Tumor FAK orchestrates immunosuppression in ovarian cancer via the CD155/TIGIT axis.

High-grade serous ovarian cancer (HGSOC) is a lethal malignancy characterized by an immunosuppressive tumor microenvironment containing few tumor infiltrating lymphocytes (TILs) and an insensitivity to checkpoint inhibitor immunotherapies. Gains in the PTK2 gene encoding focal adhesion kinase (FAK) at Chr8 q24.3 occur in ∼70% of HGSOC tumors, and elevated FAK messenger RNA (mRNA) levels are associated with poor patient survival. Herein, we show that active FAK, phosphorylated at tyrosine-576 within catalytic domain, is significantly increased in late-stage HGSOC tumors. Active FAK costained with CD155, a checkpoint receptor ligand for TIGIT (T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domains), in HGSOC tumors and a selective association between FAK and TIGIT checkpoint ligands were supported by patient transcriptomic database analysis. HGSOC tumors with high FAK expression were associated with low CD3 mRNA levels. Accordingly, late-stage tumors showed elevated active FAK staining and significantly lower levels of CD3+ TILs. Using the KMF (Kras, Myc, FAK) syngeneic ovarian tumor model containing spontaneous PTK2 (FAK) gene gains, the effects of tumor intrinsic genetic or oral small molecule FAK inhibitior (FAKi; VS-4718) were evaluated in vivo. Blocking FAK activity decreased tumor burden, suppressed ascites KMF-associated CD155 levels, and increased peritoneal TILs. The combination of FAKi with blocking TIGIT antibody (1B4) maintained elevated TIL levels and reduced TIGIT+ T regulatory cell levels, prolonged host survival, increased CXCL13 levels, and led to the formation of omental tertiary lymphoid structures. Collectively, our studies support FAK and TIGIT targeting as a rationale immunotherapy combination for HGSOC.

The impact of the California state lockdown during the COVID-19 pandemic on management of patients with pancreatic ductal adenocarcinoma.

BACKGROUND AND OBJECTIVES: The SARS-COVID-19 pandemic significantly limited healthcare access. We sought to evaluate whether California's lockdown in March 2020 affected staging and time to treatment of pancreatic ductal adenocarcinoma (PDAC). We hypothesized that patients diagnosed after the lockdown would have longer time to treatment and higher stage at presentation. METHODS: We retrospectively identified and categorized 1294 patients presenting to five University of California healthcare systems with a new diagnosis of PDAC into "pre-lockdown" and "post-lockdown" groups based on timing of pathologic diagnosis. RESULTS: In the 12 months pre-lockdown, 835 patients were diagnosed with PDAC, and 459 patients in the 6 months post-lockdown. Demographics, staging, and treatment type were similar between eras. There was a decreased male:female ratio post- versus pre-lockdown (0.97 vs. 1.25; p = 0.03). Time from symptom onset to first treatment was significantly increased among females post-lockdown (p = 0.001). However, overall time from diagnosis to first treatment was shorter in the post-lockdown era (median 23 vs. 26 days, p < 0.001). CONCLUSIONS: The COVID-19 lockdown did not significantly delay initial presentation, diagnosis, or treatment of newly diagnosed PDAC patients. Time from diagnosis to first treatment was shorter post-lockdown. Reduced healthcare utilization for minor complaints and increased telehealth utilization may have contributed.

The Landmark Series: Locally Advanced Pancreatic Cancer and Ablative Therapy Options.

