The microbial composition of pancreatic ductal adenocarcinoma: A systematic review of 16S rRNA gene sequencing.

BACKGROUND: Pancreatic cancer, specifically pancreatic ductal adenocarcinoma (PDAC), continues to pose a significant clinical and scientific challenge. The most significant finding of recent years is that PDAC tumours harbour their specific microbiome, which differs amongst tumour entities and is distinct from healthy tissue. This review aims to evaluate and summarise all PDAC studies that have used the next-generation technique, 16S rRNA gene amplicon sequencing within each bodily compartment. As well as establishing a causal relationship between PDAC and the microbiome. MATERIALS AND METHODS: This systematic review was carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. A comprehensive search strategy was designed, and 1727 studies were analysed. RESULTS: In total, 38 studies were selected for qualitative analysis and summarised significant PDAC bacterial signatures. Despite the growing amount of data provided, we are not able to state a universal 16S rRNA gene microbial signature that can be used for PDAC screening. This is most certainly due to the heterogeneity of the presentation of results, lack of available datasets and the intrinsic selection bias between studies. CONCLUSION: Several key studies have begun to shed light on causality and the influence the microbiome constituents and their produced metabolites could play in tumorigenesis and influencing outcomes. The challenge in this field is to shape the available microbial data into targetable signatures. Making sequenced data readily available is critical, coupled with the coordinated standardisation of data and the need for consensus guidelines in studies investigating the microbiome in PDAC.

Improving Environmental Sustainability of Operating Theatres: A Systematic Review of Staff Attitudes, Barriers, and Enablers.

OBJECTIVE: To understand views of staff in relation to attitudes, enablers, and barriers to implementation of environmentally sustainable surgery in operating theatres. This will ultimately help in the goal of successfully implementing more sustainable theatres. SUMMARY BACKGROUND: Global healthcare sectors are responsible for 4.4% of greenhouse gas emissions. Surgical operating theatres are resource intensive areas and improvements will be important to meet Net-Zero carbon emissions within healthcare. METHODS: Three databases were searched (Web of Science, Ovid and PubMed), last check January 2024. We included original manuscripts evaluating staff views regarding sustainable operating theatres. The Mixed Methods Appraisal Tool was used for quality appraisal and data analysed using thematic synthesis. RESULTS: 2933 articles were screened and 14 fulfilled inclusion criteria, using qualitative (1), quantitative (2), and mixed methods (11). Studies were undertaken in a variety of clinical (Department of Anaesthesia, Surgery, Otolaryngology, Obstetrics & Gynaecology and Ophthalmology) and geographical settings (Australia, Canada, France, Germany, New Zealand, USA, UK & Ireland,). Across studies there was a lack of evidence exploring enablers to implementation, but barriers mainly related to the following themes: education and awareness, leadership, resistance to change, facilities and equipment, time, and incentive. CONCLUSION: This systematic review identified attitudes and barriers perceived by clinicians towards improving environmental sustainability within operating theatres, which may inform future strategy towards sustainable surgery. Most studies used a survey-design, whereas use of interviews may provide deeper insights. Future work should be extended to wider stakeholders influencing operating theatres. Additionally, implementation studies should be carried out to examine whether barriers do change in practice. This systematic review identified attitudes and barriers perceived by clinicians towards improving environmental sustainability within operating theatres, which may inform future strategy towards sustainable surgery. Most studies used a survey-design, whereas use of interviews may provide deeper insights. Future work should be extended to wider stakeholders influencing operating theatres. Additionally, implementation studies should be carried out to examine whether barriers do change in practice.

Impact of tertiary lymphoid structures on prognosis and therapeutic response in pancreatic ductal adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is known to have a heterogeneous desmoplastic tumour microenvironment (TME) with a large number of immunosuppressive cells. Recently, high B-cell infiltration in PDAC has received growing interest as a potential therapeutic target. METHODS: Our literature review summarises the characteristics of tumour-associated tertiary lymphoid structures (TLSs) and highlight the key studies exploring the clinical outcomes of TLSs in PDAC patients and the direct effect on the TME. RESULTS: The location, density and maturity stages of TLSs within tumours play a key role in determining the prognosis and is a new emerging target in cancer immunotherapy. DISCUSSION: TLS development is imperative to improve the prognosis of PDAC patients. In the future, studying the genetics and immune characteristics of tumour infiltrating B cells and TLSs may lead towards enhancing adaptive immunity in PDAC and designing personalised therapies.

