Microenvironment drives cell state, plasticity, and drug response in pancreatic cancer.

Prognostically relevant RNA expression states exist in pancreatic ductal adenocarcinoma (PDAC), but our understanding of their drivers, stability, and relationship to therapeutic response is limited. To examine these attributes systematically, we profiled metastatic biopsies and matched organoid models at single-cell resolution. In vivo, we identify a new intermediate PDAC transcriptional cell state and uncover distinct site- and state-specific tumor microenvironments (TMEs). Benchmarking models against this reference map, we reveal strong culture-specific biases in cancer cell transcriptional state representation driven by altered TME signals. We restore expression state heterogeneity by adding back in vivo-relevant factors and show plasticity in culture models. Further, we prove that non-genetic modulation of cell state can strongly influence drug responses, uncovering state-specific vulnerabilities. This work provides a broadly applicable framework for aligning cell states across in vivo and ex vivo settings, identifying drivers of transcriptional plasticity and manipulating cell state to target associated vulnerabilities.

Spatially organized multicellular immune hubs in human colorectal cancer.

Immune responses to cancer are highly variable, with mismatch repair-deficient (MMRd) tumors exhibiting more anti-tumor immunity than mismatch repair-proficient (MMRp) tumors. To understand the rules governing these varied responses, we transcriptionally profiled 371,223 cells from colorectal tumors and adjacent normal tissues of 28 MMRp and 34 MMRd individuals. Analysis of 88 cell subsets and their 204 associated gene expression programs revealed extensive transcriptional and spatial remodeling across tumors. To discover hubs of interacting malignant and immune cells, we identified expression programs in different cell types that co-varied across tumors from affected individuals and used spatial profiling to localize coordinated programs. We discovered a myeloid cell-attracting hub at the tumor-luminal interface associated with tissue damage and an MMRd-enriched immune hub within the tumor, with activated T cells together with malignant and myeloid cells expressing T cell-attracting chemokines. By identifying interacting cellular programs, we reveal the logic underlying spatially organized immune-malignant cell networks.

Protein biomarkers and alternatively methylated cell-free DNA detect early stage pancreatic cancer.

OBJECTIVE: Pancreatic ductal adenocarcinoma (PDAC) is commonly diagnosed at an advanced stage. Liquid biopsy approaches may facilitate detection of early stage PDAC when curative treatments can be employed. DESIGN: To assess circulating marker discrimination in training, testing and validation patient cohorts (total n=426 patients), plasma markers were measured among PDAC cases and patients with chronic pancreatitis, colorectal cancer (CRC), and healthy controls. Using CA19-9 as an anchor marker, measurements were made of two protein markers (TIMP1, LRG1) and cell-free DNA (cfDNA) pancreas-specific methylation at 9 loci encompassing 61 CpG sites. RESULTS: Comparative methylome analysis identified nine loci that were differentially methylated in exocrine pancreas DNA. In the training set (n=124 patients), cfDNA methylation markers distinguished PDAC from healthy and CRC controls. In the testing set of 86 early stage PDAC and 86 matched healthy controls, CA19-9 had an area under the receiver operating characteristic curve (AUC) of 0.88 (95% CI 0.83 to 0.94), which was increased by adding TIMP1 (AUC 0.92; 95% CI 0.88 to 0.96; p=0.06), LRG1 (AUC 0.92; 95% CI 0.88 to 0.96; p=0.02) or exocrine pancreas-specific cfDNA methylation markers at nine loci (AUC 0.92; 95% CI 0.88 to 0.96; p=0.02). In the validation set of 40 early stage PDAC and 40 matched healthy controls, a combined panel including CA19-9, TIMP1 and a 9-loci cfDNA methylation panel had greater discrimination (AUC 0.86, 95% CI 0.77 to 0.95) than CA19-9 alone (AUC 0.82; 95% CI 0.72 to 0.92). CONCLUSION: A combined panel of circulating markers including proteins and methylated cfDNA increased discrimination compared with CA19-9 alone for early stage PDAC.