Locally advanced pancreatic cancer (LAPC) is a challenging disease to treat. There is consensus that systemic chemotherapy should be the first line of therapy for most patients. However, there is no consensus on how to manage those patients who do not have sufficient response to become candidates for resection but also do not have distant progression after weeks or months of systemic therapy. Radiation therapy is the most commonly used and best-studied local ablative therapy. One recent randomized controlled trial (LAP-07) failed to demonstrate an overall survival benefit for conventional chemoradiation therapy after induction chemotherapy versus chemotherapy alone. This study had several limitations, and ongoing studies are re-evaluating the role of chemoradiation after more effective chemotherapy regimens as well as more advanced radiation techniques. In parallel, there has been increasing interest in other thermal and non-thermal methods of ablation. In particular, irreversible electroporation has gained traction for treatment of LAPC, with at least one ongoing randomized controlled trial designed to address its role compared with systemic chemotherapy alone. Multiple preclinical and clinical studies are investigating combinations of local ablation and immunotherapy with the goal of generating immune responses that will meaningfully improve outcomes.

Aptamers as Therapeutics.

Aptamers are single-stranded nucleic acid molecules that bind to and inhibit proteins and are commonly produced by systematic evolution of ligands by exponential enrichment (SELEX). Aptamers undergo extensive pharmacological revision, which alters affinity, specificity, and therapeutic half-life, tailoring each drug for a specific clinical need. The first therapeutic aptamer was described 25 years ago. Thus far, one aptamer has been approved for clinical use, and numerous others are in preclinical or clinical development. This review presents a short history of aptamers and SELEX, describes their pharmacological development and optimization, and reviews potential treatment of diseases including visual disorders, thrombosis, and cancer.

Polymer-Mediated Inhibition of Pro-invasive Nucleic Acid DAMPs and Microvesicles Limits Pancreatic Cancer Metastasis.

Nucleic acid binding polymers (NABPs) have been extensively used as vehicles for DNA and RNA delivery. More recently, we discovered that a subset of these NABPs can also serve as anti-inflammatory agents by capturing pro-inflammatory extracellular nucleic acids and associated protein complexes that promote activation of toll-like receptors (TLRs) in diseases such as lupus erythematosus. Nucleic-acid-mediated TLR signaling also facilitates tumor progression and metastasis in several cancers, including pancreatic cancer (PC). In addition, extracellular DNA and RNA circulate on or within lipid microvesicles, such as microparticles or exosomes, which also promote metastasis by inducing pro-tumorigenic signaling in cancer cells and pre-conditioning secondary sites for metastatic establishment. Here, we explore the use of an NABP, the 3rd generation polyamidoamine dendrimer (PAMAM-G3), as an anti-metastatic agent. We show that PAMAM-G3 not only inhibits nucleic-acid-mediated activation of TLRs and invasion of PC tumor cells in vitro, but can also directly bind extracellular microvesicles to neutralize their pro-invasive effects as well. Moreover, we demonstrate that PAMAM-G3 dramatically reduces liver metastases in a syngeneic murine model of PC. Our findings identify a promising therapeutic application of NABPs for combating metastatic disease in PC and potentially other malignancies.

A prospective, multi-institution assessment of irreversible electroporation for treatment of locally advanced pancreatic adenocarcinoma: initial outcomes from the AHPBA pancreatic registry.

BACKGROUND: The optimal treatment and management of locally advanced pancreatic cancer (LAPC) remains unclear and controversial. This study aimed to report the initial outcomes of the AHPBA Registry and evaluate the reproducibility of existing evidence that the addition of Irreversible Electroporation (IRE), a nonthermal ablative treatment, confers survival benefits beyond standard therapeutic options for patients with LAPC. METHODS: From December 2015 to October 2017, patients with LAPC were treated with open-technique IRE following the AHPBA Registry Protocols. Patient demographics, long-term outcomes, and adverse events were recorded. Survival analyses were performed using Kaplan-Meier (KM) curves for overall survival (OS), progression free survival (PFS) and time to progression (TTP). RESULTS: A total of 152 patients underwent successful IRE. Morbidity and mortality were 18% and 2% respectively, with 19 (13%) patients experiencing severe adverse events. Nine (6%) patients presented with local recurrence. Median TTP, PFS, and OS from diagnosis were 27.3 months, 22.8 months, and 30.7 months respectively. CONCLUSION: The combination of IRE with established multiagent therapy is safe and demonstrates encouraging survival among patients with LAPC. IRE is associated with a low rate of serious adverse events and has been optimized for more widespread adoption through the standardized protocols available through the AHPBA registry.