Bile Microbiome Signatures Associated with Pancreatic Ductal Adenocarcinoma Compared to Benign Disease: A UK Pilot Study.

Pancreatic ductal adenocarcinoma (PDAC) has a very poor survival. The intra-tumoural microbiome can influence pancreatic tumourigenesis and chemoresistance and, therefore, patient survival. The role played by bile microbiota in PDAC is unknown. We aimed to define bile microbiome signatures that can effectively distinguish malignant from benign tumours in patients presenting with obstructive jaundice caused by benign and malignant pancreaticobiliary disease. Prospective bile samples were obtained from 31 patients who underwent either Endoscopic Retrograde Cholangiopancreatography (ERCP) or Percutaneous Transhepatic Cholangiogram (PTC). Variable regions (V3-V4) of the 16S rRNA genes of microorganisms present in the samples were amplified by Polymerase Chain Reaction (PCR) and sequenced. The cohort consisted of 12 PDAC, 10 choledocholithiasis, seven gallstone pancreatitis and two primary sclerosing cholangitis patients. Using the 16S rRNA method, we identified a total of 135 genera from 29 individuals (12 PDAC and 17 benign). The bile microbial beta diversity significantly differed between patients with PDAC vs. benign disease (Permanova p = 0.0173). The separation of PDAC from benign samples is clearly seen through unsupervised clustering of Aitchison distance. We found three genera to be of significantly lower abundance among PDAC samples vs. benign, adjusting for false discovery rate (FDR). These were Escherichia (FDR = 0.002) and two unclassified genera, one from Proteobacteria (FDR = 0.002) and one from Enterobacteriaceae (FDR = 0.011). In the same samples, the genus Streptococcus (FDR = 0.033) was found to be of increased abundance in the PDAC group. We show that patients with obstructive jaundice caused by PDAC have an altered microbiome composition in the bile compared to those with benign disease. These bile-based microbes could be developed into potential diagnostic and prognostic biomarkers for PDAC and warrant further investigation.

The Role of the Multiparametric MRI LiverMultiScanTM in the Quantitative Assessment of the Liver and Its Predicted Clinical Applications in Patients Undergoing Major Hepatic Resection for Colorectal Liver Metastasis.

Liver biopsy remains the gold standard for the histological assessment of the liver. With clear disadvantages and the rise in the incidences of liver disease, the role of neoadjuvant chemotherapy in colorectal liver metastasis (CRLM) and an explosion of surgical management options available, non-invasive serological and imaging markers of liver histopathology have never been more pertinent in order to assess liver health and stratify patients considered for surgical intervention. Liver MRI is a leading modality in the assessment of hepatic malignancy. Recent technological advancements in multiparametric MRI software such as the LiverMultiScanTM offers an attractive non-invasive assay of anatomy and histopathology in the pre-operative setting, especially in the context of CRLM. This narrative review examines the evidence for the LiverMultiScanTM in the assessment of hepatic fibrosis, steatosis/steatohepatitis, and potential applications for chemotherapy-associated hepatic changes. We postulate its future role and the hurdles it must surpass in order to be implemented in the pre-operative management of patients undergoing hepatic resection for colorectal liver metastasis. Such a role likely extends to other hepatic malignancies planned for resection.

Cancer cell-derived extracellular vesicles activate hepatic stellate cells in colorectal cancer.

Colorectal cancer (CRC) is the 2nd leading cause of cancer-related deaths worldwide, primarily due to the development of metastatic disease. The liver is the most frequently affected site. The metastatic cascade relies on a complex interaction between the immune system, tumor, and distant organs. Communication between the tumor and the metastatic site can be mediated by tumor-derived extracellular vesicles (EVs) and their cargo. The mechanisms underlying this process are starting to be understood through research that has rapidly expanded over the past 15 years. One crucial aspect is the remodeling of the microenvironment at the site of metastasis, which is essential for the formation of a premetastatic niche and the subsequent establishment of metastatic deposits. In the evaluated study, the authors use cellular experiments and a mouse model to investigate how tumour derived extracellular vesicles and their microRNA contents interact with hepatic stellate cells (HSCs). They demonstrate how this may lead to remodelling of the microenvironment and the formation of colorectal liver metastasis using their experimental model. In this mini review, we examine the current evidence surrounding tumour derived EVs and their effect on the tumour microenvironment to highlight potential areas for future research in CRC and other malignancies.

