Sequential histologic evolution of gallbladder inflammation in acute cholecystitis over the first 10 days after onset of symptoms.

BACKGROUND: The timing of cholecystectomy during acute cholecystitis (AC) is controversial, especially whether it is advisable to perform in patients with duration of symptoms between 3 and 10 days. The purpose of this study is to define clearly the sequential evolution of histological changes following symptoms onset to guide recommendations regarding timing of cholecystectomy. METHODS: We identified patients with AC (2005-2018) who had cholecystectomy within 10 days of symptom onset of a first attack of AC. Histologic features of gallbladder injury including cellular and exudative inflammatory response to injury were determined on blinded pathologic slides. RESULTS: One hundred and forty-nine patients were divided into three groups; early-who underwent cholecystectomy 1-3 days after symptom-onset, intermediate-4-6 days, and late-7-10 days. Key features of injury were necrosis and hemorrhage. A subgroup of patients in the early phase developed severe necrosis and hemorrhage of an extent associated with difficult cholecystectomy. Large spikes in extent of necrosis and hemorrhage occurred at 7-10 days. Major inflammatory responses to injury were eosinophilic and lymphocytic infiltration and early fibrosis. CONCLUSIONS: Severe necrosis may develop rapidly and be present in the early period after symptom onset of AC. Cholecystectomy may be reasonable in some patients but by day 7-10, severe necrosis and hemorrhage may be expected to be present in most patients.

Primary Mesenchymal Tumors of the Thyroid Gland: A Modern Retrospective Cohort Including the First Case of TFE3-Translocated Malignant Perivascular Epithelioid Cell Tumor (PEComa).

Primary mesenchymal tumors of the thyroid gland are extremely rare, with only case reports and small case series documented in the English literature, many of which were published prior to the era of molecular pathology. In the current study, we aim to present a contemporary multi-centric cohort of thyroid mesenchymal tumors. Nineteen primary thyroid mesenchymal tumors were collected from three tertiary centers. Their clinicopathologic features, immunoprofile, molecular alterations, and outcome were described. Eight cases were classified as benign or intermediate with solitary fibrous tumor being the most common histotype (n = 3). The remaining 11 cases were malignant, including three angiosarcomas, one epithelioid hemangioendothelioma, one adamantinoma-like Ewing sarcoma, one biphasic synovial sarcoma, one malignant melanocytic peripheral nerve sheath tumor (melanotic schwannoma), one myxofibrosarcoma, and two undifferentiated pleomorphic/spindle sarcomas (one of which was radiation-induced). Six tumors showed characteristic diagnostic translocations. We herein also described the first case of thyroid malignant perivascular epithelioid cell tumor (PEComa) with RBM10-TFE3 fusion in a 35-year-old female patient. Thyroid mesenchymal tumors, benign or malignant, are rare with a broad spectrum of possible diagnoses. A comprehensive examination to include histology, immunohistochemistry, and molecular testing is essential for the correct diagnosis and to distinguish them from anaplastic thyroid carcinoma. PEComa may occur as a primary tumor of the thyroid gland, expanding the histologic spectrum of thyroid mesenchymal tumors.

Re-defining a high volume center for pancreaticoduodenectomy.

BACKGROUND: The purpose of this study was to re-evaluate the previously utilized definitions of high volume center for pancreaticoduodenectomy to determine/establish an objective, evidence based threshold of hospital volume associated with improvement in perioperative mortality. METHODS: Patients who underwent pancreaticoduodenectomy were identified using the National Cancer Database from 2004 to 2015. The relationship between hospital volume and 90-day mortality was assessed using a logistic regression model. Receiver Operator Characteristic analysis was performed and Youden's statistic was utilized to calculate the optimal cut offs. RESULTS: 42,402 patients underwent elective Pancreaticoduodenectomy at 1238 unique hospitals. A logistic regression was performed which showed a significant inverse linear association between institutional volume and overall 90 day mortality. The maximum improvement in 90 day mortality is seen if the average annual hospital volume was greater than 9 (OR = 0.647 (0.595-0.702), p < 0.0001). When analysis is limited to hospitals that performed >9 cases per year, the maximum improvement in 90 day mortality was noticed at 36 cases per year (OR = 0.458 (0.399-0.525), p < 0.0001). CONCLUSIONS: Based on our results, we recommend defining low, medium, and high volume centers for pancreaticoduodenectomy as hospitals with average annual volume less than 9, 9 to 35, and more than 35 cases per year, respectively.