TGF-ß-induced stromal CYR61 promotes resistance to gemcitabine in pancreatic ductal adenocarcinoma through downregulation of the nucleoside transporters hENT1 and hCNT3.

Pancreatic ductal adenocarcinoma (PDAC) is a lethal cancer in part due to inherent resistance to chemotherapy, including the first-line drug gemcitabine. Although low expression of the nucleoside transporters hENT1 and hCNT3 that mediate cellular uptake of gemcitabine has been linked to gemcitabine resistance, the mechanisms regulating their expression in the PDAC tumor microenvironment are largely unknown. Here, we report that the matricellular protein cysteine-rich angiogenic inducer 61 (CYR61) negatively regulates the nucleoside transporters hENT1 and hCNT3. CRISPR/Cas9-mediated knockout of CYR61 increased expression of hENT1 and hCNT3, increased cellular uptake of gemcitabine and sensitized PDAC cells to gemcitabine-induced apoptosis. In PDAC patient samples, expression of hENT1 and hCNT3 negatively correlates with expression of CYR61 . We demonstrate that stromal pancreatic stellate cells (PSCs) are a source of CYR61 within the PDAC tumor microenvironment. Transforming growth factor-ß (TGF-ß) induces the expression of CYR61 in PSCs through canonical TGF-ß-ALK5-Smad2/3 signaling. Activation of TGF-ß signaling or expression of CYR61 in PSCs promotes resistance to gemcitabine in PDAC cells in an in vitro co-culture assay. Our results identify CYR61 as a TGF-ß-induced stromal-derived factor that regulates gemcitabine sensitivity in PDAC and suggest that targeting CYR61 may improve chemotherapy response in PDAC patients.

A standardized care plan is associated with shorter hospital length of stay in patients undergoing pancreaticoduodenectomy.

BACKGROUND: In this retrospective review, we evaluate a standardized care plan (SCP) for patients undergoing pancreaticoduodenectomy, which included selective placement of feeding jejunostomy tubes (FJTs) and a perioperative fast-track recovery pathway (FTRP). METHODS: A review of 242 patients undergoing pancreaticoduodenectomy was completed. Patients treated pre- and post-SCP implementation were compared. Univariate comparison followed by multivariable linear regression were performed to identify predictors of hospital length of stay (HLOS). RESULTS: SCP patients (n = 100) were slightly older but otherwise similar to pre-SCP patients (n = 142). FJT placement occurred less frequently in SCP patients (38 versus 94%, P < 0.001). All SCP patients were initiated on the FTRP. Among SCP patients, an oral diet was introduced earlier (5 versus 8.5 d, P < 0.001) and HLOS was shorter (11 versus 13 d, P = 0.015). Readmission rates were similar. Following adjustment with linear regression, we confirmed SCP status as a predictor of HLOS. To assess SCP components, HLOS was evaluated separately based on FTRP status and FJT placement. Although both were highly associated with HLOS, neither was independently predictive in multivariable analysis. CONCLUSIONS: Implementation of an SCP resulted in shorter HLOS without an increase in readmissions. Future studies are necessary to identify specific components of SCPs that most influence outcomes.

Defining the learning curve for team-based laparoscopic pancreaticoduodenectomy.

