Lhs1 dependent ERAD is determined by transmembrane domain context.

Transmembrane proteins have unique requirements to fold and integrate into the endoplasmic reticulum (ER) membrane. Most notably, transmembrane proteins must fold in three separate environments: extracellular domains fold in the oxidizing environment of the ER lumen, transmembrane domains (TMDs) fold within the lipid bilayer, and cytosolic domains fold in the reducing environment of the cytosol. Moreover, each region is acted upon by a unique set of chaperones and monitored by components of the ER associated quality control machinery that identify misfolded domains in each compartment. One factor is the ER lumenal Hsp70-like chaperone, Lhs1. Our previous work established that Lhs1 is required for the degradation of the unassembled α-subunit of the epithelial sodium channel (αENaC), but not the homologous ß- and γENaC subunits. However, assembly of the ENaC heterotrimer blocked the Lhs1-dependent ER associated degradation (ERAD) of the α-subunit, yet the characteristics that dictate the specificity of Lhs1-dependent ERAD substrates remained unclear. We now report that Lhs1-dependent substrates share a unique set of features. First, all Lhs1 substrates appear to be unglycosylated, and second they contain two TMDs. Each substrate also contains orphaned or unassembled TMDs. Additionally, interfering with inter-subunit assembly of the ENaC trimer results in Lhs1-dependent degradation of the entire complex. Finally, our work suggests that Lhs1 is required for a subset of ERAD substrates that also require the Hrd1 ubiquitin ligase. Together, these data provide hints as to the identities of as-yet unconfirmed substrates of Lhs1 and potentially of the Lhs1 homolog in mammals, GRP170.

US Medical Licensing Exam Performance and American Board of Surgery Qualifying and Certifying Examinations.

BACKGROUND: Program directors use US Medical Licensing Exam (USMLE) scores as criteria for ranking applicants. First-time pass rates of the American Board of Surgery (ABS) Qualifying (QE) and Certifying (CE) Examinations have become important measures of residency program quality. USMLE Step 1 will become pass/fail in 2022. STUDY DESIGN: American Board of Surgery QE and CE success rates were assessed considering multiple characteristics of highly ranked (top 20) applicants to 22 general surgery programs in 2011. Chi-square, t-test, Wilcoxon Rank sum, linear and logistic regression were used, as appropriate. RESULTS: The QE and CE first attempt pass rates were 96% (235/244) and 86% (190/221), respectively. QE/CE success was not significantly associated with sex, race, research experience, or publications. Alpha Omega Alpha (AΩA) status was associated with success on the index CE (98% vs 83%; p = 0.008). Step 1 and Step 2 Clinical Knowledge (CK) scores of surgeons who passed QE on their first attempt were higher than scores of those who failed (Step 1: 233 vs 218; p = 0.016); (Step 2CK: 244 vs 228, p = 0.009). For every 10-point increase in Step 1 and 2CK scores, the odds of passing CE on the first attempt increased 1.5 times (95% CI 1.12, 2.0; p = 0.006) and 1.5 times (95% CI 1.11, 2.02, p = 0.008), respectively. For every 10-point increase in Steps 1 and 2CK scores, the odds of passing the QE on the first attempt increased 1.85 times (95% CI 1.11, 3.09; p = 0.018) and 1.86 times (95% CI 1.14, 3.06, p = 0.013), respectively. CONCLUSIONS: USMLE Step 1 and Step 2 CK examination scores correlate with American Board of Surgery QE and CE performance and success. The USMLE decision to transition Step 1 to a pass/fail examination will require program directors to identify other factors that predict ABS performance for ranking applicants.

Circulating miRNA in Patients Undergoing Total Pancreatectomy and Islet Autotransplantation.

