in Oesophageal Adenocarcinoma

The presence of an immunosuppressive tumour microenvironment in oesophageal adenocarcinoma (OAC) is a major contributor to poor responses. Novel treatment strategies are required to supplement current regimens and improve patient survival. This study examined the immunomodulatory effects that radiation therapy and chemokine receptor antagonism impose on T cell phenotypes in OAC with a primary goal of identifying potential therapeutic targets to combine with radiation to improve anti-tumour responses. Compared with healthy controls, anti-tumour T cell function was impaired in OAC patients, demonstrated by lower IFN-γ production by CD4+ T helper cells and lower CD8+ T cell cytotoxic potential. Such diminished T cell effector functions were enhanced following treatment with clinically relevant doses of irradiation. Interestingly, CCR5+ T cells were significantly more abundant in OAC patient blood compared with healthy controls, and CCR5 surface expression by T cells was further enhanced by clinically relevant doses of irradiation. Moreover, irradiation enhanced T cell migration towards OAC patient-derived tumour-conditioned media (TCM). In vitro treatment with the CCR5 antagonist Maraviroc enhanced IFN-γ production by CD4+ T cells and increased the migration of irradiated CD8+ T cells towards irradiated TCM, suggesting its synergistic therapeutic potential in combination with irradiation. Overall, this study highlights the immunostimulatory properties of radiation in promoting anti-tumour T cell responses in OAC and increasing T cell migration towards chemotactic cues in the tumour. Importantly, the CCR5 antagonist Maraviroc holds promise to be repurposed in combination with radiotherapy to promote anti-tumour T cell responses in OAC.

Management of esophageal anastomotic leaks, a systematic review and network meta-analysis

There is currently no consensus as to how to manage esophageal anastomotic leaks. Intervention with endoscopic vacuum-assisted closure (EVAC), stenting, reoperation, and conservative management have all been mooted as potential options. To conduct a systematic review and network meta-analysis (NMA) to evaluate the optimal management strategy for esophageal anastomotic leaks. A systematic review was performed as per the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines with extension for NMA. NMA was performed using R packages and Shiny. In total, 12 retrospective studies were included, which included 511 patients. Of the 449 patients for whom data regarding sex was available, 371 (82.6%) were male, 78 (17.4%) were female. The average age of patients was 62.6 years (standard deviation 10.2). The stenting cohort included 245 (47.9%) patients. The EVAC cohort included 123 (24.1%) patients. The conservative cohort included 87 (17.0%) patients. The reoperation cohort included 56 (10.9%) patients. EVAC had a significantly decreased complication rate compared to stenting (odds ratio 0.23 95%, confidence interval [CI] 0.09;0.58). EVAC had a significantly lower mortality rate than stenting (odds ratio 0.43, 95% CI 0.21; 0.87). Reoperation was used in significantly larger leaks than stenting (mean difference 14.66, 95% CI 4.61;24.70). The growing use of EVAC as a first-line intervention in esophageal anastomotic leaks should continue given its proven effectiveness and significant reduction in both complication and mortality rates. Surgical management is often necessary for significantly larger leaks and will likely remain an effective option in uncontained leaks with systemic features.

Evaluating the Impact of Enhanced Recovery After Surgery Protocols on Surgical Outcomes Following Bariatric Surgery-A Systematic Review and Meta-analysis of Randomised Clinical Trials

BACKGROUND

Enhanced recovery after surgery (ERAS) programmes are evidence-based care improvement processes for surgical patients, which are designed to decrease the impact the anticipated negative physiological cascades following surgery.

AIM

To perform a systematic review and meta-analysis of randomised clinical trials (RCTs) to evaluate the impact of ERAS protocols on outcomes following bariatric surgery compared to standard care (SC).

METHODS

A systematic review was performed in accordance with PRISMA guidelines. Meta-analysis was performed using Review Manager version 5.4 RESULTS: Six RCTs including 740 patients were included. The mean age was 40.2 years, and mean body mass index was 44.1 kg/m2. Overall, 54.1% underwent Roux-en-Y gastric bypass surgery (400/740) and 45.9% sleeve gastrectomy (340/700). Overall, patients randomised to ERAS programmes had a significant reduction in nausea and vomiting (odds ratio (OR): 0.42, 95% confidence interval (CI): 0.19-0.95, P = 0.040), intraoperative time (mean difference (MD): 5.40, 95% CI: 3.05-7.77, P < 0.001), time to mobilisation (MD: - 7.78, 95% CI: - 5.46 to - 2.10, P < 0.001), intensive care unit stay (ICUS) (MD: 0.70, 95% CI: 0.13-1.27, P = 0.020), total hospital stay (THS) (MD: - 0.42, 95% CI: - 0.69 to - 0.16, P = 0.002), and functional hospital stay (FHS) (MD: - 0.60, 95% CI: - 0.98 to - 0.22, P = 0.002) compared to those who received SC.

CONCLUSION

ERAS programmes reduce postoperative nausea and vomiting, intraoperative time, time to mobilisation, ICUS, THS, and FHS compared to those who received SC. Accordingly, ERAS should be implemented, where feasible, for patients indicated to undergo bariatric surgery. Trial registration International Prospective Register of Systematic Reviews (PROSPERO - CRD42023434492.

Real-time ex vivo monitoring of NK cell migration toward obesity-associated oesophageal adenocarcinoma following modulation of CX3CR1

Oesophagogastric adenocarcinomas (OAC) are poor prognosis, obesity-associated cancers which may benefit from natural killer (NK) cell-based immunotherapies. Cellular immunotherapies encounter two key challenges to their success in OAC, namely recruitment to extratumoural tissues such as the omentum at the expense of the tumour and an immunosuppressive tumour microenvironment (TME) which can hamper NK cell function. Herein, we examined approaches to overcome the detrimental impact of obesity on NK cells and NK cell-based immunotherapies. We have demonstrated that NK cells migrate preferentially to the chemotactic signals of OAC patient-derived omentum over tumour in an ex vivo model of immune cell migration. We have identified CX3CR1 modulation and/or tumour chemokine profile remodelling as approaches to skew NK cell migration towards tumour. We also report targetable immunosuppressive facets of the obese OAC TME which dampen NK cell function, in particular cytotoxic capabilities. These data provide insights into approaches to therapeutically overcome key challenges presented by obesity and will inform superior design of NK cell-based immunotherapies for OAC.

Evaluating mesh fixation techniques for ventral hernia repair: A systematic review and network meta-analysis of randomised control trials

INTRODUCTION

There is uncertainty regarding the optimal mesh fixation techniques for laparoscopic ventral and incisional hernia repair.

AIM

To perform a systematic review and network meta-analysis of randomised control trials (RCTs) to investigate the advantages and disadvantages associated with absorbable tacks, non-absorbable tacks, non-absorbable sutures, non-absorbable staples, absorbable synthetic glue, absorbable sutures and non-absorbable tacks, and non-absorbable sutures and non-absorbable tacks.

METHODS

A systematic review was performed as per PRISMA-NMA guidelines. Odds ratios (ORs) and mean differences (MDs) were extracted to compare the efficacy of the surgical approaches.

RESULTS

Nine RCTs were included with 707 patients. Short-term pain was significantly reduced in non-absorbable staples (MD; -1.56, confidence interval (CI); -2.93 to -0.19) and non-absorbable sutures (MD; -1.00, CI; -1.60 to -0.40) relative to absorbable tacks. Recurrence, length of stay, operative time, conversion to open surgery, seroma and haematoma formation were unaffected by mesh fixation technique.

CONCLUSION

Short-term post-operative pain maybe reduced by the use of non-absorbable sutures and non-absorbable staples. There is clinical equipoise between each modality in relation to recurrence, length of stay, and operative time.

External validation of a nomogram predicting conditional survival after tri-modality treatment of esophageal cancer

BACKGROUND

A conditional survival nomogram was developed at a single high-volume center to predict 5-year overall survival for esophageal cancer patients after neoadjuvant chemoradiation and esophagectomy. The aim of this study was to externally validate the nomogram in a cohort of patients with esophageal adeno- or squamous cell carcinoma from another high-volume center.

METHODS

Consecutive patients with an esophageal adeno- or squamous cell carcinoma who had undergone esophagectomy after being treated with preoperative chemoradiation between 2004 and 2016 were selected from a prospectively maintained institutional database. The level of discrimination for prediction of 5-year overall survival was quantified by Harrell's C statistic. Calibration of the conditional survival nomogram was visualized by plotting predicted 5-year survival and observed 5-year survival for comparison.

RESULTS

Of the 296 patients examined, the probability of 5-year overall survival directly after surgery was 45% and increased to 51%, 68%, 78%, and 89% for each additional year survived. The predicted 5-year overall survival differed from the observed survival, with a calibration slope of 0.54, 0.55, 0.59, 0.73, and 1.09 directly after surgery and 1, 2, 3, and 4 years of survival after surgery, respectively. The nomogram's discrimination level for 5-year survival was moderate, with a C statistic of 0.65 compared to the 0.70 reported in the original study.

CONCLUSION

The nomogram model has moderate predictive discrimination and accuracy, supporting its applicability to external cohorts to predict conditional survival. Further validation studies should empirically assess the model for predictive performance.

Impact of the Surgical Approach for Neoadjuvantly Treated Gastroesophageal Junction Type II Tumors: A Multinational, High-volume Center Retrospective Cohort Analysis

OBJECTIVE

The aim of this study was to explore oncologic outcomes of transhiatal gastrectomy (THG) or transthoracic esophagectomy (TTE) for neoadjuvantly treated gastroesophageal junction (GEJ) Siewert type II adenocarcinomas, a multinational, high-volume center cohort analysis was undertaken.

BACKGROUND

Neoadjuvant radiochemotherapy or perioperative chemotherapy (CTx) followed by surgery is the standard therapy for locally advanced GEJ. However, the optimal surgical approach for type II GEJ tumors remains unclear, as the decision is mainly based on individual experience and assessment of operative risk.

METHODS

A retrospective analysis of 5 prospectively maintained databases was conducted. Between 2012 and 2021, 800 patients fulfilled inclusion criteria for type II GEJ tumors and neoadjuvant radiochemotherapy or CTx. The primary endpoint was median overall survival (mOS). Propensity score matching was performed to minimize selection bias.