Anatomic Laparoscopic Partial Hepatectomy of a Segment 4a B-Catenin Mutated Adenoma.

BACKGROUND: Although a ß-catenin mutated hepatocellular adenoma (HCA) is a benign liver tumor, it can cause bleeding, obstruction, pain, and hepatocellular carcinoma.1-3 Because surgery needs to balance these risks with its morbidity, a minimally invasive approach may be well suited.4-6 In this report, a strategic approach to minimally invasive resection of HCA encompassing segment 4a (S4a) is reviewed. PATIENT: A 22-year-old woman with abdominal pain was found to have two liver lesions involving segment 4a (5 cm) and segment 8 (S8) (4.5 cm). Liver biopsy confirmed a ß-catenin mutated HCA in the S4a lesion. After embolization, an anatomic S4a segmentectomy and a partial S8 resection were planned. TECHNIQUE: Three-dimensional modeling was used to perform a preoperative virtual hepatectomy; to visualize the spatial relationship between the HCA, the portal bifurcation, and the hepatic veins; and to preplan the port sites.7 With the patient in the French position, after port placement, intraoperative ultrasound was performed to identify the transection plane.8 The main left portal pedicle and Rex's recessus were exposed, and the branches of S4a were dissected out, clipped, and divided. Using ultrasound, the middle hepatic vein was exposed to define the lateral border of the dissection plane. CONCLUSION: Although a ß-catenin mutated HCA in S4a does not necessitate a formal segmentectomy, understanding the anatomic structures outlining its borders can facilitate the resection, especially for a large HCA. Virtual hepatectomy helps to achieve a detailed comprehension of the complex borders of segment 4a. Preoperative embolization can firm up the tumor and minimize the risk of intraoperative rupture from manipulation.

Lead-Time Trajectory of CA19-9 as an Anchor Marker for Pancreatic Cancer Early Detection.

BACKGROUND & AIMS: There is substantial interest in liquid biopsy approaches for cancer early detection among subjects at risk, using multi-marker panels. CA19-9 is an established circulating biomarker for pancreatic cancer; however, its relevance for pancreatic cancer early detection or for monitoring subjects at risk has not been established. METHODS: CA19-9 levels were assessed in blinded sera from 175 subjects collected up to 5 years before diagnosis of pancreatic cancer and from 875 matched controls from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. For comparison of performance, CA19-9 was assayed in blinded independent sets of samples collected at diagnosis from 129 subjects with resectable pancreatic cancer and 275 controls (100 healthy subjects; 50 with chronic pancreatitis; and 125 with noncancerous pancreatic cysts). The complementary value of 2 additional protein markers, TIMP1 and LRG1, was determined. RESULTS: In the PLCO cohort, levels of CA19-9 increased exponentially starting at 2 years before diagnosis with sensitivities reaching 60% at 99% specificity within 0 to 6 months before diagnosis for all cases and 50% at 99% specificity for cases diagnosed with early-stage disease. Performance was comparable for distinguishing newly diagnosed cases with resectable pancreatic cancer from healthy controls (64% sensitivity at 99% specificity). Comparison of resectable pancreatic cancer cases to subjects with chronic pancreatitis yielded 46% sensitivity at 99% specificity and for subjects with noncancerous cysts, 30% sensitivity at 99% specificity. For prediagnostic cases below cutoff value for CA19-9, the combination with LRG1 and TIMP1 yielded an increment of 13.2% in sensitivity at 99% specificity (P = .031) in identifying cases diagnosed within 1 year of blood collection. CONCLUSION: CA19-9 can serve as an anchor marker for pancreatic cancer early detection applications.

Socioeconomic Disparities in Pancreas Cancer Resection and Survival in the Veterans Health Administration.

