Group XIV C-type lectins: emerging targets in tumor angiogenesis.

C-type lectins, distinguished by a C-type lectin binding domain (CTLD), are an evolutionarily conserved superfamily of glycoproteins that are implicated in a broad range of physiologic processes. The group XIV subfamily of CTLDs are comprised of CD93, CD248/endosialin, CLEC14a, and thrombomodulin/CD141, and have important roles in creating and maintaining blood vessels, organizing extracellular matrix, and balancing pro- and anti-coagulative processes. As such, dysregulation in the expression and downstream signaling pathways of these proteins often lead to clinically relevant pathology. Recently, group XIV CTLDs have been shown to play significant roles in cancer progression, namely tumor angiogenesis and metastatic dissemination. Interest in therapeutically targeting tumor vasculature is increasing and the search for novel angiogenic targets is ongoing. Group XIV CTLDs have emerged as key moderators of tumor angiogenesis and metastasis, thus offering substantial therapeutic promise for the clinic. Herein, we review our current knowledge of group XIV CTLDs, discuss each's role in malignancy and associated potential therapeutic avenues, briefly discuss group XIV CTLDs in the context of two other relevant lectin families, and offer future direction in further elucidating mechanisms by which these proteins function and facilitate tumor growth.

Neoadjuvant Chemotherapy Versus Upfront Surgery for Resectable Pancreatic Adenocarcinoma: An Updated Nationwide Study.

OBJECTIVE: The objective of this study was to assess the association of survival with neoadjuvant chemotherapy (NAC) in resectable pancreatic adenocarcinoma (PDAC). BACKGROUND: The early control of potential micrometastases and patient selection using NAC has been advocated for patients with PDAC. However, the role of NAC for resectable PDAC remains unclear. METHODS: Patients with clinical T1 and T2 PDAC were identified in the National Cancer Database from 2010 to 2017. Kaplan-Meier estimates, and Cox regression models were used to compare survival. To address immortal time bias, landmark analysis was performed. Interactions between preoperative factors and NAC were investigated in subgroup analyses. A propensity score analysis was performed to compare survival between multiagent NAC and upfront surgery. RESULTS: In total, 4041 patients were treated with upfront surgery and 1,175 patients were treated with NAC (79.4% multiagent NAC, 20.6% single-agent NAC). Using a landmark time of 6 months after diagnosis, patients treated with multiagent NAC had longer median overall survival compared with upfront surgery and single-agent NAC. (35.8 vs 27.1 vs 27.4 mo). Multiagent NAC was associated with lower mortality rates compared with upfront surgery (adjusted hazard ratio, 0.77; 95% CI, 0.70-0.85), whereas single-agent NAC was not. The association of survival with multiagent NAC were consistent in analyses using the matched data sets. Interaction analysis revealed that the association between multiagent NAC and a lower mortality rate did not significantly differ across age, facility type, tumor location, CA 19-9 levels, and clinical T/N stages. CONCLUSIONS: The findings suggest that multiagent NAC followed by resection is associated with improved survival compared with upfront surgery.

Intraoperative pancreatoscopy can improve the detection of skip lesions during surgery for intraductal papillary mucinous neoplasia: A pilot study.

OBJECTIVES: Intraoperative pancreatoscopy is a promising procedure that might guide surgical resection for suspected main duct (MD) and mixed type (MT) intraductal papillary mucinous neoplasms (IPMNs). The aim of the present study was to assess the diagnostic yield and clinical impact of intraoperative pancreatoscopy in patients operated on for MD and MT-IPMNs. METHODS: This is a retrospective cohort study. Patients undergoing surgery for suspected MD or MT-IPMN underwent intraoperative pancreatoscopy and frozen section analysis. In all patients who required extended resection due to pancreatoscopic findings, we compared the final histology with the results of the intraoperative frozen section analysis. RESULTS: In total, 46 patients, 48% females, mean age (range) 67 years (45-82 years) underwent intraoperative pancreatoscopy. No mortality or procedure related complications were observed. Pancreatoscopy changed the operative course in 30 patients (65%), leading to extended resections in 20 patients (43%) and to parenchyma sparing procedures in 10 patients (22%). Analyzing the group of patients who underwent extended resections, 7 (35%) displayed lesions that needed further surgical treatment (six high grade dysplasia and one with G1 pancreatic neuroendocrine tumor) and among those 7, just 1 (14%) would have been detected exclusively with histological frozen section analysis of the transection margin. The combination of both pancreatoscopy and frozen section analysis lead to 86% sensitivity and 92% specificity for the detection of pathological tissue in the remnant pancreas. CONCLUSION: Intraoperative pancreatoscopy is a safe and feasible procedure and might allow the detection of skip lesions during surgery for suspect MD-involving IPMNs.