RESULTS

Patients undergoing THG (n=163, 20.4%) had higher American Society of Anesthesiologists (ASA) classification and cT stage ( P <0.001) than patients undergoing TTE (n=637, 79.6%). Neoadjuvant therapy was different as the THG group were mainly undergoing CTx (87.1%, P <0.001). The TTE group showed higher tumor regression ( P =0.009), lower ypT/ypM categories (both P <0.001), higher nodal yield ( P =0.009) and higher R0 resection rate ( P =0.001). The mOS after TTE was longer (78.0 vs 40.0 months, P =0.013). After propensity score matching a higher R0 resection rate ( P =0.004) and mOS benefit after TTE remained ( P =0.04). Subgroup analyses of patients without distant metastasis ( P =0.037) and patients only after neoadjuvant chemotherapy ( P =0.021) confirmed the survival benefit of TTE. TTE was an independent predictor of longer survival.

CONCLUSION

Awaiting results of the randomized CARDIA trial, TTE should in high-volume centers be considered the preferred approach due to favorable oncologic outcomes.

Management Experiences of Post-Gastrectomy Severe Alkaline Reflux Esophagitis

Alkaline reflux esophagitis is a recognized complication of procedures that compromise the lower esophageal sphincter (LES), including gastrectomy. Incidence of reflux is dependent on the reconstructive procedure, with Roux-en-Y (RY) esophagojejunostomy commonly accepted as the optimal method. The authors report their experience of 5 patients who underwent remedial intervention for severe alkaline reflux esophagitis following gastric cancer surgery, over a 6-year period (2014-2020). Primary diagnoses encompassed 4 gastric adenocarcinomas and 1 gastric neuroendocrine tumor. Four patients previously underwent total gastrectomy and 1 subtotal gastrectomy with RY reconstruction. Onset of postoperative reflux symptoms ranged from 2 weeks to 3 years. Failing medical management, all patients underwent jejunojejunal anastomosis and Roux limb length revision with surgical jejunostomy. At follow-up, 4 out of 5 patients had some degree of symptom resolution and one with unresolved symptoms. The authors report our experience of managing this complication following gastrectomy with jejunojejunal anastomosis and Roux limb length revision.

Minimally Invasive and Open Gastrectomy for Gastric Cancer: A Systematic Review and Network Meta-Analysis of Randomized Clinical Trials

BACKGROUND AND OBJECTIVES

Optimal surgical management for gastric cancer remains controversial. We aimed to perform a network meta-analysis (NMA) of randomized clinical trials (RCTs) comparing outcomes after open gastrectomy (OG), laparoscopic-assisted gastrectomy (LAG), and robotic gastrectomy (RG) for gastric cancer.

METHODS

A systematic search of electronic databases was undertaken. An NMA was performed as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-NMA guidelines. Statistical analysis was performed using R and Shiny.

RESULTS

Twenty-two RCTs including 6890 patients were included. Overall, 49.6% of patients underwent LAG (3420/6890), 46.6% underwent OG (3212/6890), and 3.7% underwent RG (258/6890). At NMA, there was a no significant difference in recurrence rates following LAG (odds ratio [OR] 1.09, 95% confidence interval [CI] 0.77-1.49) compared with OG. Similarly, overall survival (OS) outcomes were identical following OG and LAG (OS: OG, 87.0% [1652/1898] vs. LAG: OG, 87.0% [1650/1896]), with no differences in OS in meta-analysis (OR 1.02, 95% CI 0.77-1.52). Importantly, patients undergoing LAG experienced reduced intraoperative blood loss, surgical incisions, distance from proximal margins, postoperative hospital stays, and morbidity post-resection.

CONCLUSIONS

LAG was associated with non-inferior oncological and surgical outcomes compared with OG. Surgical outcomes following LAG and RG superseded OG, with similar outcomes observed for both LAG and RG. Given these findings, minimally invasive approaches should be considered for the resection of local gastric cancer, once surgeon and institutional expertise allows.

Potential of damage associated molecular patterns in synergising radiation and the immune response in oesophageal cancer

BACKGROUND

There is an intimate crosstalk between cancer formation, dissemination, treatment response and the host immune system, with inducing tumour cell death the ultimate therapeutic goal for most anti-cancer treatments. However, inducing a purposeful synergistic response between conventional therapies and the immune system remains evasive. The release of damage associated molecular patterns (DAMPs) is indicative of immunogenic cell death and propagation of established immune responses. However, there is a gap in the literature regarding the importance of DAMP expression in oesophageal adenocarcinoma (OAC) or by immune cells themselves.

AIM

To investigate the effects of conventional therapies on DAMP expression and to determine whether OAC is an immunogenic cancer.

METHODS

We investigated the levels of immunogenic cell death-associated DAMPs, calreticulin (CRT) and HMGB1 using an OAC isogenic model of radioresistance. DAMP expression was also assessed directly using ex vivo cancer patient T cells (n = 10) and within tumour biopsies (n = 9) both pre and post-treatment with clinically relevant chemo(radio)therapeutics.

RESULTS

Hypoxia in combination with nutrient deprivation significantly reduces DAMP expression by OAC cells in vitro. Significantly increased frequencies of T cell DAMP expression in OAC patients were observed following chemo(radio)therapy, which was significantly higher in tumour tissue compared with peripheral blood. Patients with high expression of HMGB1 had a significantly better tumour regression grade (TRG 1-2) compared to low expressors.

CONCLUSION

In conclusion, OAC expresses an immunogenic phenotype with two distinct subgroups of high and low DAMP expressors, which correlated with tumour regression grade and lymphatic invasion. It also identifies DAMPs namely CRT and HMGB1 as potential promising biomarkers in predicting good pathological responses to conventional chemo(radio)therapies currently used in the multimodal management of locally advanced disease.

Metformin is a metabolic modulator and radiosensitiser in rectal cancer

Resistance to neoadjuvant chemoradiation therapy, is a major challenge in the management of rectal cancer. Increasing evidence supports a role for altered energy metabolism in the resistance of tumours to anti-cancer therapy, suggesting that targeting tumour metabolism may have potential as a novel therapeutic strategy to boost treatment response. In this study, the impact of metformin on the radiosensitivity of colorectal cancer cells, and the potential mechanisms of action of metformin-mediated radiosensitisation were investigated. Metformin treatment was demonstrated to significantly radiosensitise both radiosensitive and radioresistant colorectal cancer cells in vitro. Transcriptomic and functional analysis demonstrated metformin-mediated alterations to energy metabolism, mitochondrial function, cell cycle distribution and progression, cell death and antioxidant levels in colorectal cancer cells. Using ex vivo models, metformin treatment significantly inhibited oxidative phosphorylation and glycolysis in treatment naïve rectal cancer biopsies, without affecting the real-time metabolic profile of non-cancer rectal tissue. Importantly, metformin treatment differentially altered the protein secretome of rectal cancer tissue when compared to non-cancer rectal tissue. Together these data highlight the potential utility of metformin as an anti-metabolic radiosensitiser in rectal cancer.

The Impact of Bariatric Surgery on the Incidence of Colorectal Cancer in Patients with Obesity-a Systematic Review and Meta-analysis of Registry Data

PURPOSE

Cancer and obesity represent two of the most significant global health concerns. The risk of malignancy, including colorectal cancer (CRC), increases with obesity. The aim of this study was to perform a systematic review and meta-analysis to determine the value of bariatric surgery in reducing CRC risk in patients with obesity using registry data.

MATERIALS AND METHODS

A systematic review and meta-analysis were performed as per PRISMA guidelines. The risk of CRC was expressed as a dichotomous variable and reported as odds ratios (OR) with 95% confidence intervals (CIs) using the Mantel-Haenszel method. A multi-treatment comparison was performed, examining the risk reduction associated with existing bariatric surgery techniques. Analysis was performed using RevMan, R packages, and Shiny.

RESULTS

Data from 11 registries including 6,214,682 patients with obesity were analyzed. Of these, 14.0% underwent bariatric surgery (872,499/6,214,682), and 86.0% did not undergo surgery (5,432,183/6,214,682). The mean age was 49.8 years, and mean follow-up was 5.1 years. In total, 0.6% of patients who underwent bariatric surgery developed CRC (4,843/872,499), as did 1.0% of unoperated patients with obesity (54,721/5,432,183). Patients with obesity who underwent bariatric surgery were less likely to develop CRC (OR: 0.53, 95% CI: 0.36-0.77, P < 0.001, I2 = 99%). Patients with obesity undergoing gastric bypass surgery (GB) (OR: 0.513, 95% CI: 0.336-0.818) and sleeve gastrectomy (SG) (OR: 0.484, 95% CI: 0.307-0.763) were less likely to develop CRC than unoperated patients.

CONCLUSION

At a population level, bariatric surgery is associated with reduced CRC risk in patients with obesity. GB and SG are associated with the most significant reduction in CRC risk.

PROSPERO REGISTRATION

CRD42022313280.

Evaluating the oncological safety of neoadjuvant chemotherapy in locally advanced colon carcinoma: a systematic review and meta-analysis of randomised clinical trials and propensity-matched studies

PURPOSE

Use of neoadjuvant chemotherapy (NAC) for locally advanced colon cancer (LACC) remains controversial. An integrated analysis of data from high-quality studies may inform the long-term safety of NAC for this cohort. Our aim was to perform a systematic review and meta-analysis of randomised clinical trials (RCTs) and propensity-matched studies to assess the oncological safety of NAC in patients with LACC.

METHODS

A systematic review was performed as per preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Survival was expressed as hazard ratios using time-to-effect generic inverse variance methodology, while surgical outcomes were expressed as odds ratios (ORs) using the Mantel-Haenszel method. Data analysis was performed using Review Manager version 5.4.

RESULTS

Eight studies (4 RCTs and 4 retrospective studies) including 31,047 patients with LACC were included. Mean age was 61.0 years (range: 19-93 years) and mean follow-up was 47.6 months (range: 2-133 months). Of those receiving NAC, 4.6% achieved a pathological complete response and 90.6% achieved R0 resection (versus 85.9%, P < 0.001). At 3 years, patients receiving NAC had improved disease-free survival (DFS) (OR: 1.28, 95% confidence interval (CI): 1.02-1.60, P = 0.030) and overall survival (OS) (OR: 1.76, 95% CI: 1.10-2.81, P = 0.020). When using time-to-effect modelling, a non-significant difference was observed for DFS (HR: 0.79, 95% CI: 0.57-1.09, P = 0.150) while a significant difference in favour of NAC was observed for OS (HR: 0.75, 95% CI: 0.58-0.98, P = 0.030).

