Vagal Sparing Gastrectomy: A Systematic Review and Meta-Analysis.

INTRODUCTION: Radical gastrectomy is associated with significant functional complications. In appropriate patients may be amenable to less invasive resection aimed at preserving the vagal trunks. The aim of this systematic review and meta-analysis was to assess the functional consequences and oncological safety of vagal sparing gastrectomy (VSG) compared to conventional non-vagal sparing gastrectomy (CG). METHODS: A systematic review of four databases in accordance with PRISMA guidelines was undertaken for studies published between January 1, 1990, and December 15, 2021, comparing patients who underwent VSG to CG. We meta-analysed the following outcomes: operative time, blood loss, nodal yield, days to flatus, body weight changes, as well as the incidence of post-operative cholelithiasis, diarrhoea, delayed gastric emptying, and dumping syndrome. RESULTS: Thirty studies were included in the meta-analysis with a selection of studies qualitatively analysed. VSG was associated with a lower rate of cholelithiasis (OR: 0.25, 95% CI: 0.15-0.41, p < 0.010) and early dumping syndrome (OR: 0.42, 95% CI: 0.21-0.86; p = 0.02), less blood loss (mean difference [MD]: -51 mL, 95% CI: -89.11 to -12.81 mL, p = 0.009), less long-term weight loss (MD: 2.03%, 95% CI: 0.31-3.76%, p = 0.02) and a faster time to flatus (MD: -0.42 days, 95% CI: -0.48 to 0.36, p < 0.001). There was no significant difference in nodal harvest, overall survival, and all other endpoints. CONCLUSION: VSG significantly reduces the incidence of post-operative cholelithiasis and dumping syndrome, decreases weight loss, and facilitates an earlier return of gut motility. Although technically more challenging, VSG should be considered for prophylactic surgery.

Para-conduit diaphragmatic hernia following esophagectomy-the new price of minimally invasive surgery?

Esophageal Cancer is the seventh commonest cancer worldwide with poor overall survival. Significant morbidity related to open esophagectomy has driven practice toward hybrid, totally minimally invasive and robotic procedures. With the increase in minimally invasive approaches, it has been suggested that there might be an increased incidence of subsequent para-conduit diaphragmatic hernia. To assess the incidence, modifiable risk factors and association with operative approach of this emerging complication, we evaluated outcomes following esophagectomy from two Australian Centers. Prospectively collected databases were examined to identify patients who developed versus did not develop a para-conduit hernia. Patient characteristics, disease factors, treatment factors, operative and post-operative factors were compared for these two groups. A total of 24 of 297 patients who underwent esophagectomy were diagnosed with a symptomatic para-conduit diaphragmatic hernia (8.1%). The significant risk factor for hernia was a minimally invasive abdominal approach (70.8% vs. 35.5%; P = 0.004, odds ratio = 12.876, 95% CI 2.214-74.89). Minimally invasive thoracic approaches were not associated with increased risk. Minimally invasive abdominal approaches to esophagectomy doubled the risk of developing a para-conduit diaphragmatic hernia. Effective operative solutions to address this complication are required.

Optimal Timing of Perioperative Chemical Thromboprophylaxis in Elective Major Abdominal Surgery: A Systematic Review and Meta-analysis.

OBJECTIVE: To investigate the effect of the timing of chemoprophylaxis on venous thromboembolisms (VTEs) and bleeding rates in patients undergoing major abdominal surgery. BACKGROUND: Postoperative bleeding and VTE incur significant morbidity, mortality, and health care costs. Chemoprophylaxis is used routinely to prevent VTEs but increases bleeding risk. The perioperative timing of chemoprophylaxis initiation may influence both VTE and bleeding risks. The optimal window for commencing chemoprophylaxis in the perioperative period is unclear. METHODS: MEDLINE, EMBASE, Cochrane Library, and Web of Science databases were searched using PRISMA guidelines. Randomized trials and cohort studies published between January 1, 2000 to May 10, 2022, which reported on chemoprophylaxis timing as well as the incidence of VTE and bleeding after elective abdominal surgery were meta-analyzed. RESULTS: From 6175 studies, 14 (24,922 patients) were meta-analyzed. Bariatric (4 studies), antireflux (1 study), hepato-pancreatic-biliary (5 studies), colorectal (1 study), ventral hernia (1 study), and major intra-abdominal surgeries (2 studies) were included. Chemoprophylaxis was initiated before skin closure in 10,403 patients, and postoperatively in 14,519 patients. Both symptomatic [risk ratios (RR), 0.81; 95% CI, 0.45-1.43; P =0.460] and overall (RR, 0.74; 95% CI, 0.45-1.24; P =0.250) VTE rates were comparable between study groups. Compared with postoperative chemoprophylaxis, early usage increased the risk of all bleeding (RR, 1.56; 95% CI, 1.13-2.15; P =0.007), major bleeding (RR, 1.63; 95% CI, 1.16-2.28; P =0.005), blood transfusion (RR, 1.48; 95% CI, 1.24-1.76; P <0.001), and reintervention (RR, 1.94; 95% CI, 1.19-3.18; P =0.008). CONCLUSIONS: Our findings advocate for initiating chemoprophylaxis postoperatively in elective abdominal surgery to minimize bleeding risk without compromising VTE protection.