Adjuvant therapy following resection of gastroenteropancreatic neuroendocrine tumors provides no recurrence or survival benefit.

BACKGROUND AND OBJECTIVES: Lack of high-level evidence supporting adjuvant therapy for patients with resected gastroenteropancreatic neuroendocrine tumors (GEP NETs) warrants an evaluation of its non-standard of care use. METHODS: Patients with primary GEP NETs who underwent curative-intent resection at eight institutions between 2000 and 2016 were identified; 91 patients received adjuvant therapy. Recurrence-free survival (RFS) and overall survival (OS) were compared between adjuvant cytotoxic chemotherapy and somatostatin analog cohorts. RESULTS: In resected patients, 33 received cytotoxic chemotherapy, and 58 received somatostatin analogs. Five-year RFS/OS was 49% and 83%, respectively. Cytotoxic chemotherapy RFS/OS was 36% and 61%, respectively, lower than the no therapy cohort (P < .01). RFS with somatostatin analog therapy (compared to none) was lower (P < .01), as was OS (P = .01). On multivariable analysis, adjuvant cytotoxic therapy was negatively associated with RFS but not OS controlling for patient/tumor-specific characteristics (RFS P < .01). CONCLUSIONS: Our data, reflecting the largest reported experience to date, demonstrate that adjuvant therapy for resected GEP NETs is negatively associated with RFS and confers no OS benefit. Selection bias enriching our treatment cohort for individuals with unmeasured high-risk characteristics likely explains some of these results; future studies should focus on patient subsets who may benefit from adjuvant therapy.

Purity Independent Subtyping of Tumors (PurIST), A Clinically Robust, Single-sample Classifier for Tumor Subtyping in Pancreatic Cancer.

PURPOSE: Molecular subtyping for pancreatic cancer has made substantial progress in recent years, facilitating the optimization of existing therapeutic approaches to improve clinical outcomes in pancreatic cancer. With advances in treatment combinations and choices, it is becoming increasingly important to determine ways to place patients on the best therapies upfront. Although various molecular subtyping systems for pancreatic cancer have been proposed, consensus regarding proposed subtypes, as well as their relative clinical utility, remains largely unknown and presents a natural barrier to wider clinical adoption. EXPERIMENTAL DESIGN: We assess three major subtype classification schemas in the context of results from two clinical trials and by meta-analysis of publicly available expression data to assess statistical criteria of subtype robustness and overall clinical relevance. We then developed a single-sample classifier (SSC) using penalized logistic regression based on the most robust and replicable schema. RESULTS: We demonstrate that a tumor-intrinsic two-subtype schema is most robust, replicable, and clinically relevant. We developed Purity Independent Subtyping of Tumors (PurIST), a SSC with robust and highly replicable performance on a wide range of platforms and sample types. We show that PurIST subtypes have meaningful associations with patient prognosis and have significant implications for treatment response to FOLIFIRNOX. CONCLUSIONS: The flexibility and utility of PurIST on low-input samples such as tumor biopsies allows it to be used at the time of diagnosis to facilitate the choice of effective therapies for patients with pancreatic ductal adenocarcinoma and should be considered in the context of future clinical trials.

Association of preoperative monocyte-to-lymphocyte and neutrophil-to-lymphocyte ratio with recurrence-free and overall survival after resection of pancreatic neuroendocrine tumors (US-NETSG).

BACKGROUND: Preoperative systemic inflammatory response plays a crucial role in tumorigenesis, progression, and prognosis; and neutrophil, monocyte, and lymphocyte counts serve as important biomarkers. An altered monocyte-to-lymphocyte ratio (MLR) and neutrophil-to-lymphocyte ratio (NLR) has been reported to be associated with a favorable prognosis for certain hematologic malignancies and breast cancer. The aim of this study was to investigate the prognostic significance of MLR, NLR in patients with resectable PNETs. METHODS: Patients undergoing surgery for PNETs between 2000 and 2016 were identified using a large, multi-center database. NLR and MLR were calculated and Contal and O'Quigley analysis was used to determine the optimal cutoff value. RESULTS: A total of 620 patients were included in the analytic cohort. The prognostic implications of blood count parameters were evaluated in both univariate and multivariate analysis. The univariate analysis revealed that low MLR and NLR is associated with significantly improved overall survival (OS; P < .01) and recurrence-free survival (RFS; P < .01). On multivariate analysis, in addition to tumor size and grade, NLR was an independent predictor of improved OS and RFS. CONCLUSION: In addition to established tumor-specific factors, preoperative NLR levels can serve as a valuable biomarker that can be used as a predictor of OS and RFS after resection of PNETs.

