Resected PDAC Research Articles

Abstract B48: Targeting the semaphorin 4D-plexin B axis to augment FOLFIRINOX in a murine model of pancreatic adenocarcinoma

Abstract Background: Pancreatic adenocarcinoma (PDAC) is the fourth leading cause of cancer-related mortality, with dismal 5-year prognosis of 8%, in part due to poor response to available therapies. Thus, new systemic cancer control therapies are in dire need. Semaphorin 4D (SEMA4D) is a soluble and membrane bound glycoprotein that binds its cognate Plexin B1/B2 receptors, expressed on monocytic and granulocytic leukocytes. Prior work has shown that increased expression of SEMA4D and Plexin B in resected PDAC patients is associated with lymph node and distant metastasis, as well as a worse prognosis. Additionally, SEMA4D blockade has conferred improved immune checkpoint blockade response in murine models of colorectal carcinoma and head and neck squamous cell carcinoma via abrogation of myeloid-derived suppressor cell recruitment and function, as well as enhanced T-cell recruitment and activity within the tumor microenvironment. Here we study the effects of SEMA4D blockade in a murine model of PDAC. Methods: C57b/6 mice were orthotopically injected with murine PDAC line (KP2) derived from KRASG12D,TP53Flox/Wt;P48-Cre autochthonous tumors. Mice were treated with Folfirinox (5-FU, irinotecan, oxaliplatin, weekly), immune checkpoint blockade (ICB) (anti-PD1, anti-CTLA-4 mAbs bi-weekly), and anti-SEMA4D mAB (biweekly). Peripheral blood and tumor-infiltrating leukocytes from patients with PDAC undergoing pancreaticoduodenectomy were assessed for Plexin B1 via flow cytometry. Results: Human PDAC demonstrates penetration of Plexin B1 positive leukocytes, most notably tumor-associated macrophages, neutrophils, and monocytes. Mice injected with KP2 developed tumors detectable via high-frequency ultrasound and exhibited longer survival when treated with the combination of Folfirinox, ICB, and anti-SEMA4D antibody, compared to Folfirinox alone, Folfirinox plus ICB, or Folfirinox plus anti-SEMA4D antibody. Conclusions: Plexin B1+ myeloid subsets penetrate human PDAC tumors, and treatment with SEMA4D-blocking antibody improved response to ICB in combination with standard-of-care Folfirinox in preclinical murine studies. Future work will focus on understanding the immune mechanism of improved therapeutic response, as well as further characterization of the prevalence and prognostic ramifications of the SEMA4D-Plexin B axis in PDAC. Citation Format: Luis I. Ruffolo, Katherine M. Jackson, Nicholas Ullman, Alexander Chacon, Alexa Melucci, Paul Burchard, Mary Georger, Rachel Jewell, Peter Prieto, Brian Belt, Crystal Mallow, Elizabeth Evans, Terrence Fisher, Maurice Zauderer, Christina Wu, Brian Olson, Gregory B. Lesinski, David C. Linehan. Targeting the semaphorin 4D-plexin B axis to augment FOLFIRINOX in a murine model of pancreatic adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr B48.

Oncologic Outcomes After Robotic Pancreatic Resections Are Not Inferior to Open Surgery.

Compare oncologic outcomes after open and robotic pancreatic resections for pancreatic adenocarcinoma (PDAC). Receipt of adjuvant chemotherapy improves survival after resected PDAC. Complications after pancreatectomy have been shown to prohibit the administration of adjuvant chemotherapy and survival. We examined the effect of surgical approach on receipt of adjuvant chemotherapy, complications, and overall survival after pancreatectomy. A single-institution retrospective review of all patients with PDAC who underwent robotic or open pancreatectomy from 2011 to 2016 with 24-month follow-up. Four hundred fifty-six patients underwent resection: 226 robotic and 230 open. No significant difference was identified in major complications or receipt of adjuvant chemotherapy between robotic and open pancreatectomy, nor was approach an independent predictor of these outcomes. Robotic pancreatectomy patients had a shorter length of stay than patients who underwent open pancreatectomy (7 days vs 9 days; P < 0.001). Additionally, wound infection rate (32.3% vs 12.4%, P < 0.0001) and transfusion (39.6% vs 12.4%, P < 0.0001) was improved in robotic pancreatectomy group with no differences in perioperative mortality. Improved median overall survival approached statistical significance for the robotic cohort (25.6 months vs 23.9 months; P = 0.055); however, on multivariable analysis the robotic approach predicted overall survival, (hazard ratio 0.77, P = 0.041). Robotic approach was an independent predictor of decreased blood loss and less transfusions than the open approach. Robotic pancreatectomy was not inferior compared to open pancreatectomy in a high-volume experienced center for oncologic outcomes and due to decreased blood loss and transfusion may have improved survival.