BACKGROUND: The purpose of this study was to define the learning curves for laparoscopic pancreaticoduodenectomy (LPD) with and without laparoscopic reconstruction, using paired surgical teams consisting of advanced laparoscopic-trained surgeons and advanced oncologic-trained surgeons. METHODS: All patients undergoing PD without vein resection at a single institution were retrospectively analyzed. LPD was introduced by initially focusing on laparoscopic resection followed by open reconstruction (hybrid) for 18 months prior to attempting a totally LPD (TLPD) approach. Cases were compared with Chi square, Fisher's exact test, and Kruskal-Wallis analysis of variance (ANOVA). RESULTS: Between March 2010 and June 2013, 140 PDs were completed at our institution, of which 56 (40 %) were attempted laparoscopically. In 31/56 procedures we planned to perform only the resection laparoscopically (hybrid), of which 7 (23 %) required premature conversion before completion of resection. Following the first 23 of these hybrid cases, a total of 25 TLPDs have been performed, of which there were no conversions to open. For all LPD, a significant reduction in operative times was identified following the first 10 patients (median 478.5 vs. 430.5 min; p = 0.01), approaching open PD levels. After approximately 50 cases, operative times and estimated blood loss were consistently lower than those for open PD. CONCLUSIONS: In our experience of building an LPD program, the initial ten cases represent the biggest hurdle with respect to operative times. For an experienced teaching center using a staged and team-based approach, LPD appears to offer meaningful reductions in operative time and blood loss within the first 50 cases.

The role of clinical care pathways: an experience with distal pancreatectomy.

BACKGROUND: Previous studies have indicated that clinical pathways may shorten hospital length of stay (HLOS) among patients undergoing distal pancreatectomy (DP). Here, we evaluate an institutional standardized care pathway (SCP) for patients undergoing DP. MATERIALS AND METHODS: A retrospective review of patients undergoing DP from November 2006 to November 2012 was completed. Patients treated before and after implementation of the SCP were compared. Multivariable linear regression was then performed to identify independent predictors of HLOS. RESULTS: There were no differences in patient characteristics between SCP (n=50) and pre-SCP patients (n=100). Laparoscopic technique (62% versus 13%, P<0.001), splenectomy (52% versus 38%, P=0.117), and concomitant major organ resection (24% versus 13%, P=0.106) were more common among SCP patients. Overall, important complication rates were similar (24% versus 26%, P=0.842). SCP patients resumed a normal diet earlier (4 versus 5 d, P=0.025) and had shorter HLOS (6 versus 7 d, P=0.026). There was no increase in 30-d resurgery or readmission. In univariate comparison, SCP, cancer diagnoses, intraductal papillary mucinous neoplasm diagnoses, neoadjuvant therapy, operative technique, major organ resection, and feeding tube placement were associated with HLOS; however, after multivariable adjustment, only laparoscopic technique (-33%, P=0.001), concomitant major organ resection (+38%, P<0.001), and feeding tube placement (+68%, P<0.001) were independent predictors of HLOS. CONCLUSIONS: Implementation of a clinical pathway did not improve HLOS at our institution. The increasing use of laparoscopy likely accounts for shorter HLOS in the SCP cohort. In the future, it will be important to identify clinical scenarios most likely to benefit from implementation of a clinical pathway.

Wound classification reporting in HPB surgery: can a single word change public perception of institutional performance?

INTRODUCTION: The drive to improve outcomes and the inevitability of mandated public reporting necessitate uniform documentation and accurate databases. The reporting of wound classification in patients undergoing hepato-pancreatico-biliary (HPB) surgery and the impact of inconsistencies on quality metrics were investigated. METHODS: The 2005-2011 National Surgical Quality Improvement Program (NSQIP) participant use file was interrogated to identify patients undergoing HPB resections. The effect of wound classification on post-operative surgical site infection (SSI) rates was determined through logistic regression. The impact of variations in wound classification reporting on perceived outcomes was modelled by simulating observed-to-expected (O/E) ratios for SSI. RESULTS: In total, 27,376 patients were identified with significant heterogeneity in wound classification. In spite of clear guidelines prompting at least 'clean-contaminated' designation for HPB resections, 8% of all cases were coded as 'clean'. Contaminated [adjusted odds ratio (AOR): 1.39, P = 0.001] and dirty (AOR: 1.42, P = 0.02] cases were associated with higher odds of SSI, whereas clean-contaminated were not (P = 0.99). O/E ratios were highly sensitive to modest changes in wound classification. CONCLUSIONS: Perceived performance is affected by heterogeneous reporting of wound classification. As institutions work to improve outcomes and prepare for public reporting, it is imperative that all adhere to consistent reporting practices to provide accurate and reproducible outcomes.