Agonism of CD11b reprograms innate immunity to sensitize pancreatic cancer to immunotherapies.

Although checkpoint immunotherapies have revolutionized the treatment of cancer, not all tumor types have seen substantial benefit. Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy in which very limited responses to immunotherapy have been observed. Extensive immunosuppressive myeloid cell infiltration in PDAC tissues has been postulated as a major mechanism of resistance to immunotherapy. Strategies concomitantly targeting monocyte or granulocyte trafficking or macrophage survival, in combination with checkpoint immunotherapies, have shown promise in preclinical studies, and these studies have transitioned into ongoing clinical trials for the treatment of pancreatic and other cancer types. However, compensatory actions by untargeted monocytes, granulocytes, and/or tissue resident macrophages may limit the therapeutic efficacy of such strategies. CD11b/CD18 is an integrin molecule that is highly expressed on the cell surface of these myeloid cell subsets and plays an important role in their trafficking and cellular functions in inflamed tissues. Here, we demonstrate that the partial activation of CD11b by a small-molecule agonist (ADH-503) leads to the repolarization of tumor-associated macrophages, reduction in the number of tumor-infiltrating immunosuppressive myeloid cells, and enhanced dendritic cell responses. These actions, in turn, improve antitumor T cell immunity and render checkpoint inhibitors effective in previously unresponsive PDAC models. These data demonstrate that molecular agonism of CD11b reprograms immunosuppressive myeloid cell responses and potentially bypasses the limitations of current clinical strategies to overcome resistance to immunotherapy.

National Pancreatic Fistula Rates after Minimally Invasive Pancreaticoduodenectomy: A NSQIP Analysis.

BACKGROUND: There is a substantial learning curve associated with minimally invasive pancreaticoduodenectomy (MIPD). We sought to determine if national MIPD pancreatic fistula rates are decreasing with time. STUDY DESIGN: All patients undergoing elective MIPD and accrued into the pancreatectomy-targeted NSQIP database between 2014 and 2017 were included in the study. Trends in MIPD outcomes by year were examined using Cochran-Armitage and Mann-Kendall tests for trend. Multivariable logistic regression was used to assess for an independent association between increasing year of operation and pancreatic fistula. RESULTS: There were 1,096 patients who underwent MIPD between 2014 and 2017. There was a significant trend toward decreasing pancreatic fistula rates (23.6% vs 19.2% vs 14.9% vs 12.7%, p < 0.01) and clinically relevant pancreatic fistula rates (18.3% vs 15.4% vs 11.1% vs 9.1%, p < 0.01) by increasing year. In multivariable analysis, increasing year of operation was independently protective against pancreatic fistula (odds ratio [OR] 0.76 per year, p < 0.01) and clinically relevant pancreatic fistula (OR 0.73 per year, p < 0.01). Patients without pancreas ducts < 3 mm or soft pancreas gland texture experienced a significant decreasing trend in pancreatic fistula rates (23.7% vs 13.2% vs 10.3% vs 8.0%, p < 0.01) and clinically relevant pancreatic fistula rates (18.3% vs 9.1% vs 5.2% vs 6.0%, p < 0.01), respectively, by increasing year. However, there was not a significant trend in pancreatic fistula rate or clinically relevant fistula rate among patients having either pancreas ducts < 3 mm or soft gland texture. CONCLUSIONS: National MIPD pancreatic fistula rates are improving with time. A major contributing factor for this finding is better outcomes in patients who are at lower risk of pancreatic fistula, which could be a reflection of evolving minimally invasive anastomotic techniques.

Predictive Value of Chromogranin A and a Pre-Operative Risk Score to Predict Recurrence After Resection of Pancreatic Neuroendocrine Tumors.