Stromal fibronectin expression in patients with resected pancreatic ductal adenocarcinoma

BackgroundPancreatic ductal adenocarcinoma (PDAC) is characterized by an extremely dense stroma, which has a fundamental role in tumor progression. Fibronectin (FN1) is the main constituent of the tumor stroma in pancreatic cancer. This study aimed to explore the association between FN1 and clinicopathological characteristics and disease survival.MethodsFormalin-fixed paraffin-embedded tissue samples from 138 patients with PDAC were constructed into a tissue microarray, followed by immunohistochemical analysis with a recombinant monoclonal FN1 antibody. Chi-square test or Fisher’s exact test were used for comparison of FN1 expression and relevant clinicopathological parameters. Kaplan-Meier survival curves and Cox regression analyses were used to assess the association between FN1 and survival.ResultsFN1 was detected in the stromal compartment in most cases (117/138, 84.8%). Compared to the low FN1 expression group, the high FN1 expression group had significantly larger tumor size (P = 0.002), more advanced T stage (P = 0.039) and N stage (P = 0.009), and also worse AJCC stage (P = 0.003). However, stromal FN1 expression was not associated with disease-free survival or overall survival.ConclusionsThis study suggests that high stromal FN1 expression is associated with aggressive tumor characteristics in patients with resected PDAC. However, no association between FN1 expression and survival was found.

Phase II trial of preoperative modified FOLFIRINOX (mFOLFIRINOX) followed by postoperative gemcitabine (GEM) in patients (pts) with borderline resectable pancreatic ductal adenocarcinomas (BR-PDAC).

342 Background: mFOLFIRINOX and GEM are standard chemotherapy for metastatic and resected PDAC, respectively. This phase 2 trial assessed the efficacy and safety of perioperative chemotherapy consisted of preoperative mFOLFIRINOX and postoperative GEM in pts with BR-PDAC. Methods: Pts with histologically proven and radiologically confirmed BR-PDAC as defined by NCCN criteria were eligible. Pts received 8 cycles of preoperative mFOLFIRINOX (oxaliplatin 85 mg/m2, irinotecan 180 mg/m2, 5-FU 2,400 mg/m2 over 46 hours, and leucovorin 400 mg/m2), every 2 weeks. For pts who underwent surgery, postoperative GEM (1,000 mg/m2 D1, 8, 15, every 4 weeks) was given for 6 cycles. Primary endpoint was 1-year progression-free survival (PFS) rate and secondary endpoints were PFS, overall survival (OS) and curative surgery rate. A total of 44 pts were required to show the improvement in 1-year PFS rates from 30% to 50% with a two-sided alpha of 0.05, beta of 0.8 and drop-out rates of 10%. Results: Between May/2016 and Mar/2018, 44 patients were enrolled. Median age was 60 years (range, 35-76) and 26 pts (59%) were male. Pancreas head was most common site (n = 26, 59%). With mFOLFIRINOX, response rate was 34% and surgery was done in 27 patients (61%); 22 and 5 patients achieved R0 and R1 resection, respectively, and postoperative GEM was given in 24 patients (89%). With median follow-up of 16.6 months (95% CI, 10.9-22.2), 1-year PFS rate was 51.7% (95% CI, 35.2-68.2), and median PFS and OS was 13.0 months (95% CI, 7.7-18.4), and 14.3 months (95% CI, not available), respectively. PFS and OS were significantly differed according to the surgery (p &lt; 0.001 for both) and response to mFOLFIRINOX (p &lt; 0.001 and p = 0.03, respectively). Relative dose intensities of irinotecan, oxaliplatin and 5-FU were &gt; 77% during mFOLFIRINOX. Grade 3-4 neutropenia (55%), anemia (14%), nausea (11%), and diarrhea (7%) were most common severe toxicities and 3 pts (7%) discontinued mFOLFIRINOX due to the toxicities. Conclusions: Perioperative chemotherapy using mFOLFIRINOX and GEM were feasible and effective for pts with BR-PDAC. Future randomized trial is warranted. Clinical trial information: NCT02749136.