CONCLUSION

This study highlights the oncological safety of NAC for patients being treated with curative intent for LACC using RCT and propensity-matched studies only. These results refute current management guidelines which do not advocate for NAC to improve surgical and oncological outcomes in patients with LACC.

TRIAL REGISTRATION

International Prospective Register of Systematic Review (PROSPERO) registration: CRD4202341723.

PD-1 blockade attenuates surgery-mediated immunosuppression and boosts Th1 immunity perioperatively in oesophagogastric junctional adenocarcinoma

Introduction

This timely study assesses the immunosuppressive effects of surgery on cytotoxic Th1-like immunity and investigates if immune checkpoint blockade (ICB) can boost Th1-like immunity in the perioperative window in upper gastrointestinal cancer (UGI) patients.

Methods

PBMCs were isolated from 11 UGI patients undergoing tumour resection on post-operative days (POD) 0, 1, 7 and 42 and expanded ex vivo using anti-CD3/28 and IL-2 for 5 days in the absence/presence of nivolumab or ipilimumab. T cells were subsequently immunophenotyped via flow cytometry to determine the frequency of T helper (Th)1-like, Th1/17-like, Th17-like and regulatory T cell (Tregs) subsets and their immune checkpoint expression profile. Lymphocyte secretions were also assessed via multiplex ELISA (IFN-γ, granzyme B, IL-17 and IL-10). The 48h cytotoxic ability of vehicle-, nivolumab- and ipilimumab-expanded PBMCs isolated on POD 0, 1, 7 and 42 against radiosensitive and radioresistant oesophageal adenocarcinoma tumour cells (OE33 P and OE33 R) was also examined using a cell counting kit-8 (CCK-8) assay to determine if surgery affected the killing ability of lymphocytes and whether the use of ICB could enhance cytotoxicity.

Results

Th1-like immunity was suppressed in expanded PBMCs in the immediate post-operative setting. The frequency of expanded circulating Th1-like cells was significantly decreased post-operatively accompanied by a decrease in IFN-γ production and a concomitant increase in the frequency of expanded regulatory T cells with an increase in circulating levels of IL-10. Interestingly, PD-L1 and CTLA-4 immune checkpoint proteins were also upregulated on expanded Th1-like cells post-operatively. Additionally, the cytotoxic ability of expanded lymphocytes against oesophageal adenocarcinoma tumour cells was abrogated post-surgery. Of note, the addition of nivolumab or ipilimumab attenuated the surgery-mediated suppression of lymphocyte cytotoxicity, demonstrated by a significant increase in tumour cell killing and an increase in the frequency of Th1-like cells and Th1 cytokine production.

Conclusion

These findings support the hypothesis of a surgery-mediated suppression in Th1-like cytotoxic immunity and highlights a rationale for the use of ICB within the perioperative setting to abrogate tumour-promoting effects of surgery and ameliorate the risk of recurrence.

Comparing surgical outcomes of approaches to adrenalectomy - a systematic review and network meta-analysis of randomised clinical trials

BACKGROUND

No randomised clinical trials (RCTs) have simultaneously compared the safety of open (OA), transperitoneal laparoscopic (TLA), posterior retroperitoneal (PRA), and robotic adrenalectomy (RA) for resecting adrenal tumours.

AIM

To evaluate outcomes for OA, TLA, PRA, and RA from RCTs.

METHODS

A NMA was performed according to PRISMA-NMA guidelines. Analysis was performed using R packages and Shiny.

RESULTS

Eight RCTs with 488 patients were included (mean age: 48.9 years). Overall, 44.5% of patients underwent TLA (217/488), 37.3% underwent PRA (182/488), 16.4% underwent RA (80/488), and just 1.8% patients underwent OA (9/488). The mean tumour size was 35 mm in largest diameter with mean sizes of 44.3 mm for RA, 40.9 mm for OA, 35.5 mm for TLA, and 34.4 mm for PRA (P < 0.001). TLA had the lowest blood loss (mean: 50.6 ml), complication rates (12.4%, 14/113), and conversion to open rates (1.3%, 2/157), while PRA had the shortest intra-operative duration (mean: 94 min), length of hospital stay (mean: 3.7 days), lowest visual analogue scale pain scores post-operatively (mean: 3.7), and was most cost-effective (mean: 1728 euros per case). At NMA, there was a significant increase in blood loss for OA (mean difference (MD): 117.00 ml (95% confidence interval (CI): 1.41-230.00)) with similar blood loss observed for PRA (MD: - 10.50 (95% CI: - 83.40-65.90)) compared to TLA.

CONCLUSION

LTA and PRA are important contemporary options in achieving favourable outcomes following adrenalectomy. The next generation of RCTs may be more insightful for comparison surgical outcomes following RA, as this approach is likely to play a future role in minimally invasive adrenalectomy.

PROSPERO REGISTRATION

CRD42022301005.

The impact of histone deacetylase inhibitors on immune cells and implications for cancer therapy

Many cancers possess the ability to suppress the immune response to malignant cells, thus facilitating tumour growth and invasion, and this has fuelled research to reverse these mechanisms and re-activate the immune system with consequent important therapeutic benefit. One such approach is to use histone deacetylase inhibitors (HDACi), a novel class of targeted therapies, which manipulate the immune response to cancer through epigenetic modification. Four HDACi have recently been approved for clinical use in malignancies including multiple myeloma and T-cell lymphoma. Most research in this context has focussed on HDACi and tumour cells, however, little is known about their impact on the cells of the immune system. Additionally, HDACi have been shown to impact the mechanisms by which other anti-cancer therapies exert their effects by, for example, increasing accessibility to exposed DNA through chromatin relaxation, impairing DNA damage repair pathways and increasing immune checkpoint receptor expression. This review details the effects of HDACi on immune cells, highlights the variability in these effects depending on experimental design, and provides an overview of clinical trials investigating the combination of HDACi with chemotherapy, radiotherapy, immunotherapy and multimodal regimens.

Energy Metabolism, Metabolite, and Inflammatory Profiles in Human Ex Vivo Adipose Tissue Are Influenced by Obesity Status, Metabolic Dysfunction, and Treatment Regimes in Patients with Oesophageal Adenocarcinoma

Oesophageal adenocarcinoma (OAC) is a poor prognosis cancer with limited response rates to current treatment modalities and has a strong link to obesity. To better elucidate the role of visceral adiposity in this disease state, a full metabolic profile combined with analysis of secreted pro-inflammatory cytokines, metabolites, and lipid profiles were assessed in human ex vivo adipose tissue explants from obese and non-obese OAC patients. These data were then related to extensive clinical data including obesity status, metabolic dysfunction, previous treatment exposure, and tumour regression grades. Real-time energy metabolism profiles were assessed using the seahorse technology. Adipose explant conditioned media was screened using multiplex ELISA to assess secreted levels of 54 pro-inflammatory mediators. Targeted secreted metabolite and lipid profiles were analysed using Ultra-High-Performance Liquid Chromatography coupled with Mass Spectrometry. Adipose tissue explants and matched clinical data were collected from OAC patients (n = 32). Compared to visceral fat from non-obese patients (n = 16), visceral fat explants from obese OAC patients (n = 16) had significantly elevated oxidative phosphorylation metabolism profiles and an increase in Eotaxin-3, IL-17A, IL-17D, IL-3, MCP-1, and MDC and altered secretions of glutamine associated metabolites. Adipose explants from patients with metabolic dysfunction correlated with increased oxidative phosphorylation metabolism, and increases in IL-5, IL-7, SAA, VEGF-C, triacylglycerides, and metabolites compared with metabolically healthy patients. Adipose explants generated from patients who had previously received neo-adjuvant chemotherapy (n = 14) showed elevated secretions of pro-inflammatory mediators, IL-12p40, IL-1α, IL-22, and TNF-β and a decreased expression of triacylglycerides. Furthermore, decreased secreted levels of triacylglycerides were also observed in the adipose secretome of patients who received the chemotherapy-only regimen FLOT compared with patients who received no neo-adjuvant treatment or chemo-radiotherapy regimen CROSS. For those patients who showed the poorest response to currently available treatments, their adipose tissue was associated with higher glycolytic metabolism compared to patients who had good treatment responses. This study demonstrates that the adipose secretome in OAC patients is enriched with mediators that could prime the tumour microenvironment to aid tumour progression and attenuate responses to conventional cancer treatments, an effect which appears to be augmented by obesity and metabolic dysfunction and exposure to different treatment regimes.

Single-center experience in implementation of endoscopic surveillance protocol after esophagectomy

Esophageal cancer has a notably high recurrence rate with a paucity of robust evidence in defining the optimal surveillance strategy. The surveillance protocol at our institution comprises of annual esophagogastroduodenoscopy (OGD) from years 1 to 5 postoperatively. This study aims to evaluate the implementation of the endoscopic surveillance at our center and ascertain the value of endoscopy in detecting local recurrence after esophagectomy. A retrospective cohort review of all patients (320 patients) who underwent esophagectomy between 2013 and 2018 was conducted. The local esophageal cancer database and corresponding OGD reports were accessed to obtain data on demographics, operation details, local recurrence, and endoscopy performed. 1086 OGDs were performed between 2014 and 2020, broadly categorized to surveillance and symptomatic OGDs; 555 and 531, respectively. Surveillance OGDs detected four asymptomatic local recurrences, of which only one was treated with curative intent. Symptomatic OGDs resulted in a higher yield for the detection of local recurrence compared with surveillance endoscopy; 5% versus 0.7%, with overall median time-to-recurrence of 11.5 months (95% confidence interval 9-17). Of local recurrences, 85.7% occurred within the first 2 years postoperatively. The proportion of endoscopic findings differed between intensive and ad hoc surveillance cohorts for strictures, esophagitis, Barrett's esophagus, and sloughing. Thirteen patients were diagnosed with histologically confirmed Barrett's with no subsequent local recurrences. Surveillance endoscopy had a low positive yield rate with subsequent minimal survival benefits. Therefore, it is prudent to consider an alternative protocol that focuses on the period with the highest risk of recurrence and symptom presentation.