BACKGROUND: Disparities based on socioeconomic factors such as race, ethnicity, marital status, and insurance status are associated with pancreatic cancer resection, but these disparities are usually not observed for survival after resection. It is unknown if there are disparities when patients undergo their treatment in a non-fee-for-service, equal-access healthcare system such as the Veterans Health Administration (VHA). METHODS: Patients having T1-T3 M0 pancreatic adenocarcinoma diagnosed between 2006 and 2017 were identified from the VHA Corporate Data Warehouse. Socioeconomic, demographic, and tumor variables associated with resection and survival were assessed. RESULTS: In total, 2580 patients with early-stage pancreatic cancer were identified. The resection rate was 36.5%. Surgical resection was independently associated with younger age [odds ratio (OR) 0.94, p < 0.001], White race (OR 1.35, p = 0.028), married status (OR 1.85, p = 0.001), and employment status (retired vs. unemployed, OR 1.41, p = 0.008). There were no independent associations with Hispanic ethnicity, geographic region, or Social Deprivation Index. Resection was associated with significantly improved survival (median 21 vs. 8 months, p = 0.001). Among resected patients, survival was independently associated with younger age (HR 1.019, p = 0.002), geographic region (South vs. Pacific West, HR 0.721, p = 0.005), and employment (employed vs. unemployed, HR 0.752, p = 0.029). Race, Hispanic ethnicity, marital status, and Social Deprivation Index were not independently associated with survival after resection. CONCLUSIONS: Race, marital status, and employment status are independently associated with resection of pancreatic cancer in the VHA, whereas geographic region and employment status are independently associated with survival after resection. Further studies are warranted to determine the basis for these inequities.

Associations of gender, race, and ethnicity with disparities in short-term adverse outcomes after pancreatic resection for cancer.

BACKGROUND: Several studies have identified disparities in pancreatic cancer treatment associated with gender, race, and ethnicity. There are limited data examining disparities in short-term adverse outcomes after pancreatic resection for cancer. The aim of this study is to evaluate associations of gender, race, and ethnicity with morbidity and mortality after pancreatic resection for malignancy. METHODS: The American College of Surgeons National Surgical Quality Improvement database was retrospectively reviewed. The χ2 test and Student's t-test were used for univariable analysis and hierarchical logistic regression for multivariable analysis. RESULTS: Morbidity and major morbidity after pancreaticoduodenectomy are associated with male gender, Asian race, and Hispanic ethnicity, whereas 30-day mortality is associated with the male gender. Morbidity and major morbidity after distal pancreatectomy are associated with the male gender. Morbidity after pancreaticoduodenectomy is independently associated with male gender, Asian race, and Hispanic ethnicity; major morbidity is independently associated with male gender and Asian race, and mortality is independently associated with Hispanic ethnicity. CONCLUSIONS: Gender, race, and ethnicity are independently associated with morbidity after pancreaticoduodenectomy for cancer; gender and race are independently associated with major morbidity; and ethnicity is independently associated with mortality. Further studies are warranted to determine the basis of these associations.

AHPBA guidelines for managing VTE prophylaxis and anticoagulation for pancreatic surgery.

BACKGROUND: Major abdominal surgery and malignancy lead to a hypercoagulable state, with a risk of venous thromboembolism (VTE) of approximately 3% after pancreatic surgery. No guidelines exist to assist surgeons in managing VTE prophylaxis or anticoagulation in patients undergoing elective pancreatic surgery for malignancy or premalignant lesions. A systematic review specific to VTE prophylaxis and anticoagulation after resectional pancreatic surgery is herein provided. METHODS: Six topic areas are reviewed: pre- and perioperative VTE prophylaxis, early postoperative VTE prophylaxis, extended outpatient VTE prophylaxis, management of chronic anticoagulation, anti-coagulation after vascular reconstruction, and treatment of VTE. A Medline and PubMED search was completed with systematic medical literature review for each topic. Level of evidence was graded and strength of recommendation ranked according to the GRADE (Grades of Recommendation Assessment, Development and Evaluation) system for practice guidelines. RESULTS: Levels of evidence and strength of recommendations are presented. DISCUSSION: While strong data exist to guide management of chronic anticoagulation and treatment of VTE, data for anticoagulation after reconstruction is inconclusive and support for perioperative chemoprophylaxis with pancreatic surgery is similarly limited. The risk of post-pancreatectomy hemorrhage often exceeds that of thrombosis. The role of universal chemoprophylaxis must therefore be examined critically, particularly in the preoperative setting.