Correlation between appearance of the retroportal fat plane at preoperative CT and pathology findings in resected adenocarcinoma of the pancreatic head

To correlate the appearance of the retroportal fat plane at preoperative computed tomography (CT) and the pathology findings in resected adenocarcinoma of the pancreatic head (PDAC). Forty-eight patients with resected PDAC of the pancreatic head were included (24 men, 24 women, mean age 63 years, median BMI 24.1). All patients underwent CT <30 days before surgery. The state of the retroperitoneal resection margin and the presence of lymphatic or perineural invasion were obtained from pathology reports. CT images were reviewed independently by two radiologists for assessment of the retroportal fat plane and graded in two categories (clear/effaced). Inter-reader discrepancies were solved in consensus. Interobserver agreement was calculated and Fisher's test was used to assess the correlation between CT and pathology findings. Visceral fat areas were measured and correlated with CT findings. A clear retroportal fat plane was significantly associated with a negative retroperitoneal margin at pathology with 100% specificity and PPV (p=0.0001). No association was observed between the appearance of the fat plane at CT and the presence of lymphatic or perineural invasion (p=ns). Interobserver agreement for retroportal fat plane evaluation was good (0.741). False-positive cases had a significantly lower visceral fat area than the correctly classified patients (p=0.0480). A clear retroportal fat plane is significantly associated with negative retroperitoneal resection margins at pathology. The lack of visceral adipose tissue can lead to overestimation of retroportal fat plane involvement at preoperative CT.

Clinical impact of nonselective beta-blockers on survival in patients with pancreatic cancer- revival of well known drugs?

Background: In preclinical animal studies it has been shown that l stress stimulates PDAC growth and increases catecholamines, VEGF and NGF. Here the impact of beta-blockers in resected PDAC patients was investigated. Methods: PDAC patients from two European centers between 2002 and 2012 (n=595) were studied. 159 patients received beta-blockers (BB). 17 patients with non-selective BB (NSBB) were compared to 85 receiving no BB (NBB) using a matched-pair analysis. 142 patients with beta1 selective agents (SB1B) were also analyzed. Univariate and multivariate survival analysis (Cox) was performed. Organoids from PDAC specimen were treated with B1SB, B2SB, NSBB and GEM. Results: Median age of patients was 70 y (22-88 y). Patients with any BB, had median OS of 25 mo vs. 21 mo with NBB (p=0.0084). Median OS of NSBB was 40 mo vs. 23 mo for NBB (p=0.0007) and 21 mo for SB1B (p=0.0396). Hypertension (HPT) was associated with lower OS compared to no HPT. Even among patients with HPT, a longer median OS was observed among NSBB compared to NBB (40 vs 19 mo; p=0.041). Organoids showed fewer RLU when treated with NSBB or SB2B in addition to GEM comapred to GEM alone (p=0.032). SB1B did not reveal any difference. Conclusion: For the first time a matched pair analysis comparing NSBB to SB1B and NBB in PDAC patients is presented. NSBB almost doubled the OS in PDAC patients in an adjuvant setting. SB1B did show little differences regarding OS. Taken together, targeting the adrenergic beta2-pathway might be a therapeutic strategy.

Safety and efficacy of perioperative chemoradiotherapy of resectable pancreatic cancer

Background: A novel treatment method involving neoadjuvant chemoembolization of tumor vessels prior to intraoperative radiotherapy followed by adjuvant chemotherapy was established for patients with resectable pancreatic cancer. The aim of the present study was to assess the safety and efficacy of this novel treatment scheme. Methods: Records of 114 patients with PDAC treated in Botkin Hospital between 2013-2016 were reviewed. In 28 cases a combination of neoadjuvant chemoembolization (NACE) and pancratic resection was used. 33 patients underwent complex treatment (IORT and pancreatic resection). In 23 cases perioperative chemoradiotherapy (PeriCRT), a novel method, was used. 30 patients were treated by a standard scheme (pancreatic resection and adjuvant chemotherapy). Afterward a histological examination and electron microscopy of irradiated resection margin were performed. Results: All 114 patients underwent gross total resection. By the end of the study only patients in the control group had local reccurence (3/30). The estimated median survival was 336, 356, 359 and 333 days. Long-term survival was 78,6% (NACE), 87,9% (IORT), 95,7% (PeriCRT), 73,3% (control) for one-year survival, respectively (P=0,0257, 95% Cl). All treatment methods were well tolerated by all patients, with few adverse effects and no serious complications. Conclusion: Excellent local control and one-year OS for resected PDAC was achieved by using novel PeriCRT treatment method.

