Continuous drain irrigation as a risk mitigation strategy for postoperative pancreatic fistula: a meta-analysis.

BACKGROUND: Postoperative pancreatic fistula serves as the principle cause for the morbidity and mortality observed after pancreatectomy. Continuous drain irrigation as a treatment strategy for infected pancreatic necrosis has previously been described; however, its role adter pancreatectomy has yet to be determined. The aim of this study was to determine whether continuous drain irrigation reduces postoperative pancreatic fistula. METHODS: A meta-analysis of the pre-existing literature was performed. The primary end point was whether continuous drain irrigation reduced postoperative pancreatic fistula after pancreatectomy. The secondary end point evaluated its impact on postoperative morbidity, mortality, and length of stay. RESULTS: Nine articles involving 782 patients were included. Continuous drain irrigation use was associated with a statistically significant reduction in postoperative pancreatic fistula rates (odds ratio [95% confidence interval] 0.40 [0.19-0.82], P = .01). Upon subgroup analysis, a significant reduction in clinically relevant postoperative pancreatic fistula was also noted (odds ratio 0.37 [0.20-0.66], P = .0008). A reduction in postoperative complications was also observed-delayed gastric emptying (0.45 [0.24-0.84], P = .01) and the need for re-operation (0.33 [0.11-0.96], P = .04). This reduction in postoperative complications translated into a reduced length of stay (mean difference -2.62 [-4.97 to -0.26], P = .03). CONCLUSION: Continuous drain irrigation after pancreatectomy is a novel treatment strategy with a limited body of published evidence. After acknowledging the limitations of the data, initial analysis would suggest that it may serve as an effective risk mitigation strategy against postoperative pancreatic fistula. Further research in a prospective context utilizing patient risk stratification for fistula development is, however, required to define its role within clinical practice.

Impacts of combining anti-PD-L1 immunotherapy and radiotherapy on the tumour immune microenvironment in a murine prostate cancer model.

BACKGROUND: Radiotherapy enhances innate and adaptive anti-tumour immunity. It is unclear whether this effect may be harnessed by combining immunotherapy with radiotherapy fractions used to treat prostate cancer. We investigated tumour immune microenvironment responses of pre-clinical prostate cancer models to radiotherapy. Having defined this landscape, we tested whether radiotherapy-induced tumour growth delay could be enhanced with anti-PD-L1. METHODS: Hypofractionated radiotherapy was delivered to TRAMP-C1 and MyC-CaP flank allografts. Tumour growth delay, tumour immune microenvironment flow-cytometry, and immune gene expression were analysed. TRAMP-C1 allografts were then treated with 3 × 5 Gy ± anti-PD-L1. RESULTS: 3 × 5 Gy caused tumour growth delay in TRAMP-C1 and MyC-CaP. Tumour immune microenvironment changes in TRAMP-C1 at 7 days post-radiotherapy included increased tumour-associated macrophages and dendritic cells and upregulation of PD-1/PD-L1, CD8+ T-cell, dendritic cell, and regulatory T-cell genes. At tumour regrowth post-3 × 5 Gy the tumour immune microenvironment flow-cytometry was similar to control tumours, however CD8+, natural killer and dendritic cell gene transcripts were reduced. PD-L1 inhibition plus 3 × 5 Gy in TRAMP-C1 did not enhance tumour growth delay versus monotherapy. CONCLUSION: 3 × 5 Gy hypofractionated radiotherapy can result in tumour growth delay and immune cell changes in allograft prostate cancer models. Adjuncts beyond immunomodulation may be necessary to improve the radiotherapy-induced anti-tumour response.

Proteomics analysis of the matrisome from MC38 experimental mouse liver metastases.