Racial Disparity in Pancreatoduodenectomy for Borderline Resectable Pancreatic Adenocarcinoma.

BACKGROUND: Previous studies have found racial disparity in pancreatectomies for resectable pancreatic adenocarcinoma. The aim of this study was to investigate if racial disparities were worse in the performance of pancreaticoduodenectomy for borderline resectable pancreatic adenocarcinoma. METHODS: This study used the National Cancer Database (2004-2016) and included patients with non-metastatic and head of the pancreas borderline resectable pancreatic adenocarcinoma. Multivariable, Poisson regression models with robust standard errors evaluated the relative risk (RR) of undergoing a pancreaticoduodenectomy among non-White patients (Black, Asian, and non-White Hispanic) compared with White patients. A Poisson regression model with hospital fixed effects was performed to evaluate if findings were due to within-hospital or between-hospital variation. Interaction between race and neoadjuvant therapy was also evaluated. RESULTS: There were 15,482 patients (median age 68 years, interquartile range 60-76 years; 48.6% male) with borderline resectable pancreatic adenocarcinoma who were predominantly White (84.3%, n = 13,058; non-White, 15.7%, n = 2424). Overall, 18.4% (n = 2853) had a pancreatic resection. Non-White patients had a significantly lower likelihood of undergoing a pancreatic resection for borderline resectable pancreatic adenocarcinoma when compared with White patients (RR 0.75, 95% confidence interval 0.68-0.83; p < 0.001). These findings persisted in the hospital fixed-effects model. In the interaction analysis, there were no significant differences in the likelihood of pancreatic resection if patients received neoadjuvant therapy. CONCLUSIONS: Non-White patients were 25% less likely to undergo a pancreatic resection for borderline resectable pancreatic adenocarcinoma compared with White patients. This racial disparity was due to variation in care within-hospitals and disappeared if non-White patients were treated with neoadjuvant therapy.

Pancreatic acinar cell carcinoma: A multi-center series on clinical characteristics and treatment outcomes.

BACKGROUND: Acinar cell carcinoma (ACC) is a very rare tumor of the exocrine pancreas, representing less than 1% of all pancreatic malignancies. The majority of data regarding ACC are limited to small case series. METHODS: This is a retrospective study conducted at a large healthcare system from 1996 to 2019. Patients with pathologically confirmed ACC were included, and demographic data, tumor characteristics, and treatment outcomes were abstracted by chart review. Survival curves were obtained by using the Kaplan-Meier method and compared using the log-rank test. RESULTS: Sixty-six patients with ACC were identified. The median patient age at diagnosis was 64, and 42% presented with metastatic disease. The majority presented with abdominal pain or pancreatitis (69%), and laboratory parameters did not correlate with tumor size, metastatic disease, or survival. Several somatic abnormalities were noted in tumors (BRCA2, TP53, and mismatch-repair genes). In patients with localized disease that underwent resection, the median time to develop metastatic lesions was 13 months. The median overall survival (OS) was 24.7 months from diagnosis, with a survival difference based on metastatic disease at diagnosis (median 15 vs 38 mos). Surgery was associated with improved survival in non-metastatic cases (p = 0.006) but not metastatic cases (p = 0.22), and chemotherapy showed OS benefit in metastatic disease (p < 0.01). Patients with metastatic ACC treated after 2010 utilized more platinum-based agents, and there was a OS benefit to FOLFOX or FOLFIRINOX chemotherapy compared to gemcitabine or capecitabine-based regimens (p = 0.006). CONCLUSION: Pancreatic ACC patients often present with advanced disease. Surgery was associated with survival benefit among patients presenting with localized disease. The use of FOLFOX or FOLFIRINOX chemotherapy regimens was associated with improved OS in metastatic patients. These data add to our knowledge in this rare malignancy, and improves understanding about the genomic underpinnings, prognosis and treatment for acinar cancers.