INTRO: Chromogranin A (CgA) may be prognostic for patients with neuroendocrine tumors; however, the clinical utility of this test is unclear. METHODS: Patients undergoing resection for pancreatic neuroendocrine tumors (pNET) were selected from the eight institutions of the US Neuroendocrine Tumor Study Group database. Cox regression was used to identify pre-operative variables that predicted recurrence-free survival (RFS), and those with p < 0.1 were included in a risk score. The risk score was tested in a unique subset of the overall cohort. RESULTS: In the entire cohort of 287 patients, median follow-up time was 37 months, and 5-year RFS was 73%. Cox regression analysis identified four variables for inclusion in the risk score: CgA > 5x ULN (HR 4.3, p = 0.01), tumor grade 2/3 (HR 3.7, p = 0.01), resection for recurrent disease (HR 6.2, p < 0.01), and tumor size > 4 cm (HR 4.5, p = 0.1). Each variable was assigned 1 point. Risk-score testing in the unique validation cohort of 63 patients revealed a 95% negative predictive value for recurrence in patients with zero points. DISCUSSION: This simple pre-operative risk scoring system resulted in a high degree of specificity for identifying patients at low-risk for tumor recurrence. This test can be utilized pre-operatively to aid informed decision-making.

Social Belonging as a Predictor of Surgical Resident Well-being and Attrition.

OBJECTIVE: In light of the predicted shortage of surgeons, attrition from surgical residency is a significant problem. Prior data have shown that those who are happier are more productive, and those who are less well have higher rates of absenteeism. This study sought to identify the role of social belonging and its relationship to well-being and risk of attrition. DESIGN: Surgical residents were invited to participate in an online survey containing measures of social belonging (a 10-item scale adapted from previous studies), well-being (the Dupuy Psychological General Well-Being Scale, Beck Depression Inventory Short Form, and Maslach Burnout Inventory), and risk of attrition (indicated by frequency of thoughts of leaving the program). SETTING: We surveyed residents at 2 tertiary care centers, Stanford Health Care (2010, 2011, and 2015) and Washington University in St. Louis (2017). PARTICIPANTS: Categorical general surgery residents, designated preliminary residents going into 7 surgical subspecialties, and nondesignated preliminary residents were included. RESULTS: One hundred sixty-nine residents responded to the survey for a response rate of 66%. Belonging was positively correlated with general psychological well-being (r = 0.56, p < 0.0001) and negatively correlated with depression (r = -0.57, p < 0.0001), emotional exhaustion (r = -0.58, p < 0.0001), and depersonalization (r = -0.36, p < 0.0001). Further, belonging was negatively correlated with frequency of thoughts of leaving residency (r = -0.45, p < 0.0001). In regression analysis controlling for demographic variables, belonging was a significant positive predictor of psychological well-being (B = 0.95, t = 8.18, p < 0.0001) and a significant negative predictor of thoughts of leaving (B = -1.04, t = -5.44, p < 0.0001). CONCLUSIONS: Social belonging has a significant positive correlation with well-being and negative correlation with thoughts of leaving surgical training. Lack of social belonging appears to be a significant predictor of risk of attrition in surgical residency. Efforts to enhance social belonging may protect against resident attrition.

Residual Tumor Index: A Prognostically Significant Pathologic Parameter in Neoadjuvant-treated Pancreatic Ductal Adenocarcinoma.

In the setting of neoadjuvant therapy (NAT) for pancreatic ductual adenocarcinoma (PDAC), accurate measurement of tumor size, and consequently, staging based on AJCC eighth edition, is difficult. Attempts to address the limitations of tumor size in the NAT setting have included correlation of residual tumor percent with survival. However, only cases with complete pathologic response or minimal residual disease have shown better prognosis compared with all other groups. To date, no studies have simultaneously evaluated the prognostic value of tumor size and tumor regression in the setting of PDAC status post NAT (NAT-PDAC). Our aim was to study the prognostic value of residual tumor index (RTI), a metric combining residual tumor percent and tumor bed size as an interaction term (% residual tumor×tumor bed size [cm]). In a cohort of 105 cases of NAT-PDAC, we show that RTI supersedes the prognostic value of AJCC eighth edition T staging via multivariate cox regression. At a binary cutoff of 0.35 for RTI, the hazard ratio for recurrence-free survival is 3.26 (95% confidence interval, 1.51-7.04), P<0.01. We further identified cutoffs of ≤0.2, 0.2 to 2 and >2 that stratified our cases into 3 groups via RTI, which were statistically significant in Kaplan-Meier curve analysis of recurrence-free survival (P<0.01) and overall survival (P<0.01). RTI represents a novel metric for combining the prognostic value of tumor size and residual tumor in NAT-PDAC.