Dissemination of primary tumors to distant anatomical sites has a substantial negative impact on patient prognosis. The liver is a common site for metastases from colorectal cancer, and patients with hepatic metastases have generally much shorter survival, raising a need to develop and implement novel strategies for targeting metastatic disease. The extracellular matrix (ECM) is a meshwork of highly crosslinked, insoluble high-molecular-mass proteins maintaining tissue integrity and establishing cell-cell interactions. Emerging evidence identifies the importance of the ECM in cancer cell migration, invasion, intravasation, and metastasis. Here, we isolated the ECM from MC38 mouse liver metastases using our optimized method of mild detergent solubilization followed by biochemical enrichment. The matrices were subjected to label-free quantitative mass spectrometry analysis, revealing proteins highly abundant in the metastatic matrisome. The resulting list of proteins upregulated in the ECM significantly predicted survival in patients with colorectal cancer but not other cancers with strong involvement of the ECM component. One of the proteins upregulated in liver metastatic ECM, annexin A1, was not previously studied in the context of cancer-associated matrisome. Here, we show that annexin A1 was markedly upregulated in colon cancer cell lines compared with cancer cells of other origin and also over-represented in human primary colorectal lesions, as well as hepatic metastases, compared with their adjacent healthy tissue counterparts. In conclusion, our study provides a comprehensive ECM characterization of MC38 experimental liver metastases and proposes annexin A1 as a putative target for this disease.NEW & NOTEWORTHY Here, the authors provide an extensive proteomics characterization of murine colorectal cancer liver metastasis matrisome (the ensemble of all extracellular matrix molecules). The findings presented in this study may enable identification of therapeutic targets or biomarkers of hepatic metastases.

Factors predicting ablation site recurrence following percutaneous microwave ablation of colorectal hepatic metastases.

BACKGROUND: Microwave ablation (MWA) is a recognised treatment option for liver metastases. The size of the tumour is a well-established factor that influences the success of MWA. However, the effect of "heat sink" on the success of MWA for hepatic metastases is unclear. The aim of this study was to determine whether heat sink effect is a factor that contributes to ablation site recurrence (ASR). METHODS: A prospectively maintained database of patients who underwent percutaneous MWA for treatment of colorectal liver metastases was analysed. Imaging and demographic characteristics were compared between metastases that recurred following ablation and those that did not. Proximity to a large hepatic vein was defined as <10 mm. RESULTS: 126 ablations in 87 patients met the inclusion criteria and were studied over a median follow-up period of 28 (12-75) months. ASR was detected in 43 ablations (34%) and was associated with clinical risk score (CRS) ≥2 (OR 2.2 95% CI 1.3-3.3, p = 0.029), metastasis size (OR 0.953 95% CI (0.929-0.978), p < 0.001) and proximity to a large hepatic vein (OR 7.5 95%CI 2.4-22.8, p < 0.001). Proximity to a large hepatic vein was not associated with reduced overall survival (OS) but was associated with liver-specific recurrence (HR 4.7 95%CI 1.7-12.5, p = 0.004). CONCLUSIONS: In addition to tumour size proximity to large hepatic venous structures is an independent predictor of ASR and liver-specific recurrence following MWA. However, this was not associated with overall survival.

Radiation combined with macrophage depletion promotes adaptive immunity and potentiates checkpoint blockade.

Emerging evidence suggests a role for radiation in eliciting anti-tumour immunity. We aimed to investigate the role of macrophages in modulating the immune response to radiation. Irradiation to murine tumours generated from colorectal (MC38) and pancreatic (KPC) cell lines induced colony-stimulating factor 1 (CSF-1). Coincident with the elevation in CSF-1, macrophages increased in tumours, peaking 5 days following irradiation. These tumour-associated macrophages (TAMs) were skewed towards an immunosuppressive phenotype. Macrophage depletion via anti-CSF (aCSF) reduced macrophage numbers, yet only achieved tumour growth delay when combined with radiation. The tumour growth delay from aCSF after radiation was abrogated by depletion of CD8 T cells. There was enhanced recognition of tumour cell antigens by T cells isolated from irradiated tumours, consistent with increased antigen priming. The addition of anti-PD-L1 (aPD-L1) resulted in improved tumour suppression and even regression in some tumours. In summary, we show that adaptive immunity induced by radiation is limited by the recruitment of highly immunosuppressive macrophages. Macrophage depletion partly reduced immunosuppression, but additional treatment with anti-PD-L1 was required to achieve tumour regression.

Dynamic matrisome: ECM remodeling factors licensing cancer progression and metastasis.