Temporal Assessment of Prognostic Factors in Patients With Pancreatic Ductal Adenocarcinoma Undergoing Neoadjuvant Treatment and Resection.

BACKGROUND: The clinicopathologic factors associated with the survival of patients with pancreatic ductal adenocarcinoma (PDAC) during the different phases of neoadjuvant treatment (NT)-at diagnosis, restaging, or postoperatively-remain unclear. METHODS: Data of patients with PDAC who underwent pancreatic resection after NT between 2008 and 2018 were retrospectively collected. Clinicopathologic characteristics and outcomes were compared stratified by resection margin status. Three multivariable regression models (at diagnosis, restaging, and postoperatively) were constructed to assess the temporal impact of different prognostic factors on all-cause survival (ACS) and disease-free survival (DFS). RESULTS: All patients were diagnosed with a nonmetastatic PDAC and were appropriate candidates for NT according to the current National Comprehensive Cancer Network guidelines. From a total of 83 patients, 57 (68.7%) had a negative resection margin >1 mm (R0), whereas 26 patients (31.3%) had a positive resection margin (R1). At diagnosis, planned procedure (P = 0.017) and CA19-9 >100 U/mL (P = 0.047) were independent prognostic factors of decreased ACS. At restaging, planned procedure (P = 0.017), FOLFIRINOX (P = 0.026), and tumor size >30 mm (P = 0.030) were independent prognostic factors for increased and decreased ACS, respectively. Postoperatively, R0 was an independent prognostic factor for improved ACS (P = 0.005) and DFS (P = 0.002), whereas adjuvant therapy (P = 0.006) was associated with increased ACS. Lymph node involvement (P = 0.019) was associated with decreased DFS. CONCLUSIONS: At diagnosis, restaging, and postoperatively, different, relevant clinicopathologic factors significantly impact the survival of patients with nonmetastatic PDAC undergoing NT. An R0 resection remains the most important prognostic factor and therefore should be the primary goal of surgical treatment in the neoadjuvant setting.

The improvement in post-operative mortality following pancreaticoduodenectomy between 2006 and 2016 is associated with an improvement in the ability to rescue patients after major morbidity, not in the rate of major morbidity.

BACKGROUND: The postoperative mortality rate of pancreaticoduodenectomy is decreasing over time. It is unknown whether this is related to reduction in incidence of major morbidity or failure to rescue. We aimed to make this determination. METHODS: ACS-NSQIP was retrospectively reviewed from 2006 to 2016. Comparisons were assessed with Spearman's rank-order correlation test, chi-square test with linear-by-linear association, and multivariable hierarchical logistic regression. RESULTS: Mortality decreased significantly from 2.9% to 1.5% (p < 0.001). This decrease was independent of preoperative variables on multivariable analysis (odds ratio [OR] 2.55, 95% confidence interval [CI] 1.55-5.21, p < 0.001). In contrast, no change in incidence of major morbidity was seen on univariable (26.8% to 25.9%, p = 1.00) or multivariable analysis (OR 1.22, 95% CI 1.03-1.45, p = 0.060). Failure to rescue was observed to decrease on univariable (9.8% to 4.1%, p < 0.001) and multivariable analysis (OR 3.65, 95% CI 2.07-6.76, p < 0.001). CONCLUSION: There has been a sizeable reduction in the mortality rate after pancreaticoduodenectomy from 2006 to 2016. This predominantly results from a reduction in failure to rescue rate rather than a decrease in incidence of major morbidity.