Endoscopic vacuum therapy significantly improves clinical outcomes of anastomotic leakages after 2-stage, 3-stage, and transhiatal esophagectomies

BACKGROUND

Anastomotic leakages after esophagectomies continue to constitute significant morbidity and mortality. Intrathoracic anastomoses pose a high risk for mediastinitis, sepsis, and death, if a leak is not addressed timely and appropriately. However, there are no standardized treatment recommendations or algorithms as for how to treat these leakages.

METHODS

The study included all patients at the University Hospital Regensburg, who developed an anastomotic leakage after esophagectomy with gastric pull-up reconstruction from 2007 to 2022. Patients receiving conventional treatment options for an anastomotic leakage (stents, drainage tubes, clips, etc.) were compared to patients receiving endoscopic vacuum-assisted closure (eVAC) therapy as their mainstay of treatment. Treatment failure was defined as cervical esophagostomy formation or death.

RESULTS

In total, 37 patients developed an anastomotic leakage after esophagectomy with a gastric pull-up reconstruction. Twenty patients were included into the non-eVAC cohort, whereas 17 patients were treated with eVAC. Treatment failure was observed in 50% of patients (n = 10) in the non-eVAC cohort and in 6% of patients (n = 1) in the eVAC cohort (p < 0.05). The 90-day mortality in the non-eVAC cohort was 15% (n = 3) compared to 6% (n = 1) in the eVAC cohort. Cervical esophagostomy formation was required in 40% of cases (n = 8) in the non-eVAC cohort, whereas no patient in the eVAC cohort underwent cervical esophagostomy formation.

CONCLUSION

eVAC therapy for leaking esophagogastric anastomoses appears to be superior to other treatment strategies as it significantly reduces morbidity and mortality. Therefore, we suggest eVAC as an essential component in the treatment algorithm for anastomotic leakages following esophagectomies, especially in patients with intrathoracic anastomoses.

Visceral adipose tissue secretome from early and late-stage oesophageal cancer patients differentially affects effector and regulatory T cells

AIM

Visceral obesity is a key risk factor in the development of oesophagogastric junctional adenocarcinoma (OGJ), predominantly via generation of systemic low grade inflammation. Obesity-induced inflammation promotes resistance to current standards of care, enhancing tumour cell growth and survival. This study investigates the effect of the visceral adipose tissue secretome from OGJ patients with early versus advanced tumours on T-cell immunity and the role of immune checkpoint blockade in enhancing anti-tumour immunity.

METHODS AND RESULTS

Visceral adipose conditioned media (ACM) from both early and late-stage OGJ patients significantly altered T cell activation status, upregulating co-stimulatory marker CD27 on T cells. ACM from both early and late-stage OGJ patients significantly altered immune checkpoint expression profiles downregulating immune checkpoints (ICs) on the surface of dual Th1/17-like and Th17-like cells and upregulating ICs on the surface of Th1-like cells and Treg cells. ACM derived from early-stage OGJ patients but not late-stage OGJ patients increased IFN-γ production by T cells. The addition of immune checkpoint blockers (ICBs) did not increase IFN-γ production by T cells in the presence of late-stage ACM, collectively highlighting the dichotomous immunostimulatory effect of early-stage ACM and immune-inhibitory effect of late-stage ACM. Interestingly, ACM from early-stage OGJ patients was more pro-inflammatory than ACM from late-stage patients, reflected by decreased levels of IL-17A/F, TNF-α, IL-1RA and IL-5.

CONCLUSION

The ACM-induced upregulation of ICs on T cells highlights a therapeutic vulnerability that could be exploited by ICBs to harness anti-cancer immunity and improve clinical outcomes for OGJ patients. Schematic workflow - (A) visceral adipose tissue was taken from OAC patients at time of surgery and cultured for 72 h in media. (B) The harvested ACM was co-cultured with healthy donor PBMCs that were concurrently activated with anti-CD3/28 for 48 h and T cell immunophenotyping was carried out by flow cytometry. Key findings - (A) Early and late stage ACM enhanced a Th1-like phenotype and upregulated CTLA-4 on Th1-like cells. A Th17-like phenotype was also enhanced in addition with a Treg-like phenotype. CTLA-4 and PD-L1 were upregulated on the surface of Treg-like cells. (B) ICB-attenuated IL-17 production by T cells. However, ACM attenuated ICB-mediated reduction in IL-10 production by T cells. Higher levels of pro-inflammatory factors were found in early stage ACM compared with late stage ACM.

Incidence and Impact of Non-alcoholic Fatty Liver Disease (NAFLD) in Patients with Adenocarcinoma of the Esophagus Treated with Curative Intent

BACKGROUND AND AIMS

Esophageal adenocarcinoma (EAC) is associated with visceral obesity (VO). Non-alcoholic fatty liver disease (NAFLD) is common within this phenotype; however, its incidence and clinical significance in EAC have not been studied.

STUDY DESIGN

A total of 559 patients with hepatic stetatosis (HS) defined by unenhanced CT were enrolled. In a sub-study, in 140 consecutive patients a liver biopsy was taken intraoperatively to study HS and non-alcoholic steatohepatitis (NASH). Postoperative complications were defined as per the Esophageal Complications Consensus Group (ECCG). Liver biochemistry was measured peri-operatively, with an ALT > 5 defined as acute liver injury (ALI). Mann-Whitney U test or Fisher's exact test was utilized and the Kaplan-Meier method for survival.

RESULTS

42% (n = 234/559) of patients had CT-defined HS. HS was associated with VO in 56% of cases, metabolic syndrome (Met S) in 37% and type 2 diabetes in 25%, compared with 44, 21, and 15% in non-HS patients (p < 0.01). Pathologic HS was present in 32% (45/140) and graded as mild, moderate, and severe in 73, 24, and 3%, respectively, with NASH reported in 16% and indefinite/borderline NASH in 42% of HS cases. Postoperative ALI was similar (p = 0.88) in both HS (10%) and non-HS cohorts (11%). Operative complication severity was similar in both cohorts. 5-yr survival was 53% (HS) vs 50% (p = 0.890).

CONCLUSION

This study establishes for the first time the incidence and clinical impact of NAFLD in EAC patients undergoing surgery and highlights no major impact on oncologic outcomes, nor in the severity of complications.

What works best in hiatus hernia repair, sutures alone, absorbable mesh or non-absorbable mesh? A systematic review and network meta-analysis of randomized clinical trials

Laparoscopic hiatal hernia repair (HHR) and fundoplication is a common low risk procedure providing excellent control of gastro-oesophageal reflux disease and restoring of normal anatomy at the hiatus. HHR may fail, however, resulting in hiatus hernia (HH) recurrence, and the use of tension-free mesh-augmented hernioplasty has been proposed to reduce recurrence. Previous research on this topic has been heterogeneous, including study methods, mesh type used and technique performed. A systematic review and network meta-analysis were carried out. An electronic systematic research was carried out using 'PUBMED', 'EMBASE', 'Medline (OVID)' and 'Web of Science', of articles identifying HHR with suture cruroplasty, non-absorbable mesh (NAM) and absorbable mesh (AM) reinforcement. Eight RCTs with 766 patients were evaluated. NAM had significantly (P < 0.05) lower early recurrence rates (OR: 0.225, 95% CI 0.0342, 0.871) compared with suture repair alone; however, no differences in late recurrences were evident. For AM, no difference in early (0.508, 95% CI 0.0605, 4.81) or late (1.07. 95% CI 0.116, 11.4) recurrence rates were evident compared with the suture only group. Major complication rates were similar in all groups. NAM reinforcement significantly reduced early HH recurrence when compared with sutured cruroplasty alone; however, late recurrence rates were similar with all techniques. Given the limited data in comparing AM with NAM, this study was unable to conclude which composition was significant. We emphasize caution when interpreting small sample size RCTs, and recommend more research with larger randomized studies.

Safety, efficacy, and cost-effectiveness of minimally invasive esophagectomies versus open esophagectomies: an umbrella review

Traditionally, esophageal oncological resections have been performed via open approaches with well-documented levels of morbidity and mortality complicating the postoperative course. In contemporary terms, minimally invasive approaches have garnered sustained support in all areas of surgery, and there has been an exponential adaptation of this technology in upper GI surgery with the advent of laparoscopic and robotic techniques. The current literature, while growing, is inconsistent in reporting on the benefits of minimally invasive esophagectomies (MIEs) and this makes it difficult to ascertain best practice. The objective of this review was to critically appraise the current evidence addressing the safety, efficacy, and cost-effectiveness of MIEs versus open esophagectomies. A systematic review of the literature was performed by searching nine electronic databases to identify any systematic reviews published on this topic and recommended Joanna Briggs Institute approach to critical appraisal, study selection, data extraction and data synthesis was used to report the findings. A total of 13 systematic reviews of moderate to good quality encompassing 143 primary trials and 36,763 patients were included in the final synthesis. Eleven reviews examined safety parameters and found a generalized benefit of MIE. Efficacy was evaluated by eight systematic reviews and found each method to be equivalent. There were limited data to judiciously appraise cost-effectiveness as this was only evaluated in one review involving a single trial. There is improved safety and equivalent efficacy associated with MIE when compared with open esophagectomy. Cost-effectiveness of MIE cannot be sufficiently supported at this point in time. Further studies, especially those focused on cost-effectiveness are needed to strengthen the existing evidence to inform policy makers on feasibility of increased assimilation of this technology into clinical practice.

Nutrient deprivation and hypoxia alter T cell immune checkpoint expression: potential impact for immunotherapy

Aim

Use of immune checkpoint blockade to enhance T cell-mediated immunity within the hostile tumour microenvironment (TME) is an attractive approach in oesophageal adenocarcinoma (OAC). This study explored the effects of the hostile TME, including nutrient deprivation and hypoxia, on immune checkpoint (IC) expression and T cell phenotypes, and the potential use of nivolumab to enhance T cell function under such conditions.