Circulating microRNAs (miRNAs) can be biomarkers for diagnosis and progression of several pathophysiological conditions. In a cohort undergoing total pancreatectomy with islet autotransplantation (TPIAT) from the multicenter Prospective Observational Study of TPIAT (POST), we investigated associations between a panel of circulating miRNAs (hsa-miR-375, hsa-miR-29b-3p, hsa-miR-148a-3p, hsa-miR-216a-5p, hsa-miR-320d, hsa-miR-200c, hsa-miR-125b, hsa-miR-7-5p, hsa-miR-221-3p, hsa-miR-122-5p) and patient, disease and islet-isolation characteristics. Plasma samples (n = 139) were collected before TPIAT and miRNA levels were measured by RTPCR. Disease duration, prior surgery, and pre-surgical diabetes were not associated with circulating miRNAs. Levels of hsa-miR-29b-3p (P = 0.03), hsa-miR-148a-3p (P = 0.04) and hsa-miR-221-3p (P = 0.01) were lower in those with genetic risk factors. Levels of hsa-miR-148a-3p (P = 0.04) and hsa-miR-7-5p (P = 0.04) were elevated in toxic/metabolic disease. Participants with exocrine insufficiency had lower hsa-miR-29b-3p, hsa-miR-148a-3p, hsa-miR-320d, hsa-miR-221-3p (P < 0.01) and hsa-miR-375, hsa-miR-200c-3p, and hsa-miR-125b-5p (P < 0.05). Four miRNAs were associated with fasting C-peptide before TPIAT (hsa-miR-29b-3p, r = 0.18; hsa-miR-148a-3p, r = 0.21; hsa-miR-320d, r = 0.19; and hsa-miR-221-3p, r = 0.21; all P < 0.05), while hsa-miR-29b-3p was inversely associated with post-isolation islet equivalents/kg and islet number/kg (r = -0.20, P = 0.02). Also, hsa-miR-200c (r = 0.18, P = 0.03) and hsa-miR-221-3p (r = 0.19, P = 0.03) were associated with islet graft tissue volume. Further investigation is needed to determine the predictive potential of these miRNAs for assessing islet autotransplant outcomes.

Artificial Intelligence and Echocardiography: A Primer for Cardiac Sonographers.

Artificial intelligence (AI) is emerging as a key component in diagnostic medical imaging, including echocardiography. AI with deep learning has already been used with automated view labeling, measurements, and interpretation. As the development and use of AI in echocardiography increase, potential concerns may be raised by cardiac sonographers and the profession. This report, from a sonographer's perspective, focuses on defining AI, the basics of the technology, identifying some current applications of AI, and how the use of AI may improve patient care in the future.

Islet Harvest in Carbon Monoxide-Saturated Medium for Chronic Pancreatitis Patients Undergoing Islet Autotransplantation.

Stresses encountered during human islet isolation lead to unavoidable ß-cell death after transplantation. This reduces the chance of insulin independence in chronic pancreatitis patients undergoing total pancreatectomy and islet autotransplantation. We tested whether harvesting islets in carbon monoxide-saturated solutions is safe and can enhance islet survival and insulin independence after total pancreatectomy and islet autotransplantation. Chronic pancreatitis patients who consented to the study were randomized into carbon monoxide (islets harvested in a carbon monoxide-saturated medium) or control (islets harvested in a normal medium) groups. Islet yield, viability, oxygen consumption rate, ß-cell death (measured by unmethylated insulin DNA), and serum cytokine levels were measured during the peri-transplantation period. Adverse events, metabolic phenotypes, and islet function were measured prior and at 6 months post-transplantation. No adverse events directly related to the infusion of carbon monoxide islets were observed. Carbon monoxide islets showed significantly higher viability before transplantation. Subjects receiving carbon monoxide islets had less ß-cell death, decreased CCL23, and increased CXCL12 levels at 1 or 3 days post transplantation compared with controls. Three in 10 (30%) of the carbon monoxide subjects and none of the control subjects were insulin independent. This pilot trial showed for the first time that harvesting human islets in carbon monoxide-saturated solutions is safe for total pancreatectomy and islet autotransplantation patients.

A Study on the Effect of Patient Characteristics, Geographical Utilization, and Patient Outcomes for Total Pancreatectomy Alone and Total Pancreatectomy With Islet Autotransplantation in Patients With Pancreatitis in the United States.

OBJECTIVES: A selective therapy for pancreatitis is total pancreatectomy and islet autotransplantation. Outcomes and geographical variability of patients who had total pancreatectomy (TP) alone or total pancreatectomy with islet autotransplantation (TPIAT) were assessed. METHODS: Data were obtained from the Healthcare Cost and Utilization Project National Inpatient Sample database. Weighed univariate and multivariate analyses were performed to determine the effect of measured variables on outcomes. RESULTS: Between 2002 and 2013, there were 1006 TP and 825 TPIAT in patients with a diagnosis of chronic pancreatitis, and 1705 TP and 830 TPIAT for any diagnosis of pancreatitis. The majority of the TP and TPIAT were performed in larger urban hospitals. Costs were similar for TP and TPIAT for chronic pancreatitis but were lower for TPIAT compared with TP for any type of pancreatitis. The trend for TP and TPIAT was significant in all geographical areas during the study period. CONCLUSIONS: There is an increasing trend of both TP and TPIAT. Certain groups are more likely to be offered TPIAT compared with TP alone. More data are needed to understand disparities and barriers to TPIAT, and long-term outcomes of TPIAT such as pain control and glucose intolerance need further study.