Unmeasured factors are associated with the use of completion lymph node dissection (CLND) in melanoma.

BACKGROUND: Completion lymph node dissection (CLND) was the standard treatment for patients with melanoma with positive sentinel lymph nodes (SLN) until 2017 when data from the DeCOG-SLT and MLST-2 randomized trials challenged the survival benefit of this procedure. We assessed the contribution of patient, tumor and facility factors on the use of CLND in patients with surgically resected Stage III melanoma. METHODS: Using the National Cancer Database, patients who underwent surgical excision and were found to have a positive SLN from 2012 to 2017 were included. A multivariable mixed-effects logistic regression model with a random intercept for the facility was used to determine the effect of patient, tumor, and facility variables on the risk of CLND. Reference effect measures (REMs) were used to compare the contribution of contextual effects (unknown facility variables) versus measured variables on the variation in CLND use. RESULTS: From 2012 to 2017, the overall use of CLND decreased from 59.9% to 26.5% (p < 0.0001). Overall, older patients and patients with government-based insurance were less likely to undergo CLND. Tumor factors associated with a decreased rate of CLND included primary tumor location on the lower limb, decreasing depth, and mitotic rate <1. However, the contribution of contextual effects to the variation in CLND use exceeded that of the measured facility, tumor, time, and patient variables. CONCLUSIONS: There was a decrease in CLND use during the study period. However, there is still high variability in CLND use, mainly driven by unmeasured contextual effects.

Atypical chemokine receptors: emerging therapeutic targets in cancer.

Atypical chemokine receptors (ACKRs) regulate the availability of chemokines via chemokine scavenging, while also having the capacity to elicit downstream function through ß-arrestin coupling. This contrasts with conventional chemokine receptors that directly elicit immune cell migration through G protein-coupled signaling. The significance of ACKRs in cancer biology has previously been poorly understood, but recent findings have highlighted the multifaceted role of these receptors in tumorigenesis and immune response modulation within the tumor microenvironment (TME). Additionally, recent research has expanded our understanding of the function of several receptors including GPR182, CCRL2, GPR1, PITPNM3, and C5aR2 that share similarities with the ACKR family. In this review, we discuss these recent developments, and highlight the opportunities and challenges of pharmacologically targeting ACKRs in cancer.

Circulating CD8+ mucosal-associated invariant T cells correlate with improved treatment responses and overall survival in anti-PD-1-treated melanoma patients.

OBJECTIVES: While much of the research concerning factors associated with responses to immune checkpoint inhibitors (ICIs) has focussed on the contributions of conventional peptide-specific T cells, the role of unconventional T cells, such as mucosal-associated invariant T (MAIT) cells, in human melanoma remains largely unknown. MAIT cells are an abundant population of innate-like T cells expressing a semi-invariant T-cell receptor restricted to the MHC class I-like molecule, MR1, presenting vitamin B metabolites derived from bacteria. We sought to characterise MAIT cells in melanoma patients and determined their association with treatment responses and clinical outcomes. METHODS: In this prospective clinical study, we analysed the frequency and functional profile of circulating and tumor-infiltrating MAIT cells in human melanoma patients. Using flow cytometry, we compared these across metastatic sites and between ICI responders vs. non-responders as well as healthy donors. RESULTS: We identified tumor-infiltrating MAIT cells in melanomas across metastatic sites and found that the number of circulating MAIT cells is reduced in melanoma patients compared to healthy donors. However, circulating MAIT cell frequencies are restored by ICI treatment in responding patients, correlating with treatment responses, in which patients with high frequencies of MAIT cells exhibited significantly improved overall survival. CONCLUSION: Our results suggest that MAIT cells may be a potential predictive marker of responses to immunotherapies and provide rationale for testing MAIT cell-directed therapies in combination with current and next-generation ICIs.

GPR182 limits antitumor immunity via chemokine scavenging in mouse melanoma models.