Neoadjuvant Therapy is Associated with Improved Survival in Borderline-Resectable Pancreatic Cancer.

BACKGROUND: Neoadjuvant therapy has shown value in various cancer types. The role of neoadjuvant therapy in pancreatic ductal adenocarcinoma (PDAC), however, remains unknown. The aim of the present work is to evaluate the effect of neoadjuvant therapy on the survival of patients with borderline-resectable PDAC. PATIENTS AND METHODS: Between 2004 and 2015, 7730 patients with resectable PDAC and 1980 patients with borderline-resectable PDAC were identified from the National Cancer Database (NCDB). Survival was compared between resectable and borderline-resectable patients. Survival and pathologic characteristics were also compared within borderline-resectable patients who received neoadjuvant therapy and those who received adjuvant therapy alone. Kaplan-Meier method and Cox proportional-hazard models were used for analysis. RESULTS: Median overall survival (mOS) of all patients with resectable PDAC was similar to that of patients with borderline-resectable disease treated with neoadjuvant therapy (26.5 versus 25.7 months, p = 0.78). Patients with borderline-resectable disease treated with neoadjuvant therapy had improved mOS compared with borderline-resectable patients treated with adjuvant therapy alone (25.7 versus 19.6 months, p < 0.0001). When comparing patients with borderline-resectable disease who received neoadjuvant therapy versus those who received adjuvant therapy alone, the former less often had node-positive pancreatic cancer (40.6% versus 76.3%, p < 0.001) and margin-positive resections (17.8% versus 44.4%, p < 0.001). CONCLUSION: Neoadjuvant therapy is associated with enhanced survival in patients with borderline-resectable pancreatic cancer, which may be attributed to tumor downstaging.

Germline cancer susceptibility gene variants, somatic second hits, and survival outcomes in patients with resected pancreatic cancer.

PURPOSE: Germline variants in double-strand DNA damage repair (dsDDR) genes (e.g., BRCA1/2) predispose to pancreatic adenocarcinoma (PDAC) and may predict sensitivity to platinum-based chemotherapy and poly(ADP) ribose polymerase (PARP) inhibitors. We sought to determine the prevalence and significance of germline cancer susceptibility gene variants in PDAC with paired somatic and survival analyses. METHODS: Using a customized next-generation sequencing panel, germline/somatic DNA was analyzed from 289 patients with resected PDAC ascertained without preselection for high-risk features (e.g., young age, personal/family history). All identified variants were assessed for pathogenicity. Outcomes were analyzed using multivariable-adjusted Cox proportional hazards regression. RESULTS: We found that 28/289 (9.7%; 95% confidence interval [CI] 6.5-13.7%) patients carried pathogenic/likely pathogenic germline variants, including 21 (7.3%) dsDDR gene variants (3 BRCA1, 4 BRCA2, 14 other dsDDR genes [ATM, BRIP1, CHEK2, NBN, PALB2, RAD50, RAD51C]), 3 Lynch syndrome, and 4 other genes (APC p.I1307K, CDKN2A, TP53). Somatic sequencing and immunohistochemistry identified second hits in the tumor in 12/27 (44.4%) patients with germline variants (1 failed sequencing). Compared with noncarriers, patients with germline dsDDR gene variants had superior overall survival (hazard ratio [HR] 0.54; 95% CI 0.30-0.99; P = 0.05). CONCLUSION: Nearly 10% of PDAC patients harbor germline variants, although the majority lack somatic second hits, the therapeutic significance of which warrants further study.

Lymph node metastases in resected pancreatic ductal adenocarcinoma: predictors of disease recurrence and survival.