Mesenchymal Stem Cells from Chronic Pancreatitis Patients Show Comparable Potency Compared to Cells from Healthy Donors.

Mesenchymal stem cells (MSCs) are proven to be beneficial in islet transplantation, suggesting a potential therapeutic role of them in total pancreatectomy with islet autotransplantation (TP-IAT) for chronic pancreatitis (CP) patients. We investigated whether MSCs derived from CP patients are suitable for use in autologous cell therapy. MSCs from healthy donors (H-MSCs) and CP patients (CP-MSCs) were studied for phenotype, colony formation potential, multilineage differentiation ability, proliferation, senescence, secretory characters, and immunosuppressive functions. The potential protective effect of CP-MSCs was evaluated on hypoxia-induced islet cell death. Cell surface markers were similar between H-MSCs and CP-MSCs, as well as the ability of colony formation, multilineage differentiation, secretion of vascular endothelial growth factor and transforming growth factor (TGF-ß), senescence, and inhibition of T cells proliferation in vitro. We found that growth differentiation factor 6 and hepatocyte growth factor (HGF) were significantly downregulated, whereas TGFß and matrix metalloproteinase-2 were significantly upregulated in CP-MSCs compared with H-MSCs, among 84 MSC-related genes investigated in this study. MSCs from CP patients secreted less HGF, compared with the H-MSCs. A higher interferon-γ-induced indoleamine 2,3-dioxygenase expression was observed in CP-MSCs compared to H-MSCs. Moreover, CP-MSCs prevented hypoxia-induced ß cell deaths to a similar extent as H-MSCs. Regardless of moderate difference in gene expression, CP-MSCs possess similar immunomodulatory and prosurvival functions to H-MSCs, and may be suitable for autologous cell therapy in CP patients undergoing TP-IAT. Stem Cells Translational Medicine 2019;8:418-429.

The Impact of Endoscopic Retrograde Cholangiopancreatography on Islet Cell Yield During Total Pancreatectomy With Islet Autotransplantation.

OBJECTIVES: Many patients with recurrent acute and chronic pancreatitis who are candidates for total pancreatectomy and islet cell autotransplantation (TPIAT) undergo endoscopic retrograde cholangiopancreatography (ERCP). However, little is known on the impact of ERCP on TPIAT outcomes. We aimed to explore the effect of antecedent ERCP on islet yield and postoperative insulin requirement after TPIAT. METHODS: Through a prospectively maintained database, we identified patients who underwent TPIAT at our institution between 2009 and 2016. After adjusting for confounders, islet cell yield and postoperative insulin requirement were compared between subjects who did and did not undergo ERCP within 2 years prior to TPIAT. RESULTS: Data were available on 167 TPIAT patients during the study period; 105 (62.9%) had undergone ERCP within 2 years prior. Prior ERCP was not associated with a reduction in islet equivalents per patient kilogram (odds ratio, 1.37; 95% confidence interval, 0.75-2.5; P = 0.31). Antecedent ERCP was not associated with increased postoperative insulin requirement among patients with no diabetes undergoing TPIAT (odds ratio, 0.85; 95% confidence interval, 0.39-1.83; P = 0.67). CONCLUSIONS: Antecedent ERCP does not appear to have a deleterious impact on islet cell yield during TPIAT. Additional multicenter data are needed to more clearly determine the impact of ERCP in this context.

Patient Selection for Total Pancreatectomy with Islet Autotransplantation in the Surgical Management of Chronic Pancreatitis.