For many solid tumors, immune checkpoint blockade therapy has become first line treatment, yet a large proportion of patients with immunologically cold tumors do not benefit due to the paucity of tumor infiltrating lymphocytes. Here we show that the orphan G Protein-Coupled Receptor 182 (GPR182) contributes to immunotherapy resistance in cancer via scavenging chemokines that are important for lymphocyte recruitment to tumors. GPR182 is primarily upregulated in melanoma-associated lymphatic endothelial cells (LECs) during tumorigenesis, and this atypical chemokine receptor endocytoses chemokines promiscuously. In GPR182-deficient mice, T cell infiltration into transplanted melanomas increases, leading to enhanced effector T cell function and improved antitumor immunity. Ablation of GPR182 leads to increased intratumoral concentrations of multiple chemokines and thereby sensitizes poorly immunogenic tumors to immune checkpoint blockade and adoptive cellular therapies. CXCR3 blockade reverses the improved antitumor immunity and T cell infiltration characteristic of GPR182-deficient mice. Our study thus identifies GPR182 as an upstream regulator of the CXCL9/CXCL10/CXCR3 axis that limits antitumor immunity and as a potential therapeutic target in immunologically cold tumors.

Prognosis Based Definition of Resectability in Pancreatic Cancer: A Road Map to New Guidelines.

OBJECTIVE: To identify objective preoperative prognostic factors that are able to predict long-term survival of patients affected by PDAC. SUMMARY OF BACKGROUND DATA: In the modern era of improved systemic chemotherapy for PDAC, tumor biology, and response to chemotherapy are essential in defining prognosis and an improved approach is needed for classifying resectability beyond purely anatomic features. METHODS: We queried the National Cancer Database regarding patients diagnosed with PDAC from 2010 to 2016. Cox proportional hazard models were used to select preoperative baseline factors significantly associated with survival; final models for overall survival (OS) were internally validated and formed the basis of the nomogram. RESULTS: A total of 7849 patients with PDAC were included with a median follow-up of 19 months. On multivariable analysis, factors significantly associated with OS included carbohydrate antigen 19-9, neoadjuvant treatment, tumor size, age, facility type, Charlson/Deyo score, primary site, and sex; T4 stage was not independently associated with OS. The cumulative score was used to classify patients into 3 groups: good, intermediate, and poor prognosis, respectively. The strength of our model was validated by a highly significant randomization test, Log-rank test, and simple hazard ratio; the concordance index was 0.59. CONCLUSION: This new PDAC nomogram, based solely on preoperative variables, could be a useful tool to patients and counseling physicians in selecting therapy. This model suggests a new concept of resectability that is meant to reflect the biology of the tumor, thus partially overcoming existing definitions, that are mainly based on tumor anatomic features.

Adjuvant Therapy for Stage III Melanoma Without Immediate Completion Lymph Node Dissection.

INTRODUCTION: For patients with stage III melanoma with occult lymph node metastasis, the use of adjuvant therapy is increasing, and completion lymph node dissection (CLND) is decreasing. We sought to evaluate the use of modern adjuvant therapy and outcomes for patients with stage III melanoma who did not undergo CLND. METHODS: Patients with a positive SLNB from 2015 to 2020 who did not undergo CLND were evaluated retrospectively. Nodal recurrence, recurrence-free survival (RFS), distant metastasis-free survival (DMFS), and melanoma-specific survival were evaluated. RESULTS: Among 90 patients, 56 (62%) received adjuvant therapy and 34 (38%) underwent observation alone. Patients who received adjuvant therapy were younger (mean age: 53 vs. 65, p < 0.001) and had higher overall stage (Stage IIIb/c 75% vs. 54%, p = 0.041). Disease recurred in 12 of 34 patients (35%) in the observation group and 11 of 56 patients (20%) in the adjuvant therapy group. The most common first site of recurrence was distant recurrence alone (5/34 patients) in the observation group and nodal recurrence alone (8/90 patients) in the adjuvant therapy group. Despite more adverse nodal features in the adjuvant therapy group, 24-month nodal recurrence rate and RFS were not significantly different between the adjuvant and observation cohorts (nodal recurrence rate: 26% vs. 20%, p = 0.68; RFS: 75% vs. 61%, p = 0.39). Among patients with stage IIIb/c disease, adjuvant therapy was associated with a significantly improved 24-month DMFS (86% vs. 59%, p = 0.04). CONCLUSIONS: In this early report, modern adjuvant therapy in patients who forego CLND is associated with longer DMFS among patients with stage IIIb/c disease.

De-implementation of Axillary Dissection in Women With Breast Cancer is Largely Driven By Site-level Contextual Effects.