Local ablative therapies and the effect on antitumor immune responses in pancreatic cancer - A review.

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease, projected to rank as the second most prevalent cause of cancer-related mortality by 2030. Despite significant progress in advances in surgical techniques and chemotherapy protocols, the overall survival (OS) remains to be less than 10 % for all stages combined. In recent years, local ablative techniques have been introduced and utilized as additional therapeutic approaches for locally advanced pancreatic cancer (LAPC), with promising results with respect to local tumor control and OS. In addition to successful cytoreduction, there is emerging evidence that local ablation induces antitumor immune activity that could prevent or even treat distant metastatic tumors. The enhancement of antitumor immune responses could potentially make ablative therapy a therapeutic option for the treatment of metastatic PDAC. In this review, we summarize current ablative techniques used in the management of LAPC and their impact on systemic immune responses.

Pressure-Enabled Drug Delivery (PEDD) of a class C TLR9 agonist in combination with checkpoint inhibitor therapy in a murine pancreatic cancer model.

BACKGROUND: Systemic immunotherapy has had limited clinical benefit in pancreatic ductal adenocarcinoma. This is thought to be due to its desmoplastic immunosuppressive tumor microenvironment in addition to high intratumoral pressures that limit drug delivery. Recent preclinical cancer models and early-phase clinical trials have demonstrated the potential of toll-like receptor 9 agonists, including the synthetic CpG oligonucleotide SD-101, to stimulate a wide range of immune cells and eliminate suppressive myeloid cells. We hypothesized that Pressure-Enabled Drug Delivery via Pancreatic Retrograde Venous Infusion of toll-like receptor 9 agonist would improve responsiveness to systemic anti-programmed death receptor-1 checkpoint inhibitor therapy in a murine orthotopic pancreatic ductal adenocarcinoma model. METHODS: Murine pancreatic ductal adenocarcinoma (KPC4580P) tumors were implanted into the pancreatic tails of C57BL/6J mice and treated 8 days after implantation. Mice were assigned to one of the following treatment groups: Pancreatic Retrograde Venous Infusion delivery of saline, Pancreatic Retrograde Venous Infusion delivery of toll-like receptor 9 agonist, systemic anti-programmed death receptor-1, systemic toll-like receptor 9 agonist, or the combination of Pancreatic Retrograde Venous Infusion delivery of toll-like receptor 9 agonist and systemic anti-programmed death receptor-1 (Combo). Fluorescently labeled toll-like receptor 9 agonist (radiant efficiency) was used to measure uptake of the drug on day 1. Changes in tumor burden were evaluated by necropsy at 2 different time points, 7 and 10 days after toll-like receptor 9 agonist treatment. Blood and tumors were collected at necropsy 10 days after toll-like receptor 9 agonist treatment for flow cytometric analysis of tumor-infiltrating leukocytes and plasma cytokines. RESULTS: All mice analyzed survived to necropsy. Site of tumor fluorescence measurements revealed 3-fold higher intensity fluorescence in Pancreatic Retrograde Venous Infusion delivery of toll-like receptor 9 agonist compared to systemic toll-like receptor 9 agonist mice. Tumor weights were significantly lower in the Combo group compared to Pancreatic Retrograde Venous Infusion delivery of saline. Flow cytometry of the Combo group demonstrated significantly increased overall T-cell number, specifically CD4+ T-cells, and a trend toward increased CD8+ T-cells. Cytokine analysis showed significantly decreased IL-6 and CXCL1. CONCLUSION: Pressure-Enabled Drug Delivery of toll-like receptor 9 agonist by Pancreatic Retrograde Venous Infusion with systemic anti-programmed death receptor-1 demonstrated improved pancreatic ductal adenocarcinoma tumor control in a murine pancreatic ductal adenocarcinoma model. These results support study of this combination therapy in pancreatic ductal adenocarcinoma patients and expansion of ongoing Pressure-Enabled Drug Delivery clinical trials.