BACKGROUND: Best practice to select patients with chronic pancreatitis for surgical management with total pancreatectomy with islet autotransplantation (TPIAT) is in evolution as new discoveries are made in the pathogenesis of chronic pancreatitis. STUDY DESIGN: A prospectively maintained database of patients undergoing TPIAT was reviewed. Islet function was inferred from daily insulin requirement. Pain relief was evaluated by healthcare use and narcotic use. Quality of life (QOL) was measured with the RAND 12-Item Short Form Survey. RESULTS: One hundred and ninety-five patients (141 women, aged 40.3 years, BMI 26.5 kg/m2) underwent TPIAT. Mean duration of disease before operation was 8.1 years. Fifty-six (29%) patients had pancreatic operations before TPIAT, 37 (19%) patients were diabetic preoperatively, and 52 (27%) patients were smokers. A mean of 3,253 islet equivalents transplanted/kg were harvested. Insulin independence was achieved in 29%, 28%, and 23% of patients at 1, 2, and 5 years postoperative. Nonsmokers with a shorter duration of chronic pancreatitis and no earlier pancreas operation were more likely to be insulin free. Median number of preoperative emergency department visits and hospitalizations were 6.6 and 4.3 annually, respectively, compared with 0 at 1, 2, and 5 years postoperative. Median oral morphine equivalents were 214 mg/kg preoperation and 60, 64, 69, at 1, 2, 5 years postoperative. Preoperative, 1, 2, 5 years postoperative QOL scores were 29, 36, 34, and 33 (physical; p < 0.01) and 39, 44, 42, and 42 (mental health; p < 0.02). Genetic pancreatitis patients were more often narcotic free and had better QOL than patients with pancreatitis of other causes. At 5 years, overall survival was 92.3%. CONCLUSIONS: Total pancreatectomy with islet autotransplantation is a durable operation, with islet function, pain relief, and QOL improvements persisting to 5 years postoperative. Patients with genetic pancreatitis, short duration of disease, and nonsmokers have superior outcomes.

Autologous Mesenchymal Stem Cell and Islet Cotransplantation: Safety and Efficacy.

Islet engraftment after transplantation is impaired by high rates of islet/ß cell death caused by cellular stressors and poor graft vascularization. We studied whether cotransplantation of ex vivo expanded autologous bone marrow-derived mesenchymal stem cells (MSCs) with islets is safe and beneficial in chronic pancreatitis patients undergoing total pancreatectomy with islet autotransplantation. MSCs were harvested from the bone marrow of three islet autotransplantation patients and expanded at our current Good Manufacturing Practices (cGMP) facility. On the day of islet transplantation, an average dose of 20.0 ± 2.6 ×106 MSCs was infused with islets via the portal vein. Adverse events and glycemic control at baseline, 6, and 12 months after transplantation were compared with data from 101 historical control patients. No adverse events directly related to the MSC infusions were observed. MSC patients required lower amounts of insulin during the peritransplantation period (p = .02 vs. controls) and had lower 12-month fasting blood glucose levels (p = .02 vs. controls), smaller C-peptide declines over 6 months (p = .01 vs. controls), and better quality of life compared with controls. In conclusion, our pilot study demonstrates that autologous MSC and islet cotransplantation may be a safe and potential strategy to improve islet engraftment after transplantation. (Clinicaltrials.gov registration number: NCT02384018). Stem Cells Translational Medicine 2018;7:11-19.

Adipose stem cells from chronic pancreatitis patients improve mouse and human islet survival and function.

BACKGROUND: Chronic pancreatitis has surgical options including total pancreatectomy to control pain. To avoid surgical diabetes, the explanted pancreas can have islets harvested and transplanted. Immediately following total pancreatectomy with islet autotransplantation (TP-IAT), many islet cells die due to isolation and transplantation stresses. The percentage of patients remaining insulin free after TP-IAT is therefore low. We determined whether cotransplantation of adipose-derived mesenchymal stem cells (ASCs) from chronic pancreatitis patients (CP-ASCs) would protect islets after transplantation. METHODS: In a marginal mass islet transplantation model, islets from C57BL/6 mice were cotransplanted with CP-ASCs into syngeneic streptozotocin-treated diabetic mice. Treatment response was defined by the percentage of recipients reaching normoglycemia, and by the area under the curve for glucose and c-peptide in a glucose tolerance test. Macrophage infiltration, ß-cell apoptosis, and islet graft vasculature were measured in transplanted islet grafts by immunohistochemistry. mRNA expression profiling of 84 apoptosis-related genes in islet grafts transplanted alone or with CP-ASCs was measured by the RT2 Profiler™ Apoptosis PCR Array. The impact of insulin-like growth factor-1 (IGF-1) on islet apoptosis was determined in islets stimulated with cytokines (IL-1ß and IFN-γ) in the presence and absence of CP-ASC conditioned medium. RESULTS: CP-ASC-treated mice were more often normoglycemic compared to mice receiving islets alone. ASC cotransplantation reduced macrophage infiltration, ß-cell death, suppressed expression of TNF-α and Bcl-2 modifying factor (BMF), and upregulated expressions of IGF-1 and TNF Receptor Superfamily Member 11b (TNFRSF11B) in islet grafts. Islets cultured in conditioned medium from CP-ASCs showed reduced cell death. This protective effect was diminished when IGF-1 was blocked in the conditioned medium by the anti-IGF-1 antibody. CONCLUSION: Cotransplantation of islets with ASCs from the adipose of chronic pancreatitis patients improved islet survival and islet function after transplantation. The effects are in part mediated by paracrine secretion of IGF-1, suppression of inflammation, and promotion of angiogenesis. ASCs from chronic pancreatitis patients have the potential to be used as a synergistic therapy to enhance the efficacy of islet transplantation following pancreatectomy.