The main cause of cancer-related mortality, metastasis, is a complex, multi-step process. The extracellular matrix (ECM) component of solid tumors has been implicated in metastatic progression; however, the ECM exists as a complex macromolecular substrate and it is unclear how its molecular composition promotes cancer progression. ECM homeostasis is regulated by various secreted proteins including cross-linkers (e.g., lysyl oxidases and transglutaminases), modifying enzymes (e.g., sulfatases and extracellular kinases), proteases (e.g., matrix metalloproteinases, heparanase, and cathepsins) and protease inhibitors (e.g., tissue inhibitors of metalloproteinases, cystatins, and serpins); each of which can alter the structural, mechanical, and biochemical properties of the ECM. Emerging evidence indicates that altered ECM regulator activity in cancer triggers pathological ECM remodeling facilitating metastatic dissemination making ECM regulators potential targets for cancer therapy. In this review, we summarize and critically discuss the existing literature on the role of ECM regulators in cancer metastasis.

A core matrisome gene signature predicts cancer outcome.

BACKGROUND: Accumulating evidence implicates the tumour stroma as an important determinant of cancer progression but the protein constituents relevant for this effect are unknown. Here we utilised a bioinformatics approach to identify an extracellular matrix (ECM) gene signature overexpressed in multiple cancer types and strongly predictive of adverse outcome. METHODS: Gene expression levels in cancers were determined using Oncomine. Geneset enrichment analysis was performed using the Broad Institute desktop application. Survival analysis was performed using KM plotter. Survival data were generated from publically available genesets. RESULTS: We analysed ECM genes significantly upregulated across a large cohort of patients with ovarian, lung, gastric and colon cancers and defined a signature of nine commonly upregulated genes. Each of these nine genes was considerably overexpressed in all the cancers studied, and cumulatively, their expression was associated with poor prognosis across all data sets. Further, the gene signature expression was associated with enrichment of genes governing processes linked to poor prognosis, such as EMT, angiogenesis, hypoxia, and inflammation. CONCLUSIONS: Here we identify a nine-gene ECM signature, which strongly predicts outcome across multiple cancer types and can be used for prognostication after validation in prospective cancer cohorts.

Acalculous Cholecystitis: Is an Elective Interval Cholecystectomy Necessary.

BACKGROUND: Acute acalculous cholecystitis (AAC) accounts for 5-10% of cases of acute cholecystitis. The advantage of interval cholecystectomy for patients with AAC is unclear. Therefore, a retrospective analysis of patients diagnosed with AAC at our institution was performed over a 5-year period. METHODS: Patients were identified via hospital coding using the keywords "acalculous cholecystitis, cholecystostomy and gall bladder perforation." Follow-up data was obtained by performing a retrospective review of the patients' hospital records. RESULTS: A total of 33 patients with AAC were identified and followed for a median period of 18 months. The median age at presentation was 70 (10-96) and American Society of Anesthesiologists (ASA) grade was 3 (1-5). Twenty-three patients (70%) were treated with antibiotics alone, 7 patients (21%) with percutaneous cholecystostomy and 3 patients (9%) with laparoscopic cholecystectomy. The 90-day mortality rate was 30% with significant correlation to comorbid status, as all deaths occurred in ASA grade 3-5 individuals (p = 0.020). Two patients (6%) developed recurrent AAC and were managed non-operatively. CONCLUSION: Antibiotics and cholecystostomy were the mainstay of AAC management, and comorbid status influenced related mortality. Our results suggest that it appears safe to avoid interval cholecystectomy in patients who recover from AAC, as they are typically high-risk surgical candidates.

Possible congenital dilatation of the pancreatic duct.

The main pancreatic duct can become dilated in a number of conditions. We describe a patient with gross dilatation of the main pancreatic duct without evidence of causative underlying pathology suggesting congenital dilatation of the pancreatic duct. A 36-year-old man presented with signs of intestinal obstruction and a history of surgery for congenital pyloric stenosis. Incidental findings on CT showed a massively dilated main pancreatic duct. On MRI there was no duct irregularity or solid mural nodule, making a main duct intraductal papillary mucinous neoplasm unlikely. Endoscopic ultrasound findings were in keeping with those on MRI. Fine needle aspiration revealed a non-viscous fluid with a low carcinoembryonic antigen and high amylase concentration, consistent with normal pancreatic fluid levels rather than a mucinous collection. After 1 year, the cyst remains unchanged. This patient will be kept under surveillance with yearly MRI.