Methods and Results

ICs were upregulated on stromal immune cells within the tumour including PD-L2, CTLA-4 and TIGIT. OAC patient-derived PBMCs co-cultured with OE33 OAC cells upregulated LAG-3 and downregulated the co-stimulatory marker CD27 on T cells, highlighting the direct immunosuppressive effects of tumour cells on T cells. Hypoxia and nutrient deprivation altered the secretome of OAC patient-derived PBMCs, which induced upregulation of PD-L1 and PD-L2 on OE33 OAC cells thus enhancing an immune-resistant phenotype. Importantly, culturing OAC patient-derived PBMCs under dual hypoxia and glucose deprivation, reflective of the conditions within the hostile TME, upregulated an array of ICs on the surface of T cells including PD-1, CTLA-4, A2aR, PD-L1 and PD-L2 and decreased expression of IFN-γ by T cells. Addition of nivolumab under these hostile conditions decreased the production of pro-tumorigenic cytokine IL-10.

Conclusion

Collectively, these findings highlight the immunosuppressive crosstalk between tumour cells and T cells within the OAC TME. The ability of nivolumab to suppress pro-tumorigenic T cell phenotypes within the hostile TME supports a rationale for the use of immune checkpoint blockade to promote anti-tumour immunity in OAC.

Graphical abstract

Study schematic: (A) IC expression profiles were assessed on CD45+ cells in peripheral whole blood and infiltrating tumour tissue from OAC patients in the treatment-naïve setting. (B) PBMCs were isolated from OAC patients and expanded ex vivo for 5 days using anti-CD3/28 + IL-2 T cell activation protocol and then co-cultured for 48 h with OE33 cells. T cell phenotypes were then assessed by flow cytometry. (C) PBMCs were isolated from OAC patients and expanded ex vivo for 5 days using anti-CD3/28 + IL-2 T cell activation protocol and then further cultured under conditions of nutrient deprivation or hypoxia for 48 h and T cell phenotypes were then assessed by flow cytometry. Key findings: (A) TIGIT, CTLA-4 and PD-L2 were upregulated on CD45+ immune cells and CTLA-4 expression on CD45+ cells correlated with a subsequent decreased response to neoadjuvant regimen. (B) Following a 48 h co-culture with OE33 cells, T cells upregulated LAG-3 and decreased CD27 co-stimulatory marker. (C) Nutrient deprivation and hypoxia upregulated a range of ICs on T cells and decreased IFN-γ production by T cells. Nivolumab decreased IL-10 production by T cells under nutrient deprivation-hypoxic conditions.

Interventions targeting postoperative pulmonary complications (PPCs) in patients undergoing esophageal cancer surgery: a systematic review of randomized clinical trials and narrative discussion

Postoperative pulmonary complications (PPCs) represent the most common complications after esophageal cancer surgery. The lack of a uniform reporting nomenclature and a severity classification has hampered consistency of research in this area, including the study of interventions targeting prevention and treatment of PPCs. This systematic review focused on RCTs of clinical interventions used to minimize the impact of PPCs. Searches were conducted up to 08/02/2021 on MEDLINE (OVID), CINAHL, Embase, Web of Science, and the COCHRANE library for RCTs and reported in accordance with PRISMA guidelines. A total of 339 citations, with a pooled dataset of 1,369 patients and 14 RCTs, were included. Heterogeneity of study design and outcomes prevented meta-analysis. PPCs are multi-faceted and not fully understood with respect to etiology. The review highlights the paucity of high-quality evidence for best practice in the management of PPCs. Further research in the area of intraoperative interventions and early postoperative ERAS standards is required. A consistent uniform for definition of pneumonia after esophagectomy and the development of a severity scale appears warranted to inform further RCTs and guidelines.

Visceral obesity with and without metabolic syndrome: incidence and clinical impact in esophageal adenocarcinoma treated with curative intent

Visceral obesity (VO) and metabolic syndrome (MetS) are risk factors for esophageal adenocarcinoma (EAC); however, their impact on operative and oncological outcomes is unclear. The aim of this study was to determine the incidence of VO and MetS among patients with EAC, and to assess their independent impact on operative and oncological outcomes. A total of 454 consecutive patients undergoing treatment with curative intent were studied. Total, subcutaneous, visceral fat area (VFA), and lean body mass (LBM) were measured by computed tomography pretreatment, with VO defined as VFA >163.8cm2 for men and 80.1cm2 for women. MetS was defined per the ATPIII definition. Multivariable logistic and Cox proportional hazards regression were utilized to determine independent predictors of oncologic and operative outcomes. A total of 227 patients (50.0%) had VO. A total of 134 (30%) overall had MetS, 44% in the VO cohort. VO was associated with Barrett's esophagus (P = 0.002) and lower cT (P = 0.006) and cN stage (P = 0.011), and improved disease-specific (P = 0.021) and overall survival (P = 0.012). No survival benefit existed for patients with VO who also had MetS. For operative complications, neither VO nor MetS increased the severity of complications, or mortality. However, VO was significantly (P = 0.035) associated with anastomotic leak and pneumonia (P = 0.037). MetS alone did not increase complication risk. VO increases specific major operative complications with no increase in mortality. VO improved survival, mainly relating to earlier stage disease; however, co-existent MetS abrogated this benefit. These seemingly paradoxical outcomes highlight manageable and potentially targetable perioperative challenges in the context of an overall favorable oncologic vista.

Identification of plasma proteins associated with oesophageal cancer chemotherapeutic treatment outcomes using SWATH-MS

Oesophageal adenocarcinoma (OAC) is an aggressive cancer with a five-year survival of <15%. Current chemotherapeutic strategies only benefit a minority (20-30%) of patients and there are no methods available to differentiate between responders and non-responders. We performed quantitative proteomics using Sequential Window Acquisition of all THeoretical fragment-ion spectra-Mass Spectrometry (SWATH-MS) on albumin/IgG-depleted and non-depleted plasma samples from 23 patients with locally advanced OAC prior to treatment. Individuals were grouped based on tumour regression (TRG) score (TRG1/2/3 vs TRG4/5) after chemotherapy, and differentially abundant proteins were compared. Protein depletion of highly abundant proteins led to the identification of around twice as many proteins. SWATH-MS revealed significant quantitative differences in the abundance of several proteins between the two groups. These included complement c1q subunit proteins, C1QA, C1QB and C1QC, which were of higher abundance in the low TRG group. Of those that were found to be of higher abundance in the high TRG group, glutathione S-transferase pi (GSTP1) exhibited the lowest p-value and highest classification accuracy and Cohen's kappa value. Concentrations of these proteins were further examined using ELISA-based assays. This study provides quantitative information relating to differences in the plasma proteome that underpin response to chemotherapeutic treatment in oesophageal cancers. SIGNIFICANCE: Oesophageal cancers, including oesophageal adenocarcinoma (OAC) and oesophageal gastric junction cancer (OGJ), are one of the leading causes of cancer mortality worldwide. Curative therapy consists of surgery, either alone or in combination with adjuvant or neoadjuvant chemotherapy or radiation, or combination chemoradiotherapy regimens. There are currently no clinico-pathological means of predicting which patients will benefit from chemotherapeutic treatments. There is therefore an urgent need to improve oesophageal cancer disease management and treatment strategies. This work compared proteomic differences in OAC patients who responded well to chemotherapy as compared to those who did not, using quantitative proteomics prior to treatment commencement. SWATH-MS analysis of plasma (with and without albumin/IgG-depletion) from OAC patients prior to chemotherapy was performed. This approach was adopted to determine whether depletion offered a significant improvement in peptide coverage. Resultant datasets demonstrated that depletion increased peptide coverage significantly. Additionally, there was good quantitative agreement between commonly observed peptides. Data analysis was performed by adopting both univariate as well as multivariate analysis strategies. Differentially abundant proteins were identified between treatment response groups based on tumour regression grade. Such proteins included complement C1q sub-components and GSTP1. This study provides a platform for further work, utilising larger sample sets across different treatment regimens for oesophageal cancer, that will aid the development of 'treatment response prediction assays' for stratification of OAC patients prior to chemotherapy.

Abstract 1990: Exploring the immune-metabolic mechanisms of adipose tissue in oesophageal adenocarcinoma

Background: Oesophageal Adenocarcinoma (OAC) is the most strongly associated cancer with obesity. Approximately 75% of OAC patients are obese which results in chronic systemic low-grade inflammation, which is believed to drive carcinogenesis as well as influencing radiation treatment response. Adipose tissue is a regulatory organ with many downstream effects which are still not understood. This study aims to elucidate what influence adipose tissue metabolism and secretome have in treatment resistance and whether obesity alters this response.

Methods: Following patient consent, ex-vivo Visceral Adipose Tissue (VAT) explants were exposed to increasing doses of radiation with/without Palmitate and Oleate. Agilent Seahorse Xfe24 was used to measure oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) in VAT explants and mitochondrial metabolic parameters in dendritic cells (DCs) following treatment with Adipose Conditioned Media (ACM). Levels of DC maturation following irradiated ACM exposure and Macrophage (Mɸ) polarisation following ACM or Tumour Conditioned Media (TCM) exposure were analyzed by flow cytometry. Irradiated ACM and TCM were analyzed via MSD 54plex ELISA to assess secreted factors on angiogenic, chemokine, cytokine, inflammatory, TH17 or vascular injury panels.

Results: VAT explant energy metabolism showed a significant increase for OCR and ECAR with obesity and increasing radiation exposure however OCR was significantly decreased following Palmitate treatment compared with untreated and Oleate treated adipose explants (p&lt;0.05). DCs treated with iACM showed decreased expression of CD11c, CD80, CD86, HLA-DR, CD40 and PD-L1 with increasing radiation in a dose-dependent manner and decreased HLA-DR and CD54 following ACM exposure from obese versus non-obese patients (p&lt;0.05). Mɸ showed increased expression of pro-inflammatory and anti-inflammatory markers following ACM exposure but following TCM exposure only anti-inflammatory markers were increased (p&lt;0.05). DCs showed altered Proton Leak, Basal and ATP linked respiration following exposure to ACM (p&lt;0.05). Altered secretion of proinflammatory mediators was observed from the obese adipose secretome compared with non-obese patients and with increasing radiation doses (p&lt;0.05).