Tumor-Infiltrating Neutrophils after Neoadjuvant Therapy are Associated with Poor Prognosis in Esophageal Cancer.

BACKGROUND: In esophageal cancer (EC), there is a paucity of knowledge regarding the interplay between the tumor immune microenvironment and response to neoadjuvant treatment and, therefore, which factors may influence outcomes. Thus, our goal was to investigate the changes in the immune microenvironment with neoadjuvant treatment in EC by assessing the expression of immune related genes and their association with prognosis. METHODS: We examined the transcriptome of paired pre- and post-neoadjuvant treated EC specimens. Based on these findings, we validated the presence of tumor-infiltrating neutrophils using CD15+ immunohistochemistry in a discovery cohort of patients with residual pathologic disease. We developed a nomogram as a predictor of progression-free survival (PFS) incorporating the variables CD15+ cell count, tumor regression grade, and tumor grade. RESULTS: After neoadjuvant treatment, there was an increase in genes related to myeloid cell differentiation and a poor prognosis associated with high neutrophil (CD15+) counts. Our nomogram incorporating CD15+ cell count was predictive of PFS with a C-index of 0.80 (95% confidence interval [CI] 0.68-0.9) and a concordance probability estimate (CPE) of 0.77 (95% CI 0.69-0.86), which indicates high prognostic ability. The C-index and CPE of the validation cohort were 0.81 (95% CI 0.69-0.91) and 0.78 (95% CI 0.7-0.86), respectively. CONCLUSIONS: Our nomogram incorporating CD15+ cell count can potentially be used to identify patients at high risk of recurrent disease and thus stratify patients who will benefit most from adjuvant treatment.

Eprenetapopt triggers ferroptosis, inhibits NFS1 cysteine desulfurase, and synergizes with serine and glycine dietary restriction.

The mechanism of action of eprenetapopt (APR-246, PRIMA-1MET) as an anticancer agent remains unresolved, although the clinical development of eprenetapopt focuses on its reported mechanism of action as a mutant-p53 reactivator. Using unbiased approaches, this study demonstrates that eprenetapopt depletes cellular antioxidant glutathione levels by increasing its turnover, triggering a nonapoptotic, iron-dependent form of cell death known as ferroptosis. Deficiency in genes responsible for supplying cancer cells with the substrates for de novo glutathione synthesis (SLC7A11, SHMT2, and MTHFD1L), as well as the enzymes required to synthesize glutathione (GCLC and GCLM), augments the activity of eprenetapopt. Eprenetapopt also inhibits iron-sulfur cluster biogenesis by limiting the cysteine desulfurase activity of NFS1, which potentiates ferroptosis and may restrict cellular proliferation. The combination of eprenetapopt with dietary serine and glycine restriction synergizes to inhibit esophageal xenograft tumor growth. These findings reframe the canonical view of eprenetapopt from a mutant-p53 reactivator to a ferroptosis inducer.

Prophylactic negative pressure wound dressings reduces wound complications following emergency laparotomies: A systematic review and meta-analysis.

BACKGROUND: Wound complications are a common cause of postoperative morbidity and incur significant healthcare costs. Recent studies have shown that negative pressure wound dressings reduce wound complication rates, particularly surgical site infections, after elective laparotomies. The clinical utility of prophylactic negative pressure wound dressings for closed emergency laparotomy incisions remains controversial. This meta-analysis investigated the rates of wound complications after emergency laparotomy when a negative pressure wound dressing was applied. METHODS: A systematic review and meta-analysis were performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed, Embase, Cochrane Registry, Web of Science, and Clinialtrials.gov databases were searched from January 1, 2005, to April 1, 2022. All studies comparing negative pressure wound dressings to standard dressings on closed emergency laparotomy incisions were included. RESULTS: A total of 1,199 (negative pressure wound dressings: 566, standard dressing: 633) patients from 7 (prospective: 4, retrospective: 3) studies were identified. Overall, the surgical site infection (superficial/deep) rate was 13.6% (77/566) vs 25.1% (159/633) in the negative pressure wound dressing versus standard dressing groups, respectively (odds ratio 0.43, 95% confidence interval 0.30-0.62). Wound breakdown (skin/fascial dehiscence) was significantly lower in the negative pressure wound dressing (7.7%) group compared to the standard dressing (16.9%) group (odds ratio 0.36, 95% confidence interval 0.19-0.72). The incidence of overall wound complications was significantly lower in the negative pressure wound dressing (15.9%) group compared to the standard dressing (30.4%) group (odds ratio 0.41, 95% confidence interval 0.28-0.59). No significant differences were found in hospital length-of-stay and readmission rates. CONCLUSION: Prophylactic negative pressure wound dressings for closed emergency laparotomy incisions were associated with a significant reduction in surgical site infections, wound breakdown, and overall wound complications, thus supporting its clinical use.