Safety and efficacy of perioperative chemoradiotherapy of resectable pancreatic cancer.

Background: A novel treatment method involving neoadjuvant chemoembolization of tumor vessels prior to intraoperative radiotherapy followed by adjuvant chemotherapy was established for patients with resectable pancreatic cancer. The aim of the present study was to assess the safety and efficacy of this novel treatment scheme. Methods: Records of 114 patients with PDAC treated in Botkin Hospital between 2013-2016 were reviewed. In 28 cases a combination of neoadjuvant chemoembolization (NACE) and pancratic resection was used. 33 patients underwent complex treatment (IORT and pancreatic resection). In 23 cases perioperative chemoradiotherapy (PeriCRT), a novel method, was used. 30 patients were treated by a standard scheme (pancreatic resection and adjuvant chemotherapy). Afterward a histological examination and electron microscopy of irradiated resection margin were performed. Results: All 114 patients underwent gross total resection. By the end of the study only patients in the control group had local reccurence (3/30). The estimated median survival was 336, 356, 359 and 333 days. Long-term survival was 78,6% (NACE), 87,9% (IORT), 95,7% (PeriCRT), 73,3% (control) for one-year survival, respectively (P=0,0257, 95% Cl). All treatment methods were well tolerated by all patients, with few adverse effects and no serious complications. Conclusion: Excellent local control and one-year OS for resected PDAC was achieved by using novel PeriCRT treatment method.

Contemporary analysis of complications associated with biliary stents during neoadjuvant therapy for pancreatic adenocarcinoma

BackgroundWith the increasing use of biliary stents for neoadjuvant therapy (NT) for pancreatic adenocarcinoma (PDAC), the risk of post-pancreaticoduodenectomy (PD) infection remains relevant. This study documents the contemporary incidence of stent-related complications (SRC) during NT and to analyze their impact on surgical infections. MethodsConsecutive patients from a single institution (2011–15) with resected PDAC treated with biliary decompression, NT, and PD were analyzed. Stent-related complications (SRC) were compared among patients with/without prospectively documented composite pre- and post-operative infections (surgical site infection [SSI], organ space infection [OSI], and cholangitis). ResultsOf 114 total patients, (median 164 days, initial stent to surgery), 95% had initial endoscopic (vs. percutaneous) stenting. Initial stents were often plastic (80/114, 70%), with 43/114 (38%) undergoing routine exchange to metal stent before NT. Fifteen (13%) patients had stent cholangitis during NT requiring antibiotics and/or stent exchange. There were 33/114 (29%) patients with SRC, requiring 66 exchanges. Post-PD rates of SSI, OSI, and cholangitis were 23%, 5%, and 4%, respectively [composite rate 30%]. On multivariate analysis, SRC were not associated with composite surgical infections (p > 0.05). ConclusionsAlthough SRC occurred in almost one-third of PDAC patients during NT, with appropriate intervention, there was no association with increased surgical infections.

Association Between Very Small Tumor Size and Decreased Overall Survival in Node-Positive Pancreatic Cancer