Adipose Stem Cell Therapy Mitigates Chronic Pancreatitis via Differentiation into Acinar-like Cells in Mice.

The objective of this study was to assess the capacity of adipose-derived mesenchymal stem cells (ASCs) to mitigate disease progression in an experimental chronic pancreatitis mouse model. Chronic pancreatitis (CP) was induced in C57BL/6 mice by repeated ethanol and cerulein injection, and mice were then infused with 4 × 105 or 1 × 106 GFP+ ASCs. Pancreas morphology, fibrosis, inflammation, and presence of GFP+ ASCs in pancreases were assessed 2 weeks after treatment. We found that ASC infusion attenuated pancreatic damage, preserved pancreas morphology, and reduced pancreatic fibrosis and cell death. GFP+ ASCs migrated to pancreas and differentiated into amylase+ cells. In further confirmation of the plasticity of ASCs, ASCs co-cultured with acinar cells in a Transwell system differentiated into amylase+ cells with increased expression of acinar cell-specific genes including amylase and chymoB1. Furthermore, culture of acinar or pancreatic stellate cell lines in ASC-conditioned medium attenuated ethanol and cerulein-induced pro-inflammatory cytokine production in vitro. Our data show that a single intravenous injection of ASCs ameliorated CP progression, likely by directly differentiating into acinar-like cells and by suppressing inflammation, fibrosis, and pancreatic tissue damage. These results suggest that ASC cell therapy has the potential to be a valuable treatment for patients with pancreatitis.

The Impact of Cholecystectomy After Endoscopic Sphincterotomy for Complicated Gallstone Disease.

OBJECTIVES: Cholecystectomy after endoscopic sphincterotomy (ES) is associated with improved outcomes compared to ES alone, however randomized trials have included mainly fit surgical candidates. Our objective was to assess the impact of cholecystectomy after ES among elderly patients, in whom the perceived risks of surgery may be increased and the prevailing bias may be to defer cholecystectomy. METHODS: We performed adjusted analyses comparing clinical outcomes in patients ≥65 years of age who did and did not undergo follow-up cholecystectomy after endoscopic sphincterotomy for choledocholithiasis, ascending cholangitis, or gallstone pancreatitis. We also compared adverse events between the two groups. RESULTS: In the ES alone group, 39.3% of patients experienced a recurrent complication compared with 18.0% in the ES and cholecystectomy group. After adjusting for comorbidities using multivariable regression, cholecystectomy in addition to ES was associated with a reduced risk of recurrent choledocholithiasis (OR 0.38, 95%CI 0.34-0.42, P<0.001), ascending cholangitis (OR 0.28, 95%CI 0.23-0.34, P<0.001), and gallstone pancreatitis (OR 0.35, 95%CI 0.24-0.49, P<0.001) compared to ES alone. This benefit was preserved after propensity score adjustment, in patients ≥75 years of age, and in those with major comorbidities including cancer, heart failure, and liver disease. Serious post-operative complications such as myocardial infarction, pulmonary embolism, and pneumonia were not more common in the cholecystectomy group. CONCLUSIONS: Among older patients, including those with serious comorbidities, cholecystectomy after endoscopic sphincterotomy was associated with a significant and clinically important reduction in recurrent complications compared to sphincterotomy alone. This benefit did not appear to be outweighed by surgical complications, highlighting the importance of cholecystectomy, even in elderly patients whose lifespans may be limited by unrelated conditions.

A Prospective Randomized Multicenter Trial of Distal Pancreatectomy With and Without Routine Intraperitoneal Drainage.