Potential Clinical Utility of a Targeted Circulating Tumor DNA Assay in Esophageal Adenocarcinoma.

OBJECTIVE: To explore the clinical utility of circulating tumor DNA (ctDNA) in esophageal adenocarcinoma (EAC) by developing a cost-effective and rapid technique utilising targeted amplicon sequencing. SUMMARY OF BACKGROUND DATA: Emerging evidence suggests that levels of ctDNA in the blood can be used to monitor treatment response and in the detection of disease recurrence in various cancer types. Current staging modalities for EAC such as computerised tomography of the chest/abdomen/pelvis (CT) and positron emission tomography (PET) do not reliably detect occult micro-metastatic disease, the presence of which signifies a poor prognosis. After curative-intent treatment, some patients are still at high risk of recurrent disease, and there is no widely accepted optimal surveillance tool for patients with EAC. METHODS: Sixty-two patients with EAC were investigated for the presence of ctDNA using a tumor-informed approach. We designed a custom targeted amplicon sequencing panel of target specific primers covering mutational foci in 9 of the most commonly mutated genes in EAC. Serial blood samples were taken before and after neoadjuvant treatment (NAT), and during surveillance. RESULTS: Somatic mutations were detected in pre-treatment biopsy samples of 55 out of 62 (89%) EAC patients. Mutations in TP53 (80%) were the most common. Out of these 55 patients, 20 (36%) had detectable ctDNA at baseline. The majority (90%) of patients with detectable ctDNA had either locally advanced tumors, nodal involvement or metastatic disease. In patients with locally advanced tumors, disease free survival (DFS) was more accurately stratified using pre-treatment ctDNA status [HR 4.34 (95% CI 0.93-20.21); P = 0.05] compared to nodal status on PET-CT. In an exploratory subgroup analysis, patients who are node negative but ctDNA positive have inferior DFS [HR 11.71 (95% CI 1.16-118.80) P = 0.04]. In blood samples taken before and following NAT, clearance of ctDNA after NAT was associated with a favourable response to treatment. Furthermore, patients who are ctDNA positive during post-treatment surveillance are at high risk of relapse. CONCLUSIONS: Our study shows that ctDNA has potential to provide additional prognostication over conventional staging investigation such as CT and PET. It may also have clinical utility in the assessment of response to NAT and as a biomarker for the surveillance of recurrent disease.

Increased risk of diaphragmatic herniation following esophagectomy with a minimally invasive abdominal approach.

OBJECTIVE: Diaphragmatic herniation is a rare complication following esophagectomy, associated with risks of aspiration pneumonia, bowel obstruction, and strangulation. Repair can be challenging due to the presence of the gastric conduit. We performed this systematic review and meta-analysis to determine the incidence and risk factors associated with diaphragmatic herniation following esophagectomy, the timing and mode of presentation, and outcomes of repair. METHODS: A systematic search using Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines was performed using four major databases. A meta-analysis of diaphragmatic herniation incidence following esophagectomies with a minimally invasive abdominal (MIA) approach compared with open esophagectomies was conducted. Qualitative analysis was performed for tumor location, associated symptoms, time to presentation, and outcomes of postdiaphragmatic herniation repair. RESULTS: This systematic review consisted of 17,052 patients from 32 studies. The risk of diaphragmatic herniation was 2.74 times higher in MIA esophagectomy compared with open esophagectomy, with pooled incidence of 6.0% versus 3.2%, respectively. Diaphragmatic herniation was more commonly seen following surgery for distal esophageal tumors. Majority of patients (64%) were symptomatic at diagnosis. Presentation within 30 days of operation occurred in 21% of cases and is twice as likely to require emergent repair with increased surgical morbidity. Early diaphragmatic herniation recurrence and cardiorespiratory complications are common sequelae following hernia repair. CONCLUSIONS: In the era of MIA esophagectomy, one has to be cognizant of the increased risk of diaphragmatic herniation and its sequelae. Failure to recognize early diaphragmatic herniation can result in catastrophic consequences. Increased vigilance and decreased threshold for imaging during this period is warranted.