Neutrophils promote hepatic metastasis growth through fibroblast growth factor 2-dependent angiogenesis in mice.

Hepatic metastases are amenable to ablation; however, many patients are not suitable candidates for such therapy and recurrence is common. The tumor microenvironment is known to be essential for metastatic growth, yet identification of plausible targets for cancer therapy in the microenvironment has proven elusive. We found that human colorectal cancer liver metastases and murine gastrointestinal experimental liver metastases are infiltrated by neutrophils. Plasticity in neutrophils has recently been shown to lead to both protumor and antitumor effects. Here, neutrophils promoted the growth of hepatic metastases, given that depletion of neutrophils in already established, experimental, murine liver metastases led to diminished metastatic growth. Decreased growth was associated with reductions in vascular density and branching suggestive of vessel normalization. Metastasis-associated neutrophils expressed substantially more fibroblast growth factor 2 (FGF2) than naïve neutrophils, indicating neutrophil polarization by the tumor microenvironment. Administration of FGF2 neutralizing antibody to mice bearing experimental liver metastases phenocopied neutrophil depletion by reducing liver metastatic colony growth, vascular density, and branching. CONCLUSION: Here, we show, using FGF2 as an example, that identification of factors responsible for the protumoral effects of infiltrating myeloid cells can be used to target established liver metastases. Such therapies could be utilized to limit disease progression and potentiate the effects of standard ablative therapies. (Hepatology 2017;65:1920-1935).

Targeting the CCL2-CCR2 signaling axis in cancer metastasis.

The CCL2-CCR2 signaling axis has generated increasing interest in recent years due to its association with the progression of cancer. Although first described as a chemotactic molecule with physiological roles in regulating inflammation, recent studies have revealed a pro-tumorigenic function for CCL2 in favoring cancer development and subsequent metastasis. CCL2 binds the cognate receptor CCR2, and together this signaling pair has been shown to have multiple pro-tumorigenic roles, from mediating tumor growth and angiogenesis to recruiting and usurping host stromal cells to support tumor progression. The importance of CCL2-CCR2 signaling has been further championed by the establishment of clinical trials targeting this signaling pair in solid and metastatic cancers. Here we review the roles of CCL2-CCR2 signaling in the development and progression of cancer metastasis. We further evaluate the outcome of several clinical trials targeting either CCL2 or CCR2, and discuss the prospects and challenges of manipulating CCL2-CCR2 interaction as a potential approach for combating metastatic disease.

Systematic Review and Meta-analysis of Current Experience in Treating IPNB: Clinical and Pathological Correlates.

OBJECTIVE: To systematically review studies reporting clinicopathological features of intraductal papillary neoplasm of the bile duct (IPNB) to provide evidence-based guidance for management. BACKGROUND: IPNB is a rare tumor type. Management decisions are currently based upon anecdotal evidence and small case series. To data, there has been no systematic review of IPNB literature. METHODS: MEDLINE, EMBASE, and the Cochrane Database of Systematic Reviews were searched and data were extracted from relevant studies. Meta-analysis was used to pool study estimates. Evidence of association was determined by comparing pooled crude odds ratios (OR) derived from abstracted data. RESULTS: Fifty-seven retrospective case series were included. At least 43% of 476 specimens contained invasive disease. Invasive tumors were found at significantly higher frequency in pancreaticobiliary than intestinal, gastric or oncocytic-type IPNB [pooled OR 2.5, 95% confidence interval (CI) 1.5-4.2, P < 0.001]. A significantly higher proportion of pancreaticobiliary tumors compared with intestinal tumors expressed MUC-1 [86.4% (95% CI 75.1%-94.7%) vs 13.2% (95% CI 4.6%-25.2%), respectively P < 0.001]. IPNB identified in centers from Asia were more likely to be intrahepatic and were less frequently invasive compared with those from Western centers. Pooled estimates of absolute survival after IPNB resection were 96% (95% CI 93%-99%) at 1 year, 79% (95% CI 69%-88%) at 3 years, and 65% (95% CI 46%-76%) at 5 years. CONCLUSIONS: Early surgery is advisable for radiologically suspected IPNB as it is frequently invasive. The pathobiology of IPNB demonstrates geographic variation. Pancreaticobiliary IPNB expresses MUC1 and is more frequently associated with invasive disease than other IPNB subtypes.