OBJECTIVE: The objective of this study was to test the hypothesis that distal pancreatectomy (DP) without intraperitoneal drainage does not affect the frequency of grade 2 or higher grade complications. BACKGROUND: The use of routine intraperitoneal drains during DP is controversial. Prior to this study, no prospective trial focusing on DP without intraperitoneal drainage has been reported. METHODS: Patients undergoing DP for all causes at 14 high-volume pancreas centers were preoperatively randomized to placement of a drain or no drain. Complications and their severity were tracked for 60 days and mortality for 90 days. The study was powered to detect a 15% positive or negative difference in the rate of grade 2 or higher grade complications. All data were collected prospectively and source documents were reviewed at the coordinating center to confirm completeness and accuracy. RESULTS: A total of 344 patients underwent DP with (N = 174) and without (N = 170) the use of intraperitoneal drainage. There were no differences between cohorts in demographics, comorbidities, pathology, pancreatic duct size, pancreas texture, or operative technique. There was no difference in the rate of grade 2 or higher grade complications (44% vs. 42%, P = 0.80). There was no difference in clinically relevant postoperative pancreatic fistula (18% vs 12%, P = 0.11) or mortality (0% vs 1%, P = 0.24). DP without routine intraperitoneal drainage was associated with a higher incidence of intra-abdominal fluid collection (9% vs 22%, P = 0.0004). There was no difference in the frequency of postoperative imaging, percutaneous drain placement, reoperation, readmission, or quality of life scores. CONCLUSIONS: This prospective randomized multicenter trial provides evidence that clinical outcomes are comparable in DP with or without intraperitoneal drainage.

α-1 Antitrypsin Enhances Islet Engraftment by Suppression of Instant Blood-Mediated Inflammatory Reaction.

Islet cell transplantation has limited effectiveness because of an instant blood-mediated inflammatory reaction (IBMIR) that occurs immediately after cell infusion and leads to dramatic ß-cell death. In intraportal islet transplantation models using mouse and human islets, we demonstrated that α-1 antitrypsin (AAT; Prolastin-C), a serine protease inhibitor used for the treatment of AAT deficiency, inhibits IBMIR and cytokine-induced inflammation in islets. In mice, more diabetic recipients reached normoglycemia after intraportal islet transplantation when they were treated with AAT compared with mice treated with saline. AAT suppressed blood-mediated coagulation pathways by diminishing tissue factor production, reducing plasma thrombin-antithrombin complex levels and fibrinogen deposition on islet grafts, which correlated with less graft damage and apoptosis. AAT-treated mice showed reduced serum tumor necrosis factor-α levels, decreased lymphocytic infiltration, and decreased nuclear factor (NF)-κB activation compared with controls. The potent anti-inflammatory effect of AAT is possibly mediated by suppression of c-Jun N-terminal kinase (JNK) phosphorylation. Blocking JNK activation failed to further reduce cytokine-induced apoptosis in ß-cells. Taken together, AAT significantly improves islet graft survival after intraportal islet transplantation by mitigation of coagulation in IBMIR and suppression of cytokine-induced JNK and NF-κB activation. AAT-based therapy has the potential to improve graft survival in human islet transplantation and other cellular therapies on the horizon.

Prognostic Value of Lymph Node Status and Extent of Lymphadenectomy in Pancreatic Neuroendocrine Tumors Confined To and Extending Beyond the Pancreas.

BACKGROUND: The impact of lymph node (LN) status and lymphadenectomy (LA) on survival in pancreatic neuroendocrine tumors (pNETs) remains controversial. We evaluated the impact of tumor extension and grade on nodal metastasis and survival. METHODS: Surgical pNET patients were queried in the Surveillance Epidemiology and End Results (SEER) database (1998-2012, N = 981). Factors associated with LN status were analyzed by logistic regression and by Cox analyses. RESULTS: For T1-T2 tumors, N status was associated only with tumor size. N status (p = 0.001), grade (p < 0.001), age (p = 0.001), and sex (p = 0.007) predicted overall survival (OS). For T3-T4, grade (p < 0.001), sex (p = 0.004), size (p = 0.013), and age (p = 0.007) but not N status (p = 0.789) predicted OS. For T1-T2, disease-specific survival (DSS; p = 0.003) and OS (p = 0.008) were longer for N0 vs N1, while N0 vs NX had similar OS (p = 0.59) and DSS (p = 0.80). While a difference was seen in DSS for NX vs N1 (p = 0.04), no significant difference in OS was seen (p = 0.08). For T3-T4, N status did not affect DSS (p = 0.365) or OS (p = 0.454). For all T groups and any N status, extended LA (≥10 nodes resected) was not associated with OS. CONCLUSION: While in T1-T2 pNET N1 status is a predictor of negative OS, similar outcome between NX and N0 supports limited LN resection in selected patients. Extended LA is unlikely to be helpful in T3-T4.