Treatment of pancreatic cancer with irreversible electroporation and intratumoral CD40 antibody stimulates systemic immune responses that inhibit liver metastasis in an orthotopic model.

BACKGROUND: Pancreatic cancer (PC) has a poor prognosis, and most patients present with either locally advanced or distant metastatic disease. Irreversible electroporation (IRE) is a non-thermal method of ablation used clinically in locally advanced PC, but most patients eventually develop distant recurrence. We have previously shown that IRE alone is capable of generating protective, neoantigen-specific immunity. Here, we aim to generate meaningful therapeutic immune effects by combining IRE with local (intratumoral) delivery of a CD40 agonistic antibody (CD40Ab). METHODS: KPC46 organoids were generated from a tumor-bearing male KrasLSL-G12D-p53LSL-R172H-Pdx-1-Cre (KPC) mouse. Orthotopic tumors were established in the pancreatic tail of B6/129 F1J mice via laparotomy. Mice were randomized to treatment with either sham laparotomy, IRE alone, CD40Ab alone, or IRE followed immediately by CD40Ab injection. Metastatic disease and immune infiltration in the liver were analyzed 14 days postprocedure using flow cytometry and multiplex immunofluorescence imaging with spatial analysis. Candidate neoantigens were identified by mutanome profiling of tumor tissue for ex vivo functional analyses. RESULTS: The combination of IRE+CD40 Ab improved median survival to greater than 35 days, significantly longer than IRE (21 days) or CD40Ab (24 days) alone (p<0.01). CD40Ab decreased metastatic disease burden, with less disease in the combination group than in the sham group or IRE alone. Immunohistochemistry of liver metastases revealed a more than twofold higher infiltration of CD8+T cells in the IRE+CD40 Ab group than in any other group (p<0.01). Multiplex immunofluorescence imaging revealed a 4-6 fold increase in the density of CD80+CD11c+ activated dendritic cells (p<0.05), which were spatially distributed throughout the tumor unlike the sham group, where they were restricted to the periphery. In contrast, CD4+FoxP3+ T-regulatory cells (p<0.05) and Ly6G+myeloid derived cells (p<0.01) were reduced and restricted to the tumor periphery in the IRE+CD40 Ab group. T-cells from the IRE+CD40 Ab group recognized significantly more peptides representing candidate neoantigens than did T-cells from the IRE or untreated control groups. CONCLUSIONS: IRE can induce local tumor regression and neoantigen-specific immune responses. Addition of CD40Ab to IRE improved dendritic cell activation and neoantigen recognition, while generating a strong systemic antitumor T-cell response that inhibited metastatic disease progression.

The impact of vascular resection on early postoperative outcomes after pancreaticoduodenectomy: an analysis of the American College of Surgeons National Surgical Quality Improvement Program database.