In pancreatic adenocarcinoma (PDAC), increasing tumor size usually correlates with a worse prognosis. However, patients with a very small primary tumor who experience lymph node involvement may have a different disease biology. This study sought to determine the interaction between tumor size and lymph node involvement in terms of overall survival (OS). The study identified 17,073 patients with a diagnosis of M0 resected PDAC between 1983 and 2013 using the Surveillance, Epidemiology, and End Results database. The patients were stratified by lymph node involvement (N0 vs N+) and T stage (T1a-T1b vs T1c vs T2 vs T3 vs T4). The Kaplan-Meier method was used to estimate OS, and Cox regression analysis was used to compare survival between subgroups after adjustment for patient-specific factors. Lymph node involvement and T stage significantly interacted (p < 0.001). Among the patients with node-negative disease, 5-year OS decreased monotonically with increasing T stage (59.1%, 30.6%, 22.9%, 16.6%, and 8.0%, respectively; p < 0.001). In contrast, among the patients with node-positive disease, those with T1a-T1b tumors (< 10mm) had worse 5-year OS than those with T1c tumors (7.4% vs 17.6%; adjusted hazard ratio, 0.70; 95% confidence interval, 0.50-0.97; p = 0.034) and similar survival compared with those who had T2, T3, or T4 tumors (9.7%, 8.2%, and 4.8%, respectively; p > 0.2 in all cases). Among patients with lymph node-positive PDAC, very small primary tumors are associated with decreased OS. This finding raises the possibility that small tumors capable of lymph node metastasis might represent more biologically aggressive cancers.

Combination of perioperative chemotherapy and intraoperative radiotherapy for the treatment of resectable pancreatic head cancer

Introduction: A new treatment method involving neoadjuvant chemoembolization of tumor vessels 5 days prior to surgery combined with intraoperative radiotherapy (IORT) followed by adjuvant chemotherapy was established for patients with resectable pancreatic cancer. The aim of the present study was to assess the safety and efficacy of this treatment scheme. Method: Records of 161 patients with resectable PDAC treated in Botkin Hospital between 2013–2017 were reviewed. In 49 cases was used perioperative chemoradiotherapy (PeriCRT). IORT was performed using Carl Zeiss Intrabeam PRS 500 system. After resection stage, a single dose of 20 Gy IORT boost was delivered using 50-kV x-rays to a depth of 1 mm from the applicator surface. Afterward a histological examination and electron microscopy of irradiated resection margin were performed. Results: All 161 patients with PDAC underwent gross total resection (R0) with lymphadenectomy D2. The estimated median survival was 338, 358, 372 and 337 days. Long-term survival was 70,2% (NACE), 75,1% (IORT), 80,7% (PeriCRT), 61,3% (control) for 3-year survival, respectively (p < 0,05, 95% Cl). All treatment methods were well tolerated by all patients, with few adverse effects and no serious complications. There was no association between outcomes, variations in tumor characteristics, marker concentrations and therapeutic response. Conclusions: Good 3-year OS for resected PDAC was achieved by using novel PeriCRT treatment method.

PO-277 Single-cell RNA-seq analysis of human pancreatic ductal adenocarcinoma

IntroductionPancreatic Ductal Adenomcarcinoma (PDAC) is one of the most lethal forms of cancer with a five-year survival rate of 8%. Genetic alterations such as activating mutations in KRAS and inactivating mutations in CDKN2A and TP53, accompanied with changes in surrounding stroma, are involved in progression of pancreatic cancer. However, since these alterations are not well understood at the single cell level, we have been performing single-cell RNA-sequencing (scRNA-seq) analysis of PDAC.Material and methodsWe performed scRNA-seq and histological analysis of a resected human PDAC tumour specimen using the 10X platform and single cell cDNA library construction kit followed by sequencing on a HiSeq4000 (3,640 cells; over 10^5 reads per cell). Bioinformatic analysis included both standard pipelines and custom analysis of TCGA PDAC signatures as first described in (Raphael BJ, 2017; Cancer Cell 32, 2185).Results and discussionsNine distinct cell types were identified by K-means clustering and differential expression analysis. In agreement with histological evidence, slightly less than 10% of the cells were actual ductal carcinoma cells, and the rest were either normal epithelial cells or stromal cells. The TCGA signature identified these ductal carcinoma cells as belonging to the basal subtype of PDAC. Individual clusters included normal pancreatic islet cells, B-lymphocytes, macrophages, mast cells, cells that resemble schwann cells, cancer-associated fibroblasts (CAFs), and normal fibroblasts. Bioinformatic analysis suggested two subtypes of CAFs with different functions: extracellular matrix production, and immunomodulatory, in agreement with a prior report (Ohlund D, Journal of Experimental Medicine, 2017;214(3):579). Histological analysis confirmed presence of the major cell types. Additionally, an epithelial-like cell cluster was observed and further histological analysis is underway to confirm the identity of the same.Conclusion sc-RNAseq of a resected tumour specimen from a PDAC patient revealed the presence of diverse cell types in addition to tumour cells such as different immune cells, different types of fibroblasts, and a previously undescribed pancreatic cell type. Further application of this technology should yield additional insights and lead to the discovery of novel biomarkers for analysis of pancreatic cancer.