Cyclooxygenases and Prostaglandins in Tumor Immunology and Microenvironment of Gastrointestinal Cancer.

Chronic inflammation is a known risk factor for gastrointestinal cancer. The evidence that nonsteroidal anti-inflammatory drugs suppress the incidence, growth, and metastasis of gastrointestinal cancer supports the concept that a nonsteroidal anti-inflammatory drug target, cyclooxygenase, and its downstream bioactive lipid products may provide one of the links between inflammation and cancer. Preclinical studies have demonstrated that the cyclooxygenase-2-prostaglandin E2 pathway can promote gastrointestinal cancer development. Although the role of this pathway in cancer has been investigated extensively for 2 decades, only recent studies have described its effects on host defenses against transformed epithelial cells. Overcoming tumor-immune evasion remains one of the major challenges in cancer immunotherapy. This review summarizes the impacts of the cyclooxygenase-2-prostaglandin E2 pathway on gastrointestinal cancer development. Our focus was to highlight recent advances in our understanding of how this pathway induces tumor immune evasion.

SLC7A11 Is a Superior Determinant of APR-246 (Eprenetapopt) Response than TP53 Mutation Status.

APR-246 (eprenetapopt) is in clinical development with a focus on hematologic malignancies and is promoted as a mutant-p53 reactivation therapy. Currently, the detection of at least one TP53 mutation is an inclusion criterion for patient selection into most APR-246 clinical trials. Preliminary results from our phase Ib/II clinical trial investigating APR-246 combined with doublet chemotherapy [cisplatin and 5-fluorouracil (5-FU)] in metastatic esophageal cancer, together with previous preclinical studies, indicate that TP53 mutation status alone may not be a sufficient biomarker for APR-246 response. This study aims to identify a robust biomarker for response to APR-246. Correlation analysis of the PRIMA-1 activity (lead compound to APR-246) with mutational status, gene expression, protein expression, and metabolite abundance across over 700 cancer cell lines (CCL) was performed. Functional validation and a boutique siRNA screen of over 850 redox-related genes were also conducted. TP53 mutation status was not consistently predictive of response to APR-246. The expression of SLC7A11, the cystine/glutamate transporter, was identified as a superior determinant of response to APR-246. Genetic regulators of SLC7A11, including ATF4, MDM2, wild-type p53, and c-Myc, were confirmed to also regulate cancer-cell sensitivity to APR-246. In conclusion, SLC7A11 expression is a broadly applicable determinant of sensitivity to APR-246 across cancer and should be utilized as the key predictive biomarker to stratify patients for future clinical investigation of APR-246.

Incremental diagnostic utility of gastric distension FDG PET/CT.

PURPOSE: To assess the diagnostic utility of gastric distension (GD) FDG PET/CT in both patients with known gastric malignancy and those not known to have gastric malignancy but with incidental focal FDG uptake in the stomach. METHODS: This retrospective analysis included 88 patients who underwent FDG PET/CT following GD with hyoscine N-butylbromide (Buscopan®) and water ingestion as part of routine clinical evaluation between 2004 and 2014. FDG PET/CT scans before and after GD were reported blinded to the patient clinical details in 49 patients undergoing pretreatment staging of gastric malignancy and 39 patients who underwent GD following incidental suspicious gastric uptake. The PET findings were validated by a composite clinical standard. RESULTS: In the 49 patients undergoing pretreatment staging of gastric malignancy, GD improved PET detection of the primary tumour (from 80 % to 90 %). PET evaluation of tumour extent was concordant with endoscopic/surgical reports in 31 % (interpreter 1) and 45 % (interpreter 2) using pre-GD images and 73 % and 76 % using GD images. Interobserver agreement also improved with GD (κ = 0.29 to 0.69). Metabolic and morphological quantitative analysis demonstrated a major impact of GD in normal gastric wall but no significant effect in tumour, except a minor increase in SUV related to a delayed acquisition time. The tumour to normal stomach SUVmax ratio increased from 3.8 ± 2.9 to 9.2 ± 8.6 (mean ± SD) with GD (p < 0.0001), facilitating detection and improved assessment of the primary tumour. In 25 (64 %) of the 39 patients with incidental suspicious gastric uptake, acquisition after GD correctly excluded a malignant process. In 10 (71 %) of the remaining 14 patients with persistent suspicious FDG uptake despite GD, malignancy was confirmed and in 3 (21 %) an active but benign pathology was diagnosed. CONCLUSION: GD is a simple way to improve local staging with FDG PET in patients with gastric malignancy. In the setting of incidental suspicious gastric uptake, GD is also an effective tool for ruling out malignancy and leads to the avoidance of unnecessary endoscopy.