OBJECTIVE: To assess the contribution of unknown institutional factors (contextual effects) in the de-implementation of cALND in women with breast cancer. SUMMARY OF BACKGROUND DATA: Women included in the National Cancer Database with invasive breast carcinoma from 2012 to 2016 that underwent upfront lumpectomy and were found to have a positive sentinel node. METHODS: A multivariable mixed effects logistic regression model with a random intercept for site was used to determine the effect of patient, tumor, and institutional variables on the risk of cALND. Reference effect measureswere used to describe and compare the contribution of contextual effects to the variation in cALND use to that of measured variables. RESULTS: By 2016, cALND was still performed in at least 50% of the patients in a quarter of the institutions. Black race, younger women and those with larger or hormone negative tumors were more likely to undergo cALND. However, the width of the 90% reference effect measures range for the contextual effects exceeded that of the measured site, tumor, time, and patient demographics, suggesting institutional contextual effects were the major drivers of cALND de-implementation. For instance, a woman at an institution with low-risk of performing cALND would have 74% reduced odds of havinga cALND than if she was treated at a median-risk institution, while a patient at a high-risk institution had 3.91 times the odds. CONCLUSION: Compared to known patient, tumor, and institutional factors, contextual effects had a higher contribution to the variation in cALND use.

The GPR171 pathway suppresses T cell activation and limits antitumor immunity.

The recently identified G-protein-coupled receptor GPR171 and its ligand BigLEN are thought to regulate food uptake and anxiety. Though GPR171 is commonly used as a T cell signature gene in transcriptomic studies, its potential role in T cell immunity has not been explored. Here we show that GPR171 is transcribed in T cells and its protein expression is induced upon antigen stimulation. The neuropeptide ligand BigLEN interacts with GPR171 to suppress T cell receptor-mediated signalling pathways and to inhibit T cell proliferation. Loss of GPR171 in T cells leads to hyperactivity to antigen stimulation and GPR171 knockout mice exhibit enhanced antitumor immunity. Blockade of GPR171 signalling by an antagonist promotes antitumor T cell immunity and improves immune checkpoint blockade therapies. Together, our study identifies the GPR171/BigLEN axis as a T cell checkpoint pathway that can be modulated for cancer immunotherapy.

Implementation of Minimally Invasive Pancreaticoduodenectomy at Low and High-Volume Centers.

BACKGROUND: There is a need to better define the safety of implementing the use of minimally invasive pancreaticoduodenectomy (MIPD) in order to provide evidence for safe application. The objective of this study was to evaluate the mortality associated with the implementation of MIPD across low and high-volume facilities using the National Cancer Database (NCDB). METHODS: Patients in the NCDB with pancreatic cancer diagnosed from 2010-2016 undergoing MIPD were selected. Cumulative MIPD volume for each facility was calculated from the number of MIPD cases performed each year prior to and including the year of a patient's operation. A random effects logistic regression model was used to examine the adjusted association between log-transformed cumulative MIPD volume and 90-day mortality. RESULTS: After controlling for patient, tumor and facility-related variables, there was decreased 90-day mortality as the cumulative MIPD volume increased (OR 0.81; 95% CI 0.69-0.95; P = 0.009). Average annual open pancreaticoduodenectomy (PD) volume was independently protective throughout the implementation phase (OR 0.98; 95% CI 0.97-0.99; P = 0.049). This equates to an average predicted probability of 90-day mortality for the first 5 cumulative MIPD cases of 7.51% at a low-volume facility (5 open PDs per year) versus 4.39% at a high-volume facility (50 open PDs per year). CONCLUSIONS: Using the NCDB, 90-day mortality following MIPD decreased with higher cumulative facility MIPD case volume. Although higher cumulative MIPD case volume was associated with reduced 90-day mortality at both low and high-volume facilities, the higher mortality during the implementation of MIPD is magnified at low-volume facilities. This retrospective analysis demonstrates that MIPD can be safely implemented with low mortality at facilities with high-volume open PD programs.

Melanoma Metastases to the Adrenal Gland Are Highly Resistant to Immune Checkpoint Inhibitors.