Recruitment of CCR2+ tumor associated macrophage to sites of liver metastasis confers a poor prognosis in human colorectal cancer.

The tumor microenvironment (TME) represents a significant barrier to creating effective therapies for metastatic colorectal cancer (mCRC). In several malignancies, bone marrow derived CCR2+ inflammatory monocytes (IM) are recruited to the TME by neoplastic cells, where they become immunosuppressive tumor associated macrophages (TAM). Here we report that mCRC expression of the chemokine CCL2 facilitates recruitment of CCR2+ IM from the bone marrow to the peripheral blood. Immune monitoring of circulating monocytes in patients with mCRC found this influx was a prognostic biomarker and correlated with worse clinical outcomes. At the metastatic site, mCRC liver tumors were heavily infiltrated by TAM, which displayed a robust ability to dampen endogenous anti-tumor lymphocyte activity. Using a murine model of mCRC that recapitulates these findings from human disease, we show that targeting CCR2 reduces TAM accumulation in liver metastasis and restores anti-tumor immunity. Additional quantitative analysis of hepatic metastatic tumor burden and treatment efficacy found that administration of a small molecule CCR2 inhibitor (CCR2i) improves chemotherapeutic responses and increases overall survival in mice with mCRC liver tumors. Our study suggests that targeting the CCL2/CCR2 chemokine axis decreases TAM at the metastatic site, disrupting the immunosuppressive TME and rendering mCRC susceptible to anti-tumor T-cell responses.

Breast and pancreatic cancer interrupt IRF8-dependent dendritic cell development to overcome immune surveillance.

Tumors employ multiple mechanisms to evade immune surveillance. One mechanism is tumor-induced myelopoiesis, whereby the expansion of immunosuppressive myeloid cells can impair tumor immunity. As myeloid cells and conventional dendritic cells (cDCs) are derived from the same progenitors, we postulated that myelopoiesis might impact cDC development. The cDC subset, cDC1, which includes human CD141+ DCs and mouse CD103+ DCs, supports anti-tumor immunity by stimulating CD8+ T-cell responses. Here, to understand how cDC1 development changes during tumor progression, we investigated cDC bone marrow progenitors. We found localized breast and pancreatic cancers induce systemic decreases in cDC1s and their progenitors. Mechanistically, tumor-produced granulocyte-stimulating factor downregulates interferon regulatory factor-8 in cDC progenitors, and thus results in reduced cDC1 development. Tumor-induced reductions in cDC1 development impair anti-tumor CD8+ T-cell responses and correlate with poor patient outcomes. These data suggest immune surveillance can be impaired by tumor-induced alterations in cDC development.

Intestinal resection-associated metabolic syndrome.

BACKGROUND: Short bowel syndrome occurs following massive small bowel resection (SBR) and is one of the most lethal diseases of childhood. We have previously demonstrated hepatic steatosis, altered gut microbiome, and increased fat deposition in our murine model of SBR. These novel findings prompted us to investigate potential alterations in glucose metabolism and systemic inflammation following intestinal resection. METHODS: Male C57BL6 mice underwent 50% proximal SBR or sham operation. Body weight and composition were measured. Fasting blood glucose (FBG), glucose, and insulin tolerance testing were performed. Small bowel, pancreas, and serum were collected at sacrifice and analyzed. RESULTS: SBR mice gained less weight than shams after 10weeks. Despite this, FBG in resected mice was significantly higher than sham animals. After SBR, mice demonstrated perturbed body composition, higher blood glucose, increased pancreatic islet area, and increased systemic inflammation compared with sham mice. Despite these changes, we found no alteration in insulin tolerance after resection. CONCLUSIONS: After massive SBR, we present evidence for abnormal body composition, glucose metabolism, and systemic inflammation. These findings, coupled with resection-associated hepatic steatosis, suggest that massive SBR (independent of parenteral nutrition) results in metabolic consequences not previously described and provides further evidence to support the presence of a novel resection-associated metabolic syndrome.