A Comprehensive Review of the Current and Future Role of the Microbiome in Pancreatic Ductal Adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is expected to become the second most common cause of cancer death in the USA by 2030, yet progress continues to lag behind that of other cancers, with only 9% of patients surviving beyond 5 years. Long-term survivorship of PDAC and improving survival has, until recently, escaped our understanding. One recent frontier in the cancer field is the microbiome. The microbiome collectively refers to the extensive community of bacteria and fungi that colonise us. It is estimated that there is one to ten prokaryotic cells for each human somatic cell, yet, the significance of this community in health and disease has, until recently, been overlooked. This review examines the role of the microbiome in PDAC and how it may alter survival outcomes. We evaluate the possibility of employing microbiomic signatures as biomarkers of PDAC. Ultimately this review analyses whether the microbiome may be amenable to targeting and consequently altering the natural history of PDAC.

Multimodal Prehabilitation During Neoadjuvant Therapy Prior to Esophagogastric Cancer Resection: Effect on Cardiopulmonary Exercise Test Performance, Muscle Mass and Quality of Life-A Pilot Randomized Clinical Trial.

BACKGROUND: Neoadjuvant therapy reduces fitness, muscle mass, and quality of life (QOL). For patients undergoing chemotherapy and surgery for esophagogastric cancer, maintenance of fitness is paramount. This study investigated the effect of exercise and psychological prehabilitation on anaerobic threshold (AT) at cardiopulmonary exercise testing (CPET). Secondary endpoints included peak oxygen uptake (peak VO2), skeletal muscle mass, QOL, and neoadjuvant therapy completion. METHODS: This parallel-arm randomized controlled trial assigned patients with locally advanced esophagogastric cancer to receive prehabilitation or usual care. The 15-week program comprised twice-weekly supervised exercises, thrice-weekly home exercises, and psychological coaching. CPET was performed at baseline, 2 weeks after neoadjuvant therapy, and 1 week preoperatively. Skeletal muscle cross-sectional area at L3 was analyzed on staging and restaging computed tomography. QOL questionnaires were completed at baseline, mid-neoadjuvant therapy, at restaging laparoscopy, and postoperatively at 2 weeks, 6 weeks and 6 months. RESULTS: Fifty-four participants were randomized (prehabilitation group, n = 26; control group, n = 28). No difference in AT between groups was observed post-neoadjuvant therapy. Prehabilitation resulted in an attenuated peak VO2 decline {-0.4 [95% confidence interval (CI) -0.8 to 0.1] vs. -2.5 [95% CI -2.8 to -2.2] mL/kg/min; p = 0.022}, less muscle loss [-11.6 (95% CI -14.2 to -9.0) vs. -15.6 (95% CI -18.7 to -15.4) cm2/m2; p = 0.049], and improved QOL. More prehabilitation patients completed neoadjuvant therapy at full dose [prehabilitation group, 18 (75%) vs. control group, 13 (46%); p = 0.036]. No adverse events were reported. CONCLUSIONS: This study has demonstrated some retention of cardiopulmonary fitness (peak VO2), muscle, and QOL in prehabilitation subjects. Further large-scale trials will help determine whether these promising findings translate into improved clinical and oncological outcomes. Trial Registration ClinicalTrials.gov NCT02950324.

The Role of Circular RNAs in Pancreatic Ductal Adenocarcinoma and Biliary-Tract Cancers.

Pancreatic Ductal Adenocarcinoma (PDAC) and biliary-tract cancers (BTC) often present at a late stage, and consequently patients have poor survival-outcomes. Circular RNAs (circRNAs) are non-coding RNA molecules whose role in tumourigenesis has recently been realised. They are stable, conserved and abundant, with tissue-specific expression profiles. Therefore, significant interest has arisen in their use as potential biomarkers for PDAC and BTC. High-throughput methods and more advanced bioinformatic techniques have enabled better profiling and progressed our understanding of how circRNAs may function in the competing endogenous RNA (ceRNA) network to influence the transcriptome in these cancers. Therefore, the aim of this systematic review was to describe the roles of circRNAs in PDAC and BTC, their potential as biomarkers, and their function in the wider ceRNA network in regulating microRNAs and the transcriptome. Medline, Embase, Scopus and PubMed were systematically reviewed to identify all the studies addressing circRNAs in PDAC and BTC. A total of 32 articles were included: 22 considering PDAC, 7 for Cholangiocarcinoma (CCA) and 3 for Gallbladder Cancer (GBC). There were no studies investigating Ampullary Cancer. Dysregulated circRNA expression was associated with features of malignancy in vitro, in vivo, and ex vivo. Overall, there have been very few PDAC and BTC tissues profiled for circRNA signatures. Therefore, whilst the current studies have demonstrated some of their functions in these cancers, further work is required to elucidate their potential role as cancer biomarkers in tissue, biofluids and biopsies.