Role of C terminal binding proteins (CtBP) in pancreatic adenocarcinoma (PDAC).

320 Background: Overexpression of the oncogenic transcription factors CtBP1 and 2 is common and associated with poor prognosis in ovarian, breast and prostate cancer. CtBP2 drives tumor progression through promotion of epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) activity. Frequent early metastasis observed in PDAC may depend on EMT and CSC activity, prompting us to investigate the prognostic significance of CtBP1/2 in PDAC. In parallel, we determined the oncogenic contribution of CtBP2 to PDAC utilizing a transgenic KRAS mutant mouse PDAC model (CKP) that incorporated heterozygous loss of the Ctbp2 gene (CKP2). Methods: Immunohistochemistry (IHC) using CtBP1/2 antibodies was performed on 69 cases of resected PDAC from VCU Health for the period 2005-16. Clinical data included stage (84% stage 1/2; 16% stage 3/4), initial CA19-9 level, and overall survival. IHC stains were assigned an Allred score (sum of intensity and proportion) by two independent pathologists with a scale from 0-8. Cox Proportional Hazard survival models were fit for CtBP1/2 staining vs. survival. CtBP1/2 correlation with stage and CA19-9 level was tested by ANOVA. CKP mice were bred to Ctbp2 +/- mice, and survival of cohorts (n = 10 each) of CKP vs. CKP2 mice was analyzed by log-rank analysis of Kaplan-Meier survival curves. Results: CtBP1 and 2 expression was uniformly high (7-8) across all cases, including stage 1/2. Thus, no statistically significant survival difference could be derived based on CtBP1/2 expression [CtBP1 HR 1.03 (0.67-1.41) p 0.92, CtBP2 HR 0.75 (0.39-1.43) p 0.31], and no significant association of CtBP1/2 was seen with stage or CA19-9. Suggesting a possible contribution of CtBP2 in human PDAC, Ctbp2 knockout in CKP2 mice improved median survival (9.5 vs. 8.1 weeks, p &lt; 0.05), decreased mean tumor weight (750 mg vs. 400 mg, p &lt; 0.05), and also abrogated peritoneal metastases and ascites normally seen in 100% of CKP mice. Conclusions: While uniformly high CtBP expression in PDAC subverts prognostic use, CtBP may play a pathogenic role, as CKP2 mice exhibited improved survival, lower tumor burden and no peritoneal spread. Our data supports further study of CtBP inhibition as a potential therapeutic strategy in PDAC.

Histone profiling reveals the H1.3 histone variant as a prognostic biomarker for pancreatic ductal adenocarcinoma

BackgroundEpigenetic alterations have been recognized as important contributors to the pathogenesis of PDAC. However, the role of histone variants in pancreatic tumor progression is still not completely understood. The aim of this study was to explore the expression and prognostic significance of histone protein variants in PDAC patients.MethodsLiquid chromatography-tandem mass spectrometry (LC-MS/MS) was employed for qualitative analysis of histone variants and histone related post-translational modifications (PTMs) in PDAC and normal pancreatic tissues. Survival analysis was conducted using the Kaplan-Meier method and Cox proportional hazards regression.ResultsHistone variant H1.3 was found to be differentially expressed (p = 0.005) and was selected as a PDAC specific histone variant candidate. The prognostic role of H1.3 was evaluated in an external cohort of patients with resected PDAC using immunohistochemistry. Intratumor expression of H1.3 was found to be an important risk factor for overall survival in PDAC, with an adjusted HR value of 2.6 (95% CI 1.1–6.1), p = 0.029.ConclusionWe suggest that the intratumor histone H1.3 expression as reported herein, may serve as a new epigenetic biomarker for PDAC.