BACKGROUND: Few studies have simultaneously assessed the prognostic value of the multiple classification systems for lymph node (LN) metastases in resected pancreatic ductal adenocarcinoma (PDAC). METHODS: In 600 patients with resected PDAC, we examined the association of LN parameters (AJCC 7th and 8th editions, LN ratio (LNR), and log odds of metastatic LN (LODDS)) with pattern of recurrence and patient survival using logistic regression and Cox proportional hazards regression, respectively. Regression models adjusted for age, sex, margin status, tumour grade, and perioperative therapy. RESULTS: Lymph node metastases classified by AJCC 7th and 8th editions, LNR, and LODDS were associated with worse disease free-survival (DFS) and overall survival (OS) (all Ptrend<0.01). American Joint Committee on Cancer 8th edition effectively predicted DFS and OS, while minimising model complexity. Lymph node metastases had weaker prognostic value in patients with positive margins and distal resections (both Pinteraction<0.03). Lymph node metastases by AJCC 7th and 8th editions did not predict the likelihood of local disease as the first site of recurrence. CONCLUSIONS: American Joint Committee on Cancer 8th edition LN classification is an effective and practical tool to predict outcomes in patients with resected PDAC. However, the prognostic value of LN metastases is attenuated in patients with positive resection margins and distal pancreatectomies.

Management of Neuroendocrine Tumor Liver Metastases: Long-Term Outcomes and Prognostic Factors from a Large Prospective Database.

BACKGROUND: Liver-directed therapies have been used to treat neuroendocrine liver metastases (NELM) for both symptomatic improvement and tumor growth control. We reviewed our experience with NELM to investigate the outcomes of available treatment modalities and to identify prognostic factors for survival. METHODS: We identified all patients with NELM, who were managed at our institution, from a prospectively collected institutional database. Overall survival (OS) was determined for each treatment modality. RESULTS: Between 2003 and 2010, we identified 939 patients with neuroendocrine tumors, of whom 649 patients had NELM. The primary tumor site was the small intestine in 245 patients (38%) and pancreas in 194 patients (30%). With a median follow-up of 44 months, the median, 5 and 10 year OS for each treatment group was as follows: hepatic resection (n = 58, 9%), 160 months, 90%, 70%; radiofrequency ablation (n = 28, 4%), 123 months, 84%, 55%; chemoembolization (n = 130, 20%), 66 months, 55%, 28%; systemic therapy (n = 316, 49%), 70 months, 58%, 31%; and observation (n = 117, 18%), 38 months, 38%, 20%. Age [hazard ratio (HR) 1.0, p < 0.001), small bowel primary site (HR 0.5, p < 0.001), hepatic resection (HR 0.3, p = 0.001), well-differentiated tumors (HR 0.3, p < 0.001), alkaline phosphatase within normal limit (WNL) (HR 0.4, p < 0.001), and chromogranin A WNL (HR 0.5, p < 0.001) were significant independent prognosticators for OS. CONCLUSIONS: This series represents one of the largest single-institution studies of NELM reported. We found that hepatic resection was associated with highly favorable OS. Our observations support hepatic resection in appropriately selected patients.

A standardized method for endoscopic necrosectomy improves complication and mortality rates.

OBJECTIVES: Endoscopic necrosectomy is effective in the treatment of walled-off necrosis (WON), and is preferred to surgical approaches, however complication and mortality rates remain high with few centers regularly employing the technique. Lack of a standardized approach may also contribute to these limitations. METHODS: Prior to the study, a multidisciplinary team applied standardized care assessment and management plan principles to develop and optimize a systematic approach for the management of WON. Preoperative, postoperative, and endoscopic management were standardized. Patient preparation, room set-up, technical features (EUS-guidance, cold-access with balloon dilation, fragmentation of necrosis on the initial procedure, antibiotic lavage, double pigtail stents), and discontinuation of PPIs to encourage auto-digestion of necrosis were included. This study employed a consecutive prospective clinical registry to assess the clinical outcomes of this standardized approach. RESULTS: 60 consecutive patients underwent 1.58 ± 0.1 necrosectomies, with debridement accomplished on the initial procedure in 98.3%. 39 patients (65%) required only one session. Clinical resolution occurred in 86.7%, with radiologic confirmation. Percutaneous drainage was required in 8 patients during follow-up, and 4 of these later required surgery. Serious adverse events occurred in 3.3% of patients, and there was no mortality. CONCLUSIONS: The standardized technique employed in this series was associated with lower rates of adverse events, morbidity, and mortality than prior large series. Use of a systematic approach, and integrating elements of this method may improve the risk profile of endoscopic necrosectomy and allow broader adoption.