BACKGROUND: Adrenal gland metastases (AGMs) are common in advanced-stage melanoma, occurring in up to 50% of patients. The introduction of immune checkpoint inhibitors (ICIs) has markedly altered the outcome of patients with melanoma. However, despite significant successes, anecdotal evidence has suggested that treatment responses in AGMs are significantly lower than in other metastatic sites. We sought to investigate whether having an AGM is associated with altered outcomes and whether ICI responses are dampened in the adrenal glands. PATIENTS AND METHODS: We retrospectively compared ICI responses and overall survival (OS) in 68 patients with melanoma who were diagnosed with an AGM and a control group of 100 patients without AGMs at a single institution. Response was determined using RECIST 1.1. OS was calculated from time of ICI initiation, anti-PD-1 initiation, initial melanoma diagnosis, and stage IV disease diagnosis. Tumor-infiltrating immune cells were characterized in 9 resected AGMs using immunohistochemical analysis. RESULTS: Response rates of AGMs were significantly lower compared with other metastatic sites in patients with AGMs (16% vs 22%) and compared with those without AGMs (55%). Patients with AGMs also had significantly lower median OS compared with those without AGMs (3.1 years vs not reached, respectively). We further observed that despite this, AGMs exhibited high levels of tumor-infiltrating immune cells. CONCLUSIONS: In this cohort of patients with melanoma, those diagnosed with an AGM had lower ICI response rates and OS. These results suggest that tissue-specific microenvironments of AGMs present unique challenges that may require novel, adrenal gland-directed therapies or surgical resection.

Pancreatic incidentalomas: Investigation and management.

The incidence of pancreatic incidentalomas (PIs) detected in otherwise asymptomatic patients is growing with the increasing quality and use of advanced imaging techniques. PI can present as isolated main pancreatic duct dilation or as a solid or cystic lesion. Although historically thought to be relatively rare, PIs are rather common, particularly cystic lesions of the pancreas, which can be detected in up to 49% of the general population. With the poor prognosis of pancreatic cancer, PIs are an opportunity for prevention and early diagnosis, but when managed poorly, they can also lead to overtreatment and unnecessary morbidity. The management of PI should begin with a dedicated pancreas protocol computed tomography (CT) scan or magnetic resonance imaging (MRI) to accurately characterize duct size, lesion characteristics and establish an accurate baseline for subsequent follow up. Diagnosis and subsequent management depends on the extent of main duct dilation and solid versus cystic appearance. Solid lesions are highly concerning for malignancy. Cystic lesions can be further categorized as intraductal papillary mucinous neoplasms of the pancreas (IPMNs) or mucinous cystic neoplasms (MCNs), both of which harbour malignant potential, or as serous cystic neoplasms (SCNs) that are benign. In this paper, we summarize the major challenges related to PI and present pragmatic suggestions for management.

Blockade of the CD93 pathway normalizes tumor vasculature to facilitate drug delivery and immunotherapy.

The immature and dysfunctional vascular network within solid tumors poses a substantial obstacle to immunotherapy because it creates a hypoxic tumor microenvironment that actively limits immune cell infiltration. The molecular basis underpinning this vascular dysfunction is not fully understood. Using genome-scale receptor array technology, we showed here that insulin-like growth factor binding protein 7 (IGFBP7) interacts with its receptor CD93, and we subsequently demonstrated that this interaction contributes to abnormal tumor vasculature. Both CD93 and IGFBP7 were up-regulated in tumor-associated endothelial cells. IGFBP7 interacted with CD93 via a domain different from multimerin-2, the known ligand for CD93. In two mouse tumor models, blockade of the CD93/IGFBP7 interaction by monoclonal antibodies promoted vascular maturation to reduce leakage, leading to reduced tumor hypoxia and increased tumor perfusion. CD93 blockade in mice increased drug delivery, resulting in an improved antitumor response to gemcitabine or fluorouracil. Blockade of the CD93 pathway triggered a substantial increase in intratumoral effector T cells, thereby sensitizing mouse tumors to immune checkpoint therapy. Last, analysis of samples from patients with cancer under anti-programmed death 1/programmed death-ligand 1 treatment revealed that overexpression of the IGFBP7/CD93 pathway was associated with poor response to therapy. Thus, our study identified a molecular interaction involved in tumor vascular dysfunction and revealed an approach to promote a favorable tumor microenvironment for therapeutic intervention.

Induction Chemotherapy Plus Neoadjuvant Chemoradiation for Esophageal and Gastroesophageal Junction Adenocarcinoma.