Recruitment of myeloid cells to the tumor microenvironment supports liver metastasis.

Tumor-infiltrating immune cells play important roles in metastasis. We have recently revealed the recruitment of a specific myeloid cell subset (CD11b/Gr1mid) to hepatic metastases. Such a recruitment relies on CCL2/CCR2 signaling and acts to sustain metastatic growth. A similar cell subset was identified in patients bearing hepatic metastases of colorectal cancer, highlighting the potential therapeutic relevance of our findings.

Recruitment of a myeloid cell subset (CD11b/Gr1 mid) via CCL2/CCR2 promotes the development of colorectal cancer liver metastasis.

UNLABELLED: Liver metastasis from colorectal cancer is a leading cause of cancer mortality. Myeloid cells play pivotal roles in the metastatic process, but their prometastatic functions in liver metastasis remain incompletely understood. To investigate their role, we simulated liver metastasis in C57BL/6 mice through intrasplenic inoculation of MC38 colon carcinoma cells. Among the heterogeneous myeloid infiltrate, we identified a distinct population of CD11b/Gr1(mid) cells different from other myeloid populations previously associated with liver metastasis. These cells increased in number dramatically during establishment of liver metastases and were recruited from bone marrow by tumor-derived CCL2. Liver metastasis of Lewis lung carcinoma cells followed this pattern but this mechanism is not universal as liver colonization by B16F1 melanoma cells did not recruit similar subsets. Inhibition of CCL2 signaling and absence of its cognate receptor CCR2 reduced CD11b/Gr1(mid) recruitment and decreased tumor burden. Depletion of the CD11b/Gr1(mid) subset in a transgenic CD11b-diphtheria toxin receptor mouse model markedly reduced tumor cell proliferation. There was no evidence for involvement of an adaptive immune response in the prometastatic effects of CD11b/Gr1(mid) cells. Additionally, an analogous myeloid subset was found in liver metastases of some colorectal cancer patients. CONCLUSION: Collectively, our findings highlight the importance of myeloid cells--in this case a selective CD11b/Gr1(mid) subset--in sustaining development of colorectal cancer liver metastasis and identify a potential target for antimetastatic therapy.

Laparoscopic-assisted endoscopic sigmoidopexy: a new surgical option for sigmoid volvulus.

OBJECTIVES: Sigmoid volvulus accounts for 5% of cases of large-bowel obstruction. Here, we present the development of a new minimally invasive treatment method that aims to reduce the complication rate of standard percutaneous endoscopic colostomy tube insertion and negate the need for prolonged anesthesia or colectomy. METHODS: Six patients underwent laparoscopic-assisted endoscopic sigmoidopexy for recurrent sigmoid volvulus at a mean age of 80.5 years (range, 76-83). The volvulus was decompressed endoscopically before laparoscopic adhesiolysis and detorsion of the sigmoid. Finally, the sigmoid was approximated with the anterior abdominal wall, and 2 endoscopically placed percutaneous endoscopic colostomy tubes were inserted. Later, the external component of the percutaneous endoscopic colostomy tubes was removed, and the internal parts were passed by way of the rectum. RESULTS: Each operation was completed successfully in a mean time of 69 minutes and with no intraoperative complication. The mean postoperative stay was 20 days (range, 4-54). At median follow-up of 10.8 months, all patients were tube free with no incidence of recurrent volvulus, inadvertent tube traction, or leak. CONCLUSIONS: This preliminary report shows laparoscopic-assisted endoscopic sigmoidopexy to be a safe treatment modality for recurrent sigmoid volvulus. As such, it is particularly useful for elderly patients, for whom colectomy is a high-risk procedure.