Necrotizing pancreatitis: diagnosis, imaging, and intervention.

Acute necrotizing pancreatitis is a severe form of acute pancreatitis characterized by necrosis in and around the pancreas and is associated with high rates of morbidity and mortality. Although acute interstitial edematous pancreatitis is diagnosed primarily on the basis of signs, symptoms, and laboratory test findings, the diagnosis and severity assessment of acute necrotizing pancreatitis are based in large part on imaging findings. On the basis of the revised Atlanta classification system of 2012, necrotizing pancreatitis is subdivided anatomically into parenchymal, peripancreatic, and combined subtypes, and temporally into clinical early (within 1 week of onset) and late (>1 week after onset) phases. Associated collections are categorized as "acute necrotic" or "walled off" and can be sterile or infected. Imaging, primarily computed tomography and magnetic resonance imaging, plays an essential role in the diagnosis of necrotizing pancreatitis and the identification of complications, including infection, bowel and biliary obstruction, hemorrhage, pseudoaneurysm formation, and venous thrombosis. Imaging is also used to help triage patients and guide both temporizing and definitive management. A "step-up" method for the management of necrotizing pancreatitis that makes use of imaging-guided percutaneous catheter drainage of fluid collections prior to endoscopic or surgical necrosectomy has been shown to improve clinical outcomes. The authors present an algorithmic approach to the care of patients with necrotizing pancreatitis and review the use of imaging and interventional techniques in the diagnosis and management of this pathologic condition.

PD-1 Blockade Induces Reactivation of Nonproductive T-Cell Responses Characterized by NF-κB Signaling in Patients with Pancreatic Cancer.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) trials have evaluated CTLA-4 and/or PD-(L)1 blockade in patients with advanced disease in which bulky tumor burden and limited time to develop antitumor T cells may have contributed to poor clinical efficacy. Here, we evaluated peripheral blood and tumor T cells from patients with PDAC receiving neoadjuvant chemoradiation plus anti-PD-1 (pembrolizumab) versus chemoradiation alone. We analyzed whether PD-1 blockade successfully reactivated T cells in the blood and/or tumor to determine whether lack of clinical benefit could be explained by lack of reactivated T cells versus other factors. EXPERIMENTAL DESIGN: We used single-cell transcriptional profiling and TCR clonotype tracking to identify TCR clonotypes from blood that match clonotypes in the tumor. RESULTS: PD-1 blockade increases the flux of TCR clonotypes entering cell cycle and induces an IFNγ signature like that seen in patients with other GI malignancies who respond to PD-1 blockade. However, these reactivated T cells have a robust signature of NF-κB signaling not seen in cases of PD-1 antibody response. Among paired samples between blood and tumor, several of the newly cycling clonotypes matched activated T-cell clonotypes observed in the tumor. CONCLUSIONS: Cytotoxic T cells in the blood of patients with PDAC remain sensitive to reinvigoration by PD-1 blockade, and some have tumor-recognizing potential. Although these T cells proliferate and have a signature of IFN exposure, they also upregulate NF-κB signaling, which potentially counteracts the beneficial effects of anti-PD-1 reinvigoration and marks these T cells as non-productive contributors to antitumor immunity. See related commentary by Lander and DeNardo, p. 474.