BACKGROUND: Several single-center reports suggest that vascular resection (VR) during pancreaticoduodenectomy (PD) for patients with pancreatic adenocarcinoma is feasible without affecting early postoperative mortality or morbidity. Our objective is to review the outcomes associated with VR during PD using a large multicenter data source. METHODS: A retrospective cohort analysis was performed using the National Surgical Quality Improvement Program Participant User Files for 2005-2009. All patients undergoing PD for a postoperative diagnosis of malignant neoplasm of the pancreas were included. Forward stepwise multivariate regression analysis was used to determine the association between VR during PD and 30-day postoperative mortality and morbidity after adjustment for patient demographics and comorbidities. RESULTS: 3,582 patients were included for analysis, 281 (7.8 %) of whom underwent VR during PD. VR during PD was associated with significantly greater risk-adjusted 30-day postoperative mortality [5.7 % with VR versus 2.9 % without VR, adjusted odds ratio (AOR) 2.1, 95 % confidence interval (CI) 1.22-3.73, P = 0.008] and overall morbidity (39.9 % with VR versus 33.3 % without VR, AOR 1.36, 95 % CI 1.05-1.75, P = 0.02). There was no significant difference in risk-adjusted postoperative mortality or morbidity between those patients undergoing VR by the primary surgical team versus those patients undergoing VR by a vascular surgical team. CONCLUSIONS: Contrary to the findings of several previously published single-center analyses, the current study demonstrates increased 30-day postoperative morbidity and mortality in PD with VR when compared with PD alone.

A decision model of therapy for potentially resectable pancreatic cancer.

BACKGROUND: Optimal treatment for potentially resectable pancreatic cancer is controversial. Resection is considered the only curative treatment, but neoadjuvant chemoradiotherapy may offer significant advantages. MATERIALS AND METHODS: We developed a decision model for potentially resectable pancreatic cancer. Initial therapeutic choices were surgery, neoadjuvant chemoradiotherapy, or no treatment; subsequent decisions offered a second intervention if not prohibited by complications or death. Payoffs were calculated as the median expected survival. We gathered evidence for this model through a comprehensive MEDLINE search. One-way sensitivity analyses were performed. RESULTS: Neoadjuvant chemoradiation is favored over initial surgery, with expected values of 18.6 and 17.7 mo, respectively. The decision is sensitive to the probabilities of treatment mortality and tumor resectability. Threshold probabilities are 7.0% mortality of neoadjuvant chemoradiotherapy, 69.2% resectability on imaging after neoadjuvant therapy, and 73.7% resectability at exploration after neoadjuvant therapy, 92.2% resectability at initial resection, and 9.9% surgical mortality following chemoradiotherapy. The decision is sensitive to the utility of time spent in chemoradiotherapy, with surgery favored for utilities less than 0.3 and -0.8, for uncomplicated and complicated chemoradiotherapy, respectively. CONCLUSIONS: The ideal treatment for potentially resectable pancreatic cancer remains controversial, but recent evidence supports a slight benefit for neoadjuvant therapy. Our model shows that the decision is sensitive to the probability of tumor resectability and chemoradiation mortality, but not to rates of other treatment complications. With minimal benefit of one treatment over another based on survival alone, patient preferences will likely play an important role in determining best treatment.

Does preoperative therapy optimize outcomes in patients with resectable pancreatic cancer?

The objective of this study was to compare survival between all patients with radiographically resectable adenocarcinoma of the proximal pancreas who underwent preoperative chemoradiation therapy (PRE-OP CRT) or surgical exploration first (SURGERY) with "intention to resect." Pancreatic cancer patients who undergo resection after PREOP CRT live longer than patients who undergo resection without PREOP CRT, a difference that may be attributable to patient selection. We retrospectively identified 236 patients with pancreatic head adenocarcinoma seen between 1999 and 2007 with sufficient data to be confirmed medically and radiographically resectable. The outcomes of 144 patients who underwent PREOP CRT were compared to those of 92 patients who proceeded straight to SURGERY. The groups were similar in age and gender. Tumors were slightly larger in the PREOP CRT group (mean 2.5 cm vs. 2.1 cm, P < 0.01), and there were trends toward more venous abutment (54% vs. 39%, P = 0.06) and a higher Charlson comorbidity index (P = 0.1). In the PREOP CRT group, 76 patients (53%) underwent resection, 28 (19%) had metastatic and 17 (12%) locally unresectable disease after PREOP CRT, and 23 (16%) were not explored due to performance status or loss to follow-up. In the SURGERY group, 68 patients (74%) underwent resection. Sixteen patients (17%) had metastatic and eight patients (9%) locally unresectable disease at exploration. In patients who underwent resection, the PREOP CRT group had smaller pathologic tumor size and lower incidence of positive lymph nodes than the SURGERY group but no difference in positive margins or need for vascular resection. Median overall survival (OS) in patients undergoing resection was 27 months in the PREOP CRT group and 17 months in the SURGERY group (P = 0.04). Median OS in all patients treated with PREOP CRT or surgically explored with intention to resect was 15 and 13 months, respectively, with superimposable survival curves. Despite a lower resection rate, the PREOP CRT group as a whole had a similar OS to the SURGERY group as a whole. For patients who underwent resection, those in the PREOP CRT had longer survival than those in the SURGERY group, suggesting that PREOP CRT allows better patient selection for resection. PREOP CRT should be considered an acceptable alternative for most patients with resectable pancreatic cancer.