3D laparoscopy does not reduce operative duration or errors in day-case laparoscopic cholecystectomy: a randomised controlled trial.

BACKGROUND: Contemporary 3D platforms have overcome past deficiencies. Available trainee and laboratory studies suggest stereoscopic imaging improves performance but there is little clinical data or studies assessing specialists. We aimed to determine whether stereoscopic (3D) laparoscopic systems reduce operative time and number of intraoperative errors during specialist-performed laparoscopic cholecystectomy (LC). METHODS: A parallel arm (1:1) randomised controlled trial comparing 2D and 3D passive-polarised laparoscopic systems in day-case LC using was performed. Eleven consultant surgeons that had each performed > 200 LC (including > 10 3D LC) participated. Cases were video recorded and a four-point difficulty grade applied. The primary outcome was overall operative time. Subtask time and the number of intraoperative consequential errors as identified by two blinded assessors using a hierarchical task analysis and the observational clinical human reliability analysis technique formed secondary endpoints. RESULTS: 112 patients were randomised. There was no difference in operative time between 2D and 3D LC (23:14 min (± 10:52) vs. 20:17 (± 9:10), absolute difference - 14.6%, p = 0.148) although 3D surgery was significantly quicker in difficulty grade 3 and 4 cases (30:23 min (± 9:24), vs. 18:02 (± 7:56), p < 0.001). No differences in overall error count was seen (total 47, median 1, range 0-4 vs. 45, 1, 0-3, p = 0.62) although there were significantly fewer 3D gallbladder perforations (15 vs. 6, p = 0.034). CONCLUSION: 3D laparoscopy did not reduce overall operative time or error frequency in laparoscopic cholecystectomies performed by specialist surgeons. 3D reduced Calot's dissection time and operative time in complex cases as well as the incidence of iatrogenic gallbladder perforation (NCT01930344).

Is there still a role for the surgeon in the management of gastrointestinal bleeding ?

Modern investigation of gastrointestinal bleeds allows for reliable source identification in most cases. Current treatment algorithms utilise therapeutic endoscopy or interventional radiology and surgery now plays a limited role in the treatment of gastrointestinal bleeds. Approximately 2-4% of patients admitted with GI bleeds, however, require surgery to control their haemorrhage.

Surgical steps for standard laparoscopic low anterior resection.

Once considered an incurable disease, the continuous evolution of technologies and techniques has improved both oncological outcomes and quality of life for patients with rectal cancer. Multiport laparoscopic surgery for rectal cancer is the standard of care in many institutions and countries and is the approach that has been most subjected to controlled trial. Following a number of randomized trials as well as large series and registry reports and several Cochrane reviews, there is no evidence of any oncological disadvantage to laparoscopic surgery compared with the open approach and there is good evidence of improved short-term outcomes and some evidence of improved long-term outcomes. We describe the "standard" approach to multiport, laparoscopic low anterior resection.

Quality of life in the first 6 weeks following laparoscopic and open colorectal surgery.

OBJECTIVES: Evidence of how health-related quality of life (HRQOL) changes following laparoscopic and open colorectal surgery in the first 6 weeks of postoperative recovery is needed to inform cost-effectiveness evaluations. METHODS: Pragmatic prospective cohort study design. Consecutive patients requiring elective colorectal surgery were allocated to either laparoscopic or open surgery by administrative staff in a district general hospital in England, 2006-2007. Patients completed two validated, generic measures of HRQOL at baseline (preoperatively) and on multiple occasions in the first 6 weeks postsurgery using diaries (EuroQol five-dimensional [EQ-5D] questionnaire: 16 times; short-form 36 health survey [SF-36]: 4 times; HRQOL was compared between groups at each time point, and overall using repeated-measures analysis. RESULTS: Of 201 consecutive patients recruited, 32 (15.1%) were unable to complete diaries. Of the remaining 169 patients, 120 (71%) returned completed diaries at 28 days and 105 (62.1%) at 42 days. There was no difference in preoperative HRQOL scores between surgical groups, but the postoperative EQ-5D questionnaire and SF-36 scores were significantly higher in the laparoscopic group (EQ-5D questionnaire P = 0.005, SF-36 P = 0.007). Subgroup analysis showed that patients with a stoma have worse HRQOL than those without. HRQOL did not differ between the laparoscopic and open stoma patients. CONCLUSIONS: This study presents unique prospective data demonstrating that laparoscopic surgery confers HRQOL benefits for patients in the early recovery period following colorectal surgery, compared with open surgery. Consideration of these data in the context of a cost-effectiveness analysis will be reported separately.