Comparative effectiveness of upfront esophagectomy versus induction chemoradiation in clinical stage T2N0 esophageal cancer: A decision analysis.

OBJECTIVES: We compared the effectiveness of upfront esophagectomy versus induction chemoradiation followed by esophagectomy for overall survival in patients with clinical T2N0 (cT2N0) esophageal cancer. We also assessed the influence of the diagnostic uncertainty of endoscopic ultrasound on the expected benefit of chemoradiation. METHODS: We created a decision analysis model representing 2 treatment strategies for cT2N0 esophageal cancer: upfront esophagectomy that may be followed by adjuvant therapy for upstaged patients and induction chemoradiation for all patients with cT2N0 esophageal cancer followed by esophagectomy. Parameter values within the model were obtained from published data, and median survival for pathologic subgroups was derived from the National Cancer Database. In sensitivity analyses, staging uncertainty of endoscopic ultrasound was introduced by varying the probability of pathologic upstaging. RESULTS: The baseline model showed comparable median survival for both strategies: 48.3 months for upfront esophagectomy versus 45.9 months for induction chemoradiation and surgery. The sensitivity analysis demonstrated induction chemoradiation was beneficial, with probability of upstaging > 48.1%, which is within the published range of 32% to 65% probability of pathologic upstaging after cT2N0 diagnosis. The presence of any of 3 key variables (size larger than 3 cm, high grade, or lymphovascular invasion) was associated with > 48.1% risk of upstaging, thus conferring a survival advantage to induction chemoradiation. CONCLUSIONS: The optimal treatment strategy for cT2N0 esophageal cancer depends on the accuracy of endoscopic ultrasound staging. High-risk features that confer increased probability of upstaging can inform clinical decision making to recommend induction chemoradiation for select cT2N0 patients.

Preoperative predictors of conversion as indicators of local inflammation in acute cholecystitis: strategies for future studies to develop quantitative predictors.

BACKGROUND: Observational studies have identified risk factors for conversion from laparoscopic to open cholecystectomy in acute cholecystitis. The aim of this study is to evaluate the reliability of these predictors and to identify sources of heterogeneity in the studies. METHODS: OVID was searched for papers published from 1995 to 2016. Studies with more than 100 patients were included. Risk factors for conversion were abstracted and categorized by statistical significance. RESULTS: Eleven studies were evaluated. Inflammation with difficulty in anatomic identification was the most common reason of conversion. Because of heterogeneity among studies a quantitative approach was not possible. Therefore, qualitative analysis using a heat map was performed along with investigation into sources of heterogeneity with the aim of creating a framework for future quantitative studies. Age, maleness, and white blood cell count were most commonly identified predictors of conversion. Sources of heterogeneity were criteria for diagnosis of acute cholecystitis, selection of patients for laparoscopic cholecystectomy, selection of variables and variations in their thresholds. CONCLUSIONS: In acute cholecystitis, inflammation is the most common reason for conversion. Age, maleness and white blood cell count are common predictors of conversion. Large scale prospective studies with minimal heterogeneity are needed to establish validity of these and other predictors.

Targeting both tumour-associated CXCR2+ neutrophils and CCR2+ macrophages disrupts myeloid recruitment and improves chemotherapeutic responses in pancreatic ductal adenocarcinoma.