Tumor budding is a prognostic factor linked to epithelial mesenchymal transition in pancreatic ductal adenocarcinoma. Study report and literature review

BackgroundPancreatic ductal adenocarcinoma (PDAC) has a devastatingly poor prognosis. Surgical resection is undertaken in only 20% of patients. Most of well-known prognostic factors reflect tumor stage more than its biology. So it is important to identify new biological indicators related to survival in order to develop new therapies. ObjectiveTo determine the relation between tumor budding and Epithelial Mesenchymal Transition (EMT) and to evaluate their impact on survival for patients after resection of PDAC. MethodsWe herein report a retrospective study of 50 patients with resected PDAC. Tumor budding, immunohistochemical expression of vimentin and other standard factors were correlated with survival using the Kaplan-Meier method and Cox multivariable survival analysis. For tumor budding assessment, an inter-observer variability study was performed using 100 images of tumor slides stained with Hematoxylin & Eosin and Pan-Cytokeratin. ResultsTumor budding was present in all tumors. A substantial agreement between six pathologists was established in distinguishing high-grade from low-grade budding (κ = 0.6 and 0.73 for H&E and PCK images respectively). High-grade budding was identified in 56% of tumors (28/50). It was an adverse prognostic factor independent of tumor size, resection margins status, nodal status and vascular invasion (p = 0.008). Tumor budding was significantly associated with vimentin expression (p = 0.002). ConclusionsThe association of tumor budding with vimentin expression supported the idea that EMT is a key process in PDAC responsible for progression and drug resistance. Consequently, the elucidation of EMT molecular biology and development of new targeted therapy may improve disease outcome.

735P - The prognostic significance of infiltrating lymphocytes in resectable pancreatic ductal adenocarcinoma in untreated versus neoadjuvant treated patients

Background: Tumor microenvironment plays an important role in chemoresistance and tumor progression of PDAC. The role of tumor infiltrating lymphocytes in treated PDAC remains unclear. This study examines the distribution of intratumoral lymphocytes and their correlation with survival and clinicopathologic factors in patients with resected PDAC. Methods: We studied 75 patients who completed pancreaticoduodenectomy (PD) plus neoadjuvant therapies between 1999 and 2007. Neoadjuvant therapies included Gemcitabine + nab-paclitaxel and FOLFIRINOX or chemoradiation. Immunohistochemistry (IHC) for CD4, CD8, and FOXP3 were performed on resection specimens, which contained two representative slides from each patient. Digital images of IHC-stained slides were obtained at 20 x magnifications using a whole slide scanner (ScanScope, Aperio AT Turbo). Tumor regions were hand-annotated on whole slide images and computer assisted quantitative analysis was performed using Aperio’s ImageScope software. The tumor infiltrating lymphocytes were calculated as the percentage of positive staining area vs the total tumor area. Cox Regression analysis was performed for univariate and multivariate analysis. Results: The average percentage for CD4, CD8 positive cells were 6.08 ± 7.76, 2.84± 3.64, respectively in the treated cohort. Using the 50 percentile value as a cutoff, patients with high CD4+ lymphocytes had better disease free survival vs low CD4 positive lymphocytes (HR 0.234, P = 0.0031). There were no significant correlations between CD 4+, CD8+, CD68+, Granzyme B+, KP-1+, FOXP3+ lymphocytes and overall survival (p > 0.05). In multivariate analysis, neither CD4+ lymphocytes (HR: 0.49, P = 0.004), CD 8+ or CD 4/CD 8 ratio were independent prognostic factors for overall survival (See table).Table735PVariableUnivariate Analysis (DFS)Mulitivariate Analysis (DFS)P-valueHR (95% CI)P-valueHR (95% CI)CD 4 High vs. Low (Reference)0.0030.234 (0.073-0.627)0.5100.553 (0.094-3.220)CD 8 High vs. Low (Reference)0.0210.366 (0.146-0.858)0.6950.752 (0.170-2.919)CD 4/CD 8 ratio High vs. Low (Reference)0.0460.393 (0.141-0.983)0.1120.344 (0.084-1.281)CD 68/CD 4 ratio High vs. Low (Reference)0.0850.424 (0.123-1.114)0.2610.521 (0.135-1.561) Open table in a new tab Conclusions: Our study showed that the presence of high CD4+ and CD8+ lymphocytes is an independent prognostic factor for disease free survival in resectable neoadjuvant treated PDAC patients. We believe that neoadjuvant chemotherapy induces an enhanced immune response that may contribute to improved survival outcomes. Results are currently being analyzed looking at tumor infiltrating lymphocytes in resectable PDAC patients receiving receiving surgery alone. Legal entity responsible for the study: MD Anderson Cancer Center Funding: None Disclosure: All authors have declared no conflicts of interest.