BACKGROUND: Neoadjuvant chemotherapy with concurrent radiotherapy (nCRT) is an accepted treatment regimen for patients with potentially curable esophageal and gastroesophageal junction (GEJ) adenocarcinoma. The purpose of this study is to evaluate whether induction chemotherapy (IC) before nCRT is associated with improved pathologic complete response (pCR) and overall survival (OS) when compared with patients who received nCRT alone for esophageal and GEJ adenocarcinoma. METHODS: Using the National Cancer Database (NCDB), patients who received nCRT and curative-intent esophagectomy for esophageal or GEJ adenocarcinoma from 2006 to 2015 were included. Chemotherapy and radiation therapy start dates were used to define cohorts who received IC before nCRT (IC + nCRT) versus those who only received concurrent nCRT before surgery. Propensity weighting was conducted to balance patient, disease, and facility covariates between groups. RESULTS: 12,460 patients met inclusion criteria, of whom 11,880 (95%) received nCRT and 580 (5%) received IC + nCRT. Following propensity weighting, OS was significantly improved among patients who received IC + nCRT versus nCRT (HR 0.82; 95% CI 0.74-0.92; p < 0.001) with median OS for the IC + nCRT cohort of 3.38 years versus 2.45 years for nCRT. For patients diagnosed from 2013 to 2015, IC + nCRT was also associated with higher odds of pCR compared with nCRT (OR 1.59; 95% CI 1.14-2.21; p = 0.007). CONCLUSION: IC + nCRT was associated with a significant OS benefit as well as higher pCR rate in the more modern patient cohort. These results merit consideration of a sufficiently powered prospective multiinstitutional trial to further evaluate these observed differences.

Impact of neoadjuvant chemotherapy and stereotactic body radiation therapy (SBRT) on R0 resection rate for borderline resectable and locally advanced pancreatic cancer.

BACKGROUND: The role of neoadjuvant stereotactic body radiation therapy (SBRT) in patients with borderline resectable pancreas cancer (BRPC) and locally advanced pancreas cancer (LAPC) remains controversial. METHODS: We retrospectively evaluated BRPC and LAPC patients treated at our institution who underwent 2-3 months of chemotherapy followed by SBRT to a dose of 30-33 Gy. Overall survival (OS) and recurrence-free survival (RFS) were estimated and compared by Kaplan-Meier and log-rank methods. RESULTS: We identified 103 (85 BRPC and 18 LAPC) patients treated per our neoadjuvant paradigm between 2011 and 2018, with resectability based on NCCN definitions. Median follow up was 25 months. Of patients completing neoadjuvant therapy, 73 (71%) underwent definitive resection. Seventy-one (97%) patients with definitively resected tumors had R0 resection and 5 (7%) had a complete pathologic response CR to neoadjuvant therapy. The median overall survival (OS) of the cohort was 24 months. Those with a complete or marked pathologic response had significantly better OS than those with a moderate response (41 vs 24 months, p < 0.02) and patients unable to undergo definitive surgery (17 months, p < 0.0003). Six resected patients experienced grade ≥3 surgical complications. CONCLUSIONS: Neoadjuvant chemotherapy and SBRT are associated with promising pathologic response rates and R0 resection rates, with acceptable perioperative morbidity.

Outcomes After Converted Minimally Invasive to Open Esophagectomy in Patients With Esophageal Cancer.

BACKGROUND: The objective of this study was to evaluate the impact of unplanned conversion to open esophagectomy during minimally invasive esophagectomy (MIE) on postoperative morbidity and mortality for patients with esophageal cancer, as well as to evaluate the variables that influence the need for conversion. METHODS: This study was a retrospective analysis of patients with esophageal cancer who underwent open esophagectomy or MIE by either a laparothoracoscopic approach or a robotic approach from 2016 to 2018 by using the esophagectomy-specific American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database. Poisson regression models were used to analyze 30-day outcomes and risk factors for conversion to open esophagectomy during attempted MIE. RESULTS: A total of 2616 patients were identified. The overall conversion rate for MIE was 6.3%. Compared with completed MIE, patients requiring conversion to open esophagectomy had a significantly increased risk of 30-day mortality (risk ratio, 2.63; 95% confidence interval, 1.03 to 6.69) and experienced a variety of other postoperative complications. Patients requiring conversion to open esophagectomy during MIE also experienced worse perioperative outcomes when compared to patients who underwent planned open esophagectomy. Estimated surgical risk on the basis of the ACS NSQIP Surgical Risk Calculator was the only variable found to be independently associated with conversion from minimally invasive to open esophagectomy (risk ratio, 1.03; 95% confidence interval, 1.01 to 1.04, for each 10% increase in risk score). CONCLUSIONS: Unplanned conversion to open esophagectomy during MIE is associated with significantly greater morbidity and a 2.6-fold increased risk of death when compared with both completed MIE and planned open esophagectomy. The ACS NSQIP Surgical Risk Calculator may help identify patients preoperatively who are at higher risk for conversion to open esophagectomy during MIE.