OBJECTIVE: Chemokine pathways are co-opted by pancreatic adenocarcinoma (PDAC) to facilitate myeloid cell recruitment from the bone marrow to establish an immunosuppressive tumour microenvironment (TME). Targeting tumour-associated CXCR2+neutrophils (TAN) or tumour-associated CCR2+ macrophages (TAM) alone improves antitumour immunity in preclinical models. However, a compensatory influx of an alternative myeloid subset may result in a persistent immunosuppressive TME and promote therapeutic resistance. Here, we show CCR2 and CXCR2 combined blockade reduces total tumour-infiltrating myeloids, promoting a more robust antitumour immune response in PDAC compared with either strategy alone. METHODS: Blood, bone marrow and tumours were analysed from PDAC patients and controls. Treatment response and correlative studies were performed in mice with established orthotopic PDAC tumours treated with a small molecule CCR2 inhibitor (CCR2i) and CXCR2 inhibitor (CXCR2i), alone and in combination with chemotherapy. RESULTS: A systemic increase in CXCR2+ TAN correlates with poor prognosis in PDAC, and patients receiving CCR2i showed increased tumour-infiltrating CXCR2+ TAN following treatment. In an orthotopic PDAC model, CXCR2 blockade prevented neutrophil mobilisation from the circulation and augmented chemotherapeutic efficacy. However, depletion of either CXCR2+ TAN or CCR2+ TAM resulted in a compensatory response of the alternative myeloid subset, recapitulating human disease. This was overcome by combined CCR2i and CXCR2i, which augmented antitumour immunity and improved response to FOLFIRINOX chemotherapy. CONCLUSION: Dual targeting of CCR2+ TAM and CXCR2+ TAN improves antitumour immunity and chemotherapeutic response in PDAC compared with either strategy alone.

Targeting tumour-associated macrophages with CCR2 inhibition in combination with FOLFIRINOX in patients with borderline resectable and locally advanced pancreatic cancer: a single-centre, open-label, dose-finding, non-randomised, phase 1b trial.

BACKGROUND: In pancreatic ductal adenocarcinoma, the CCL2-CCR2 chemokine axis is used to recruit tumour-associated macrophages for construction of an immunosuppressive tumour microenvironment. This pathway has prognostic implications in pancreatic cancer, and blockade of CCR2 restores anti-tumour immunity in preclinical models. We aimed to establish the safety, tolerability, and recommended phase 2 oral dose of the CCR2 inhibitor PF-04136309 in combination with FOLFIRINOX chemotherapy (oxaliplatin and irinotecan plus leucovorin and fluorouracil). METHODS: We did this open-label, dose-finding, non-randomised, phase 1b study at one centre in the USA. We enrolled treatment-naive patients aged 18 years or older with borderline resectable or locally advanced biopsy-proven pancreatic ductal adenocarcinoma, an Eastern Cooperative Oncology Group performance status of 1 or less, measurable disease as defined by Response Evaluation Criteria in Solid Tumors version 1.1, and normal end-organ function. Patients were allocated to receive either FOLFIRINOX alone (oxaliplatin 85 mg/m(2), irinotecan 180 mg/m(2), leucovorin 400 mg/m(2), and bolus fluorouracil 400 mg/m(2), followed by 2400 mg/m(2) 46-h continuous infusion), administered every 2 weeks for a total of six treatment cycles, or in combination with oral PF-04136309, administered at a starting dose of 500 mg twice daily in a standard 3 + 3 dose de-escalation design. Both FOLFIRINOX and PF-04136309 were simultaneously initiated with a total treatment duration of 12 weeks. The primary endpoints were the safety, tolerability, and recommended phase 2 dose of PF-04136309 plus FOLFIRINOX, with an expansion phase planned at the recommended dose. We analysed the primary outcome by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT01413022. RESULTS: Between April 19, 2012, and Nov 12, 2014, we treated 47 patients with FOLFIRINOX alone (n=8) or with FOLFIRINOX plus PF-04136309 (n=39). One patient had a dose-limiting toxic effect in the dose de-escalation group receiving FOLFIRINOX plus PF-04136309 at 500 mg twice daily (n=6); this dose was established as the recommended phase 2 dose. We pooled patients in the expansion-phase group (n=33) with those in the dose de-escalation group that received PF-04136309 at the recommended phase 2 dose for assessment of treatment-related toxicity. Six (75%) of the eight patients receiving FOLFIRINOX alone were assessed for treatment toxicity, after exclusion of two (25%) patients due to insurance coverage issues. The median duration of follow-up for treatment toxicity was 72·0 days (IQR 49·5-89·0) in the FOLFIRINOX alone group and 77·0 days (70·0-90·5) in the FOLFIRINOX plus PF-04136309 group. No treatment-related deaths occurred. Two (5%) patients in the FOLFIRINOX plus PF-04136309 group stopped treatment earlier than planned due to treatment-related toxic effects. Grade 3 or higher adverse events reported in at least 10% of the patients receiving PF-04136309 included neutropenia (n=27), febrile neutropenia (n=7), lymphopenia (n=4), diarrhoea (n=6), and hypokalaemia (n=7). Grade 3 or higher adverse events reported in at least 10% of patients receiving FOLFIRINOX alone were neutropenia (n=6), febrile neutropenia (n=1), anaemia (n=2), lymphopenia (n=1), diarrhoea (n=2), hypoalbuminaemia (n=1), and hypokalaemia (n=3). Therapy was terminated because of treatment-related toxicity in one (17%) of the six patients receiving FOLFIRINOX alone. 16 (49%) of 33 patients receiving FOLFIRINOX plus PF-04136309 who had undergone repeat imaging achieved an objective tumour response, with local tumour control achieved in 32 (97%) patients. In the FOLFIRINOX alone group, none of the five patients with repeat imaging achieved an objective response, although four (80%) of those patients achieved stable disease. INTERPRETATION: CCR2-targeted therapy with PF-04136309 in combination with FOLFIRINOX is safe and tolerable. FUNDING: Washington University-Pfizer Biomedical Collaborative.