Vascular surgery collaboration during pancreaticoduodenectomy with vascular reconstruction.

BACKGROUND: Once thought to have unresectable disease, pancreatic cancer patients with portal venous involvement are now reported to have comparable survival after pancreaticoduodenectomy (PD) with vascular reconstruction (VR) as compared with patients without vascular involvement. We hypothesize that a multidisciplinary approach involving a vascular surgeon will minimize morbidity and improve patency of VRs. METHODS: We identified 204 patients who underwent PD for pancreatic adenocarcinoma from 1997 to 2008. Patients who underwent PD with VR (N = 42) were compared with those who underwent standard PD (N = 162). VRs were performed by a vascular surgeon and involved primary repair (N = 8), vein patch (N = 25), or interposition grafting (N = 9) with femoral or other venous conduit. RESULTS: Patients undergoing PD with VR had larger tumors (3.0 cm vs. 2.5 cm, P < 0.01) but did not have different rates of tumor-free margins (73% vs. 72%, P = 0.84) or lymph nodes metastases (50% vs. 38%, P = 0.14). The VR group had higher median blood loss (875 mL vs. 550 mL, P = 0<0.01), but no differences in mortality, complication rates, length of stay, or readmission rates were found in a median follow-up of 29 months. Overall survival rates were similar. Predictors of mortality on multivariate analysis included increasing histological grade (P = 0.01), positive lymph nodes (P = 0.01), and increasing tumor size (P = 0.01), but not VR (P = 0.28). When evaluated by computed tomography scans within 6 months postoperatively, 97% of reconstructions remained patent. CONCLUSIONS: The need for VR is not a contraindication to potentially curative resection in patients with pancreatic adenocarcinoma. Assistance of a vascular surgeon during VR may allow moderate-volume centers to achieve outcomes comparable with high-volume centers.

Notch promotes radioresistance of glioma stem cells.

Radiotherapy represents the most effective nonsurgical treatments for gliomas. However, gliomas are highly radioresistant and recurrence is nearly universal. Results from our laboratory and other groups suggest that cancer stem cells contribute to radioresistance in gliomas and breast cancers. The Notch pathway is critically implicated in stem cell fate determination and cancer. In this study, we show that inhibition of Notch pathway with gamma-secretase inhibitors (GSIs) renders the glioma stem cells more sensitive to radiation at clinically relevant doses. GSIs enhance radiation-induced cell death and impair clonogenic survival of glioma stem cells but not non-stem glioma cells. Expression of the constitutively active intracellular domains of Notch1 or Notch2 protect glioma stem cells against radiation. Notch inhibition with GSIs does not alter the DNA damage response of glioma stem cells after radiation but rather reduces Akt activity and Mcl-1 levels. Finally, knockdown of Notch1 or Notch2 sensitizes glioma stem cells to radiation and impairs xenograft tumor formation. Taken together, our results suggest a critical role of Notch signaling to regulate radioresistance of glioma stem cells. Inhibition of Notch signaling holds promise to improve the efficiency of current radiotherapy in glioma treatment.