Conclusion: We have demonstrated that obesity and increasing radiation doses can significantly alter the immune-metabolic influences of adipose tissue and further studies are profiling the lipidomic and metabolomic landscape of the adipose secretome. Alterations in the secretome of adipose tissue could potentiate the tumor microenvironment and deleteriously affect immune cell function therefore further interrogation is required to fully elucidate the influence adipose tissue may have in treatment response.

Citation Format: Fiona O'Connell, Eimear Mylod, Ailsing B. Heeran, Noel E. Donlon, Maria Davern, Christine Butler, Anshul Bhardwaj, Claire Donohoe, Narayanasamy Ravi, John V. Renyolds, Margaret R. Dunne, Helen M. Roche, Jacintha O'Sullivan. Exploring the immune-metabolic mechanisms of adipose tissue in oesophageal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1990.

Impact of radiotherapy on the immune landscape in oesophageal adenocarcinoma

BACKGROUND

In the contemporary era of cancer immunotherapy, an abundance of clinical and translational studies have reported radiotherapy (RT) and immunotherapies as a viable option for immunomodulation of many cancer subtypes, with many related clinical trials ongoing. In locally advanced disease, chemotherapy or chemoradiotherapy followed by surgical excision of the tumour remain the principal treatment strategy in oesophageal adenocarcinoma (OAC), however, the use of the host immune system to improve anti-tumour immunity is rapidly garnering increased support in the curative setting.

AIM

To immunophenotype OAC patients’ immune checkpoint (IC) expression with and without radiation and evaluate the effects of checkpoint blockade on cell viability.

METHODS

In the contemporary era of cancer immunotherapy, an abundance of studies have demonstrated that combination RT and IC inhibitors (ICIs) are effective in the immunomodulation of many cancer subtypes, with many related clinical trials ongoing. Although surgical excision and elimination of tumour cells by chemotherapy or chemoradiotherapy remains the gold standard approach in OAC, the propagation of anti-tumour immune responses is rapidly garnering increased support in the curative setting. The aim of this body of work was to immunophenotype OAC patients’ IC expression with and without radiation and to establish the impact of checkpoint blockade on cell viability. This study was a hybrid combination of in vitro and ex vivo models. Quantification of serum immune proteins was performed by enzyme-linked immunosorbent assay. Flow cytometry staining was performed to evaluate IC expression for in vitro OAC cell lines and ex vivo OAC biopsies. Cell viability in the presence of radiation with and without IC blockade was assessed by a cell counting kit-8 assay.

RESULTS

We identified that conventional dosing and hypofractionated approaches resulted in increased IC expression (PD-1, PD-L1, TIM3, TIGIT) in vitro and ex vivo in OAC. There were two distinct subcohorts with one demonstrating significant upregulation of ICs and the contrary in the other cohort. Increasing IC expression post RT was associated with a more aggressive tumour phenotype and adverse features of tumour biology. The use of anti-PD-1 and anti-PD-L1 immunotherapies in combination with radiation resulted in a significant and synergistic reduction in viability of both radiosensitive and radioresistant OAC cells in vitro. Interleukin-21 (IL-21) and IL-31 significantly increased, with a concomitant reduction in IL-23 as a consequence of 4 Gray radiation. Similarly, radiation induced an anti-angiogenic tumour milieu with reduced expression of vascular endothelial growth factor-A, basic fibroblast growth factor, Flt-1 and placental growth factor.

CONCLUSION

The findings of the current study demonstrate synergistic potential for the use of ICIs and ionising radiation to potentiate established anti-tumour responses in the neoadjuvant setting and is of particular interest in those with advanced disease, adverse features of tumour biology and poor treatment responses to conventional therapies.

The immune response to major gastrointestinal cancer surgery and potential implications for adjuvant immunotherapy

The perioperative period theoretically is a critical time of opportunity for the progression of pre-existing tumour micrometastasis. Therefore,the timing of introducing cancer therapies including chemotherapy, radiation therapy and immunotherapies in the postoperative period is important. A thorough exploration of the perioperative immune events at a cellular level in combination with an intricate review of available clinical rials was conducted to extrapolate the effects of oncological surgery on the perioperative immune milieu.This is timely in view of the recently published Checkmate-577 trial which demonstrated significant disease-free survival in carcinoma of the gastroesophageal junction with the use of adjuvant anti-programmed cell deathprotein 1(PD-1) immunotherapy.This review focusing in particular on perioperative immunosuppression, identifies potential modifiable factors, the effects of perioperative conditioning and optimisation, the most recent trials in the curative setting for Gastrointestinal malignancies and the new treatment avenues possible in the context of the combination of immunotherapy and major oncological gastrointestinal surgery.

PD-1 inhibitors in esophageal cancer: a systematic review of the oncological outcomes associated with PD-1 blockade and the evolving therapeutic paradigm

Patients with esophageal or gastroesophageal junction (GEJ) cancer who fail to respond to chemoradiotherapy have a poor clinical prognosis. Recent clinical trials have investigated the use of immune checkpoint inhibitors in these patients. The use of programmed cell death protein 1 (PD-1) inhibitors has emerged as exciting therapeutic options in the curative and palliative setting of other solid tumors. We assessed the efficacy and safety of PD-1 inhibitors in esophageal and GEJ cancers. This systematic review was performed in accordance with the PRISMA guidelines. A comprehensive electronic literature search from the EMBASE, Pubmed, Scopus, MEDLINE, and Google Scholar databases was conducted up to 25 July 2021. This review identified 11 eligible studies reporting outcomes of 3451 patients treated with PD-1 blockade compared with 2286 patients treated with either a placebo or the standard regimen of chemotherapy. Clinically significant improvements in median overall survival have been demonstrated in advanced and metastatic esophageal and GEJ cancer while maintaining acceptable safety profiles. Promising survival data have also recently emerged from PD-1 blockade in the adjuvant setting. PD-1 blockade in esophageal and GEJ cancer has delivered impressive survival benefit while remaining well tolerated. Its use in the adjuvant setting will further advance treatment options, and more advancements in this area of therapy are highly anticipated. However, further characterization of the PD-1/programmed death ligand-1 pathway and elucidation of biomarkers to predict response are required to optimize patient selection.

Endobronchial valve use in COVID-19 related pneumothorax and persistent air leak

Pneumothoraces may occur rarely in coronavirus (COVID-19) patients, often resulting from a combination of fibrotic parenchymal changes and prolonged high-pressure ventilation. Very few studies have been published describing the management of pneumothorax in the novel COVID-19 pneumonia patients. Although chest drain insertion represents the first line of treatment, a persistent pneumothorax and air leak requiring intervention could be managed by a thoracoscopic procedure or, as is the case here, by endobronchial valve insertion. Endobronchial valve insertion is a minimally invasive technique that provides a treatment option in patients with severe parenchymal COVID-19 related lung disease. As far as the authors are aware this is the first report of the use of endobronchial valves in a COVID-19 patient.

Investigating the susceptibility of treatment-resistant oesophageal tumours to natural killer cell-mediated responses

The majority of oesophageal adenocarcinoma (OAC) patients do not respond to multimodal treatment regimens and face dismal survival rates. Natural killer (NK) cells are crucial anti-tumour immune cells, and this study investigated the susceptibility of treatment-resistant OAC cells to these potent tumour killers. Natural killer receptor (NKR) ligand expression by OE33CisP (cisplatin-sensitive) and OE33CisR (cisplatin-resistant) cells was investigated. The immunomodulatory effects of OE33CisP and OE33CisR cells on NK cell phenotype and function were assessed. Finally, the impact of chemotherapy regimens on NKR ligand shedding was examined. Our data revealed significantly less surface expression of activating ligands B7-H6, MICA/B, ULBP-3 and activating/inhibitory ligands PVRL-1 and PVRL-4 by OE33CisR cells, compared to OE33CisP cells. Co-culture with OE33CisR cells reduced the frequencies of NKp30⁺ and NKp46⁺ NK cells and increased frequencies of TIGIT⁺, FasL⁺ and TRAIL⁺ NK cells. Frequencies of IFN-γ-producing NK cells increased while frequencies of TIM-3⁺ NK cells decreased after culture with OE33CisP and OE33CisR cells. Frequencies of circulating NKp30⁺ NK cells were significantly lower in OAC patients with the poorest treatment response and in patients who received FLOT chemotherapy, while B7-H6 shedding by OAC tumour cells was induced by FLOT. Overall, OE33CisR cells express less activating NKR ligands than OE33CisP cells and have differential effects on NKR expression by NK cells. However, neither cell line significantly dampened NK cell cytokine production, death receptor expression or degranulation. In addition, our data indicate that FLOT chemotherapy may promote B7-H6 shedding and immune evasion with detrimental consequences in OAC patients.

Cooperation between chemotherapy and immune checkpoint blockade to enhance anti-tumour T cell immunity in oesophageal adenocarcinoma

Response rates to immune checkpoint blockade (ICB) remain low in oesophageal adenocarcinoma (OAC). Combining ICB with immunostimulatory chemotherapies to boost response rates is an attractive approach for converting 'cold' tumours into 'hot' tumours. This study profiled immune checkpoint (IC) expression on circulating and tumour-infiltrating T cells in OAC patients and correlated these findings with clinical characteristics. The effect of first-line chemotherapy regimens (FLOT and CROSS) on anti-tumour T cell immunity was assessed to help guide design of ICB and chemotherapy combinations in the first-line setting. The ability of ICB to enhance lymphocyte-mediated cytolysis of OAC cells in the absence and presence of post-FLOT and post-CROSS chemotherapy tumour cell secretome was assessed by a CCK-8 assay. Expression of ICs on T cells positively correlated with higher grade tumours and a subsequent poor response to neoadjuvant treatment. First-line chemotherapy regimens substantially altered IC expression profiles of T cells increasing PD-1, A2aR, KLRG-1, PD-L1, PD-L2 and CD160 and decreasing TIM-3 and LAG-3. In addition, pro-inflammatory T cell cytokine profiles were enhanced by first-line chemotherapy regimens. T cell activation status was significantly altered; both chemotherapy regimens upregulated co-stimulatory markers ICOS and CD69 yet downregulated co-stimulatory marker CD27. However, ICB attenuated chemotherapy-induced downregulation of CD27 on T cells and promoted differentiation of effector memory T cells into a terminally differentiated state. Importantly, dual nivolumab-ipilimumab treatment increased lymphocyte-mediated cytolysis of OAC cells, an effect further enhanced in the presence of post-FLOT tumour cell secretome. These findings justify a rationale to administer ICBs concurrently with first-line chemotherapies.