Standardizing a control group for comparing open with laparoscopic major liver resection in observational studies: reducing the need for correction of clinical heterogeneity.

BACKGROUND: The results of comparative observational trials of liver resections can be problematic because of the large number of covariates that need to be balanced by complex statistical methods. Our purpose was to examine a cohort of patients whose outcomes were specifically representative of a major open hepatectomy, therefore reducing the number of covariates requiring statistical correction in future comparative observational trials. STUDY DESIGN: The cohort was restricted to a single major common liver resection­open right hepatectomy. Subsequent restrictions eliminated covariates whose effects were not due to the liver resection, such as concomitant procedures. Variability was further reduced by including only NSQIP-based data for complications. The Modified Accordion Severity Grading System was used to quantify the complications. RESULTS: Of 114 patients in the NSQIP database, 70 met eligibility criteria. The mean operative time was 243 minutes and 19% of patients were transfused. The most common diagnosis was colorectal metastases, and the R0 resection rate in this group was 94%. One patient (1.4%) died postoperatively, and 25% of patients developed complications. Organ space infection, unplanned intubation, and on ventilator more than 48 hours had the highest fractional burden of complications. The Postoperative Morbidity Index was 0.089. Mean length of stay was 7.7 days. CONCLUSIONS: This study displays results for a cohort of patients who are specifically reflective of a major open liver resection. Use of NSQIP data allows rigorous collection of complication data in a quantifiable manner. This methodology should facilitate comparative observational trials using laparoscopic techniques by reducing the need for statistical correction of unbalanced covariates.

Tumor-induced STAT3 activation in monocytic myeloid-derived suppressor cells enhances stemness and mesenchymal properties in human pancreatic cancer.

Pancreatic cancer (PC) mobilizes myeloid cells from the bone marrow to the tumor where they promote tumor growth and proliferation. Cancer stem cells (CSCs) are a population of tumor cells that are responsible for tumor initiation. Aldehyde dehydrogenase-1 activity in PC identifies CSCs, and its activity has been correlated with poor overall prognosis in human PC. Myeloid cells have been shown to impact tumor stemness, but the impact of immunosuppressive tumor-infiltrating granulocytic and monocytic myeloid-derived suppressor cells (Mo-MDSC) on ALDH1(Bright) CSCs and epithelial to mesenchymal transition is not well understood. In this study, we demonstrate that Mo-MDSC (CD11b(+)/Gr1(+)/Ly6G(-)/Ly6C(hi)) significantly increase the frequency of ALDH1(Bright) CSCs in a mouse model of PC. Additionally, there was significant upregulation of genes associated with epithelial to mesenchymal transition. We also found that human PC converts CD14(+) peripheral blood monocytes into Mo-MDSC (CD14(+)/HLA-DR(low/-)) in vitro, and this transformation is dependent on the activation of the STAT3 pathway. In turn, these Mo-MDSC increase the frequency of ALDH1(Bright) CSCs and promote mesenchymal features of tumor cells. Finally, blockade of STAT3 activation reversed the increase in ALDH1(Bright) CSCs. These data suggest that the PC tumor microenvironment transforms monocytes to Mo-MDSC by STAT3 activation, and these cells increase the frequency of ALDH1(Bright) CSCs. Therefore, targeting STAT3 activation may be an effective therapeutic strategy in targeting CSCs in PC.