Is competency assessment at the specialist level achievable? A study for the national training programme in laparoscopic colorectal surgery in England.

OBJECTIVES: To develop, validate, and implement a competency assessment tool (CAT) for technical surgical performance in the context of a summative assessment process for the National Training Programme in Laparoscopic Colorectal Surgery (NTP). BACKGROUND: The NTP is an educational initiative by the National Cancer Action Team in England to safely increase the uptake of laparoscopic colorectal surgery. It is the first competency-based national educational initiative for specialist surgeons (consultants), and performance assessment is an integral part of the program. METHODS: Content validity was sought using expert opinion by semistructured interviews and the Delphi method. For validity and reliability studies, NTP apprentices and experts were asked to submit video-recorded cases. Construct validity was established between delegates who passed the assessment and those who failed. Concurrent validity was tested by comparing scores with error counts as identified by observational clinical human reliability analysis. A fully crossed design, using generalizability theory methods and D-studies, was used for reliability. FINDINGS: Interviews and the Delphi method revealed a list of characteristics for assessment. A hybrid structure combining task-specific and generic items was used to include important characteristics into the assessment format. Fifty-four cases were submitted. Overall reliability reached G(ACI) = 0.803 when using 2 cases and 2 assessors. Experts scored significantly better than apprentices (3.19 vs 2.60; P = 0.004), and apprentices who passed had better scores than those who failed (2.95 vs 2.28; P < 0.001). There was an inverse correlation between CAT scores and observational clinical human reliability analysis error counts (ρ = -0.520, P < 0.001). The combination of both methods reached overall sensitivity of 100%, specificity of 83.3%, a positive predictive value of 93.8%, and a negative predictive value of 100%. CONCLUSIONS: The CAT can reliably assess technical performance in laparoscopic colorectal surgery. The use of CATs to judge specialist technical performance before embarking on independent practice of new procedures is achievable on a national scale and can be adapted by other specialties.

Predictive and prognostic factors in colorectal cancer: a personalized approach.

It is an exciting time for all those engaged in the treatment of colorectal cancer. The advent of new therapies presents the opportunity for a personalized approach to the patient. This approach considers the complex genetic mechanisms involved in tumorigenesis in addition to classical clinicopathological staging. The potential predictive and prognostic biomarkers which have stemmed from the study of the genetic basis of colorectal cancer and therapeutics are discussed with a focus on mismatch repair status, KRAS, BRAF, 18qLOH, CIMP and TGF-ß.

Systematic review of the costs of laparoscopic colorectal surgery.

PURPOSE: Recent studies have confirmed the clinical efficacy of laparoscopic colorectal surgery; however, its use has not become widespread. One reason for this is perceived economic implications. A systematic review was undertaken examining the costs of laparoscopic colorectal surgery. METHODS: Electronic databases were searched for articles comparing laparoscopic colorectal surgery and open surgery. Primary outcome measures were operating room, direct hospital, and indirect costs. Secondary outcomes were conversion rates and length of hospital stay. The percentage difference in costs was used for comparisons between studies. RESULTS: Twenty-nine articles were identified in which cost data were presented (total number of patients 3,681); the economic data in most studies was limited. Operating room costs were greater for laparoscopic colorectal surgery than open surgery in all studies (median difference, 50 percent; interquartile range, 27-78 percent; P < 0.001). There was no overall difference in total hospital costs (median difference, 0 percent; interquartile range, -17.5 to 21 percent). Only two articles collected data on indirect costs, with both in favor of laparoscopic colorectal surgery. Hospital stay was shorter for laparoscopic colorectal surgery in all studies (median difference, 2.8 days; interquartile range, 1.3-3.7; P < 0.001). Median conversion rate was 7.8 percent (mean, 14 percent; interquartile range, 6-21 percent). CONCLUSIONS: Operating room costs are greater for laparoscopic colorectal surgery than open surgery. Total hospital costs are similar. There may be societal benefits associated with lower indirect costs for laparoscopic colorectal surgery. Cost should not be a deterrent to performing laparoscopic colorectal surgery.