The Impact of Esophageal Oncological Surgery on Perioperative Immune Function; Implications for Adjuvant Immune Checkpoint Inhibition

Background

Immune checkpoint inhibitors (ICIs) are being investigated for their role as an adjunct in the multimodal treatment of esophageal adenocarcinoma (EAC). The most effective time to incorporate ICIs remains unknown. Our study profiles systemic anti-tumor immunity perioperatively to help inform the optimal timing of ICIs into current standards of care for EAC patients.

Methods

Systemic immunity in 11 EAC patients was phenotyped immediately prior to esophagectomy (POD-0) and post-operatively (POD)-1, 3, 7 and week 6. Longitudinal serological profiling was conducted by ELISA. The frequency of circulating lymphocytes, activation status, immune checkpoint expression and damage-associated molecular patterns was assessed by flow cytometry.

Results

The frequency of naïve T-cells significantly increased in circulation post-esophagectomy from POD-0 to POD-7 (p<0.01) with a significant decrease in effector memory T-cells by POD7 followed by a subsequent increase by week 6 (p<0.05). A significant increase in activated circulating CD27⁺ T-cells was observed from POD-0 to POD-7 (p<0.05). The percentage of PD-1⁺ and CTLA-4⁺ T-cells peaked on POD-1 and was significantly decreased by week 6 (p<0.01). There was a significant increase in soluble PD-1, PD-L2, TIGIT and LAG-3 from POD-3 to week 6 (p<0.01). Increased checkpoint expression correlated with those who developed metastatic disease early in their postoperative course. Th1 cytokines and co-stimulatory factors decreased significantly in the immediate post-operative setting, with a reduction in IFN-γ, IL-12p40, IL-1RA, CD28, CD40L and TNF-α. A simultaneous increase was observed in Th2 cytokines in the immediate post-operative setting, with a significant increase in IL-4, IL-10, IL-16 and MCP-1 before returning to preoperative levels at week 6.

Conclusion

Our study highlights the prevailing Th2-like immunophenotype post-surgery. Therefore, shifting the balance in favour of a Th1-like phenotype would offer a potent therapeutic approach to promote cancer regression and prevent recurrence in the adjuvant setting and could potentially propagate anti-tumour immune responses perioperatively if administered in the immediate neoadjuvant setting. Consequently, this body of work paves the way for further studies and appropriate trial design is needed to further interrogate and validate the use of ICI in the multimodal treatment of locally advanced disease in the neoadjuvant and adjuvant setting.

PD-1 and TIGIT blockade differentially affect tumour cell survival under hypoxia and glucose deprived conditions in oesophageal adenocarcinoma; implications for overcoming resistance to PD-1 blockade in hypoxic tumours

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PD-1 and TIGIT expression are highly expressed on the surface of oesophageal epithelial cells during the early stages of metaplasia.

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Glucose deprivation and hypoxia upregulate PD-1 and TIGIT on the surface of oesophageal adenocarcinoma (OAC) cells in vitro.

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PD-1 and TIGIT blockade decrease Bcl-2 and Bcl-xL expression in OAC cells.

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PD-1 blockade in OAC cells enhances basal respiration and glycolytic reserve and upregulates GLUT1 on the surface of a subpopulation of OAC cells.

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PD-1 inhibition confers a survival advantage to OAC cells under glucose deprivation and hypoxia.

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TIGIT blockade decreases OAC cell proliferation and induces OAC cell death under normoxia, hypoxia and nutrient deprivation.

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TIGIT blockade increases ECAR yet decreases a range of metabolic parameters in OAC cells.

Recent studies have demontrated that immune checkpoint receptors are expressed on the surface of oesophageal adenocarcinoma (OAC) cells and might confer a survival advantage. This study explores the role of PD-1 and TIGIT signalling in OAC cells in either promoting or inhibiting the survival of OAC cells under characteristic features of the tumour microenvironment including nutrient-deprivation and hypoxia. PD-1 and TIGIT are expressed in normal and pre-malignant oesophageal epithelial cells and this expression significantly decreases along the normal- Barrett's Oesophagus- OAC disease sequence. However, glucose-deprivation and hypoxia significantly upregulated PD-1 and TIGIT on the surface of OAC cells in vitro. PD-1 blockade decreased OAC cell proliferation under normoxia but enhanced proliferation and decreased cell death in OAC cells under hypoxia and glucose-deprivation. TIGIT blockade decreased proliferation and induced OAC cell death, an effect that was maintained under nutrient-deprivation and hypoxia. Basal respiration and glycolytic reserve were enhanced and GLUT1 was upregulated on the surface of a subpopulation of OAC cells following PD-1 blockade. In contrast, TIGIT blockade enhanced a glycolytic phenotype in OAC cells, yet decreased other metabolic parameters including oxidative phosphorylation and basal respiration. Interestingly, inhibition of oxidative phosphorylation significantly upregulated TIGIT expression and inhibition of oxidative phosphorylation and glycolysis significantly decreased PD-1 on the surface of a subpopulation of OAC cells in vitro. These findings suggest an immune-independent mechanism for PD-1 inhibitor resistance in hypoxic tumours and suggest that TIGIT might be a more effective therapeutic target in OAC compared with PD-1 for treating hypoxic tumours.

Prostate radiotherapy and the risk of secondary rectal cancer-a meta-analysis

PURPOSE

Radiotherapy is being used increasingly in the treatment of prostate cancer. However, ionising radiation may confer a small risk of a radiation-induced secondary malignancy. We aim to assess the risk of rectal cancer following pelvic radiotherapy for prostate cancer.

METHODS

A search was conducted of the PubMed/MEDLINE, EMBASE and Web of Science databases identifying studies reporting on the risk of rectal cancer following prostatic radiotherapy. Studies must have included an appropriate control group of non-irradiated prostate cancer patients. A meta-analysis was performed to assess the risk of prostatic radiotherapy on subsequent rectal cancer diagnosis.

RESULTS

In total, 4757 articles were screened with eight studies meeting the predetermined criteria. A total of 796,386 patients were included in this meta-analysis which showed an increased odds ratio (OR) for subsequent rectal cancer in prostate cancer patients treated with radiotherapy compared to those treated by non-radiotherapy means (OR 1.45, 1.07-1.97, p = 0.02).

CONCLUSION

These findings confirm that prostate radiotherapy significantly increases the risk of subsequent rectal cancer. This risk has implications for treatment selection, surveillance and patient counselling. However, it is crucial that this information is presented in a rational and comprehensible manner that does not disproportionately frighten or deter patients from what might be their most suitable treatment modality.

Prospective study of surgical site infections post-open esophageal cancer surgery, and the impact of care bundles

SSIs represent common infection-related morbidity following major surgery. Modern care bundles have been established as prophylactic measures aimed at preventing SSI occurring postoperatively. SSI incidence and data on common culprit pathogens post-esophagectomy for cancer have not been previously reported. Patients (2013-2018) treated with curative intent were studied. SSI was defined as per the Center for Disease Control (CDC) definition. A care bundle pathway following the National Institute for Clinical Excellence (NICE) guidelines for prevention of SSIs was introduced in 2013 and was audited quarterly. Risk factors and associations of SSIs were analyzed, as was the prevalence of isolated pathogens. Multivariable logistic regression examined independently predictive factors of SSIs and oncologic outcomes. Of 343 patients, 34 (9.9%) developed a postoperative SSI, with a median (range) of 8 (6-17). Quarterly audit carried out over 6 years showed no significant annual variance or trend. The most prevalent pathogen cultured was Methicillin-sensitive Staphylococcus aureus (MSSA) in nine patients (32%) followed by Candida albicans (29%), Escherichia coli (14%), and Enterococcus faecium (11%). SSI was significantly associated with pneumonia (P = 0.001), respiratory failure (P = 0.014), atrial fibrillation (P = 0.004), anastomotic leak (P < 0.001), and in-hospital blood transfusions (P = 0.031). SSI did not impact the overall survival (P = 0.951). SSI rates can be maintained at less than 10% using strict care bundles and regular audit. The most common culprit pathogen is gram-positive MSSA representing 32% of cases. These data are novel and may represent a modern benchmark for SSI post-open esophagectomy for cancer. This study highlights the incidence and associations of SSI post-esophageal cancer surgery.

The Omentum in Obesity-Associated Cancer: A Hindrance to Effective Natural Killer Cell Migration towards Tumour Which Can Be Overcome by CX3CR1 Antagonism

Simple Summary

Oesophagogastric adenocarcinomas (OAC) are cancers of the food pipe and stomach which have a strong link with obesity. Natural killer (NK) cells are assassins of the immune system and are crucial for eliminating cancer. We have shown previously that NK cells are pulled into fat in OAC patients by a signalling protein called fractalkine (CX3CL1). Once in fat, NK cells die or are profoundly altered. This diminishes their ability to kill the tumour. We report that exposure to fat can reduce movement of NK cells towards the tumour. However, if a drug called a CX3CR1 antagonist is used to antagonise the receptor for fractalkine, we can restore NK cell movement towards the tumour. When we activate NK cells with a protein called IL-15, fractalkine can reduce its effect on NK cells. This provides further evidence for using CX3CR1 antagonists to reduce NK cell migration to fat and boost NK cell movement to the tumour.

Abstract

Oesophagogastric adenocarcinomas (OAC) are obesity-associated malignancies, underpinned by severe immune dysregulation. We have previously shown that natural killer (NK) cells preferentially migrate to OAC omentum, where they undergo phenotypic and functional alterations and apoptosis. Furthermore, we have identified the CX3CR1:fractalkine (CX3CL1) pathway as pivotal in their recruitment to omentum. Here, we elucidate whether exposure to the soluble microenvironment of OAC omentum, and in particular fractalkine and IL-15 affects NK cell homing capacity towards oesophageal tumour. Our data uncover diminished NK cell migration towards OAC tumour tissue conditioned media (TCM) following exposure to omental adipose tissue conditioned media (ACM) and reveal that this migration can be rescued with CX3CR1 antagonist E6130. Furthermore, we show that fractalkine has opposing effects on NK cell migration towards TCM, when used alone or in combination with IL-15 and uncover its inhibitory effects on IL-15-mediated stimulation of death receptor ligand expression. Interestingly, treatment with fractalkine and/or IL-15 do not significantly affect NK cell adhesion to MAdCAM-1, despite changes they elicit to the expression of integrin α4β7. This study provides further evidence that CX3CR1 antagonism has therapeutic utility in rescuing NK cells from the deleterious effects of the omentum and fractalkine in OAC, thus limiting their dysfunction.

Management of chyle leaks following esophageal resection: a systematic review

BACKGROUND

Chyle leakage is an uncommon but potentially life-threatening complication following esophageal resections. The optimal management strategy is not clear, with a limited evidence base.

METHODS

Searches were conducted up to 31 December 2020 on MEDLINE, Embase, and Web of Science for randomized trials or retrospective studies that evaluated the management of chyle leakage following esophageal resection. Two authors independently screened studies, extracted data, and assessed for bias. The protocol was prospectively registered on PROSPERO (CRD: 42021224895) and reported in accordance with preferred reporting items for systematic reviews and meta-analyses guidelines.

RESULTS

A total of 530 citations were reviewed. Twenty-five studies, totaling 1016 patients met the inclusion criteria, including two low-quality clinical trials and 23 retrospective case series. Heterogeneity of study design and outcomes prevented meta-analysis. The overall incidence of chyle leak/fistula was 3.2%. Eighteen studies describe management of chyle leaks conservatively, 17 by surgical ligation of the thoracic duct, 5 by pleurodesis, and 6 described percutaneous lymphangiography with thoracic duct embolization or disruption.

CONCLUSIONS

The evidence base for optimal management of chyle leakage postesophagectomy is lacking, which may be related to its low incidence. There is a paucity of high-quality prospective studies directly comparing treatment modalities, but there is some low-certainty evidence that percutaneous approaches have reduced morbidity but lower efficacy compared with surgery. Further high-quality, prospective studies that compare interventions at different levels of severity are needed to determine the optimal approach to treatment.

Opposing Immune-Metabolic Signature in Visceral Versus Subcutaneous Adipose Tissue in Patients with Adenocarcinoma of the Oesophagus and the Oesophagogastric Junction

Oesophageal adenocarcinoma (OAC) is an exemplar model of obesity-associated cancer. Previous work in our group has demonstrated that overweight/obese OAC patients have better responses to neoadjuvant therapy, but the underlying mechanisms are unknown. Unravelling the immune-metabolic signatures of adipose tissue may provide insight for this observation. We hypothesised that different metabolic pathways predominate in visceral (VAT) and subcutaneous adipose tissue (SAT) and inflammatory secretions will differ between the fat depots. Real-time ex vivo metabolic profiles of VAT and SAT from 12 OAC patients were analysed. These samples were screened for the secretion of 54 inflammatory mediators, and data were correlated with patient body composition. Oxidative phosphorylation (OXPHOS) was significantly higher in VAT when compared to SAT. OXPHOS was significantly higher in the SAT of patients receiving neoadjuvant treatment. VEGF-A, VEGF-C, P1GF, Flt-1, bFGF, IL-15, IL-16, IL-17A, CRP, SAA, ICAM-1, VCAM-1, IL-2, IL-13, IFN-γ, and MIP-1β secretions were significantly higher from VAT than SAT. Higher levels of bFGF, Eotaxin-3, and TNF-α were secreted from the VAT of obese patients, while higher levels of IL-23 and TARC were secreted from the SAT of obese patients. The angiogenic factors, bFGF and VEGF-C, correlated with visceral fat area. Levels of OXPHOS are higher in VAT than SAT. Angiogenic, vascular injury and inflammatory cytokines are elevated in VAT versus SAT, indicating that VAT may promote inflammation, linked to regulating treatment response.

Impact of COVID-19 on the Diagnosis and Surgical Treatment of Colorectal Cancer: A National Perspective

Supplemental Digital Content is available in the text.

628 Management of Chyle Leaks Following Oesophagectomy: A Systematic Review

Aim

Chyle leakage is a rare but potentially life-threatening complication following oesophageal resection. The optimal management strategy is not clear.

Method

Searches were conducted up to 31/12/2020 on MEDLINE, Embase and Web of Science for randomised trials or retrospective studies that evaluated the management of chyle leakage following oesophageal resection. Two authors independently screened studies extracted data and assessed for bias. The protocol was prospectively registered on PROSPERO (CRD: 42021224895) and reported in accordance with PRISMA guidelines.

Results

A total of 530 citations were reviewed. Twenty-five studies, totaling 1016 patients met the inclusion criteria, including 2 low-quality clinical trials and 23 retrospective case series. Heterogeneity of study design and outcomes prevented meta-analysis. The overall incidence of chyle leaks was 3.2% but no consistent risk factors were found across studies. Eighteen studies describe management of chyle leaks conservatively, 17 by surgical ligation of the thoracic duct, and 6 described percutaneous lymphangiography with thoracic duct embolisation (TDE) or disruption (TDD). There is a paucity of high-quality prospective studies directly comparing treatment modalities, but there is some low-certainty evidence that percutaneous approaches have reduced morbidity, but lower efficacy compared to surgery.

Conclusions

The evidence-base for optimal management of chyle leakage post-oesophagectomy is lacking, which may be related to its low incidence. Further high quality, prospective studies that compare interventions at different levels of severity are needed to determine the optimal approach to treatment.

1438 The Past, Present and Future Management of Complex Chyle Fistulae

Background

Chyle leak/fistula is a rare complication of oesophageal surgery, usually consequent on an unintended breach of the thoracic duct, its tributaries, or the cisterna chyli. For high volume persistent leaks further surgery has been the traditional approach, however two cases have resulted in a new management approach at this Centre.

Case Series

The first patient, a 49-year-old, developed high volume drain output post three stage oesophagectomy. His jejunostomy feeding was discontinued, total parenteral nutrition and a somatostatin analogue, were commenced. Despite these measures, the drain output remained &gt;1.5litres per day and an exploratory thoracotomy was performed. The second patient, an 81-year-old underwent a transhiatal-oesophagectomy. On postoperative day 10 he developed acute onset shortness of breath, CXR demonstrated a large left sided pleural effusion. CT thorax demonstrated multiloculated complex pleural effusions. US guided pig tail drain was placed in the largest targetable effusion. The fluid was chylous in appearance. In both cases, an interventional radiological approach, not previously performed at this centre, provided definitive management. Lymphangiography was performed via injection of 1mL of Lipoidol® every 5 minutes into the inguinal lymph nodes to identify the cisterna chyli. A guidewire was advanced via the cisterna chyli with coils and glue used to embolize the leaking tracts.

Discussion

The lessons from this experience provide an algorithm for the management of chyle leaks, that will change practice at this centre. Embolization or disruption of thoracic duct and cisterna chyli leaks will be first line therapy for complex chyle leaks, with surgery reserved for where this fails.

Chemokine-targeted therapies: An opportunity to remodel immune profiles in gastro-oesophageal tumours

Immunotherapies are transforming outcomes for many cancer patients and are quickly becoming the fourth pillar of cancer therapy. However, their efficacy of only ∼25% in gastro-oesophageal cancer has been disappointing. This is attributed to factors such as insufficient patient stratification and the pro-tumourigenic immune landscape of gastro-oesophageal tumours. The chemokine profiles of solid tumours and the availability of effector immune cells greatly influence the immune infiltrate, producing 'cold' or 'immune-excluded' tumours in which immunotherapies are unable to reinvigorate the immune response. Other biological functions for chemokines have emerged, such as promoting cell survival, polarising T cell responses, and supporting several hallmarks of cancer. Therefore, chemokine networks may be exploited with therapeutic intent to mobilise and polarise anti-tumour immune cells, with further utility as combination treatments to augment the efficacy of current cancer immunotherapies. Few studies have demonstrated the clinical benefit of chemokine-targeted therapies as monotherapies, and this review proposes their consideration as combination treatments. Herein, we explore the anti-tumour and pro-tumour implications of chemokine signalling in gastro-oesophageal cancer and discuss their value as prognostic and predictive biomarkers in response to treatment.

Body composition is associated with operative and oncologic outcomes in the management of retroperitoneal and trunk soft tissue sarcoma

BACKGROUND

Sarcopenia, myosteatosis and obesity in cancer may confer negative clinical outcomes, but their prevalence and impact among patients with retroperitoneal and trunk soft tissue sarcoma have not been systematically studied. The aim of this study was to determine body composition among patients with retroperitoneal and trunk sarcoma, and assess impact on operative and oncologic outcomes.

METHODS

Consecutive patients undergoing treatment with curative intent from 2009 to 2019 were studied. Subcutaneous fat area and visceral fat areas, intramuscular adipose, lean body mass and fat mass were determined at diagnosis by CT at L3. Univariable and multivariable linear, logistic and Cox proportional hazards regression were performed.

RESULTS

95 patients (43.2% retroperitoneal, 48.4% trunk, 46.3% multivisceral resection) were studied. Visceral obesity was evident in 47.4%. Postoperative morbidity occurred in 25.9%, with preoperative radiotherapy (OR10.53 [95% CI 1.08-102.39], P = 0.042) and fat mass (OR1.41 [1.12-1.79], P = 0.004) independently predictive on multivariable analysis, while intramuscular adipose independently predicted inpatient LOS (P < 0.001), wound infection (P = 0.024, OR1.20 [1.02-1.40]) and major postoperative morbidity (P = 0.027, OR1.15 [1.02-1.31]). Increasing fat mass, subcutaneous fat area and intramuscular adipose were associated with greater tumor size (all P < 0.01), while intramuscular adipose predicted disease progression during neoadjuvant therapy (P = 0.024), and independently predicted disease specific survival (DSS) (P = 0.005, HR1.11 [1.03-1.20]) and overall survival (OS) on multivariable analysis (P < 0.001, HR1.19 [1.08-1.31]).

CONCLUSION

Visceral obesity is common in retroperitoneal and trunk sarcoma, and measures of adiposity are associated with adverse operative, but not oncologic outcomes. Myosteatosis is independently associated with postoperative morbidity and adverse oncologic outcomes. Body composition may represent a marker of risk among patients with retroperitoneal and trunk sarcoma.