Does adjuvant therapy improve overall survival for stage IA/B pancreatic adenocarcinoma?

BackgroundCurrent guidelines recommend adjuvant chemotherapy for resected pancreatic adenocarcinoma (PDAC). However, no studies have addressed its survival benefit for stage I patients as they comprise <10% of PDAC. MethodsUsing the NCDB 2006–2012, resected PDAC patients with stage I disease who received adjuvant therapy (chemotherapy or chemoradiation) were analyzed. Factors associated with overall survival (OS) were identified. Results3909 patients with resected stage IA or IB PDAC were identified. Median OS was 60.3 months (mo) for stage IA and 36.9 mo for IB. 45.5% received adjuvant chemotherapy; 19.9% received adjuvant chemoradiation. There was OS benefit for both stage IA/IB patients with adjuvant chemotherapy (HR = 0.73 and 0.76 for IA and IB, respectively, p = 0.002 and <0.001). For patients with Stage IA disease (n = 1,477, 37.8%), age ≥70 (p < 0.001), higher grade (p < 0.001), ≤10 lymph nodes examined (p = 0.008), positive margins (p < 0.001), and receipt of adjuvant chemoradiation (p = 0.002) were associated with worse OS. For stage IB patients (n = 2,432, 62.2%), similar associations were observed with the exception of adjuvant chemoradiation whereby there was no significant association (p = 0.35). ConclusionAdjuvant chemotherapy was associated with an OS benefit for patients with stage I PDAC; adjuvant chemoradiation was either of no benefit or associated with worse OS.

Low volume institutions are associated with delay and omission of adjuvant chemotherapy for resected pancreatic adenocarcinoma independent of surgical approach

Objective: Adjuvant chemotherapy (AC) in resected pancreatic adenocarcinoma (PDAC) can lead to doubled 5-year survival rates. To date, the impact of institutional volume on “rate of” and “time to” adjuvant chemotherapy (AC) for pancreaticoduodenectomy (PD), partial/distal pancreatectoemy (PP) and total pancreatectomy (TP) for PDAC has not been investigated. Methods: NCDB was queried for resected PDAC between 2010 and -2012. Patients with M1 and T1 N0 with negative margins were excluded. After correcting for confounders (age, sex, size, margins, T-,N- stage, comorbidities and hospital stay), the odds ratio (OR) of receiving and delay past 90 days of AC following PD, PP, TP for each volume quartile institution was compared to highest quartile. Factors were analyzed by multivariable regression analysis for the entire cohort and each procedure. Results: 8797 patients met inclusion criteria, 56.8% received AC with 9.5% receiving it after 90 days. AC rates for Quartile (Q) 1, Q2, Q3, and Q4 were as follows: 55.7%, 60.4%, 57.6%, 59.6%, 58.6% (p=0.016). After correcting for confounders, compared to the top quartile, Q1 and Q2 had lower odds of receiving AC. For all quartiles and procedures, time to discharge was associated with omission or delay of AC (p=0.003). Laparoscopic compared to open approach for PP in the highest 2 quartiles had higher odds of receiving AC. Only Q4 showed higher rates and lower odds of delay of AC for laparoscopic PD. Conclusion: PAC patients who have pancreatectomy at lower-volume institutions are less likely to receive AC. These data support centralization of treatment, including surgery independent of approach, for patients with PAC.

Overall survival and clinical characteristics of BRCA mutation carriers with stage I/II pancreatic cancer

Background:BRCA1/BRCA2 germ line (GL) mutation carriers with pancreatic adenocarcinoma (PDAC) may have distinct outcomes. We recently described an apparent more favourable prognosis of surgically resected BRCA-associated PDAC patients in a single-arm, uncontrolled, retrospective study. However, the prognostic impact of GL BRCA1/2 mutations in surgically resected PDAC has not been compared with a matched control population.Methods:A larger multi-centre, case–control retrospective analysis was performed. Cases were patients with surgically resected, BRCA1/2-associated PDAC from 2004 to 2013. Controls included surgically resected PDAC cases treated during the same time period that were either BRCA non-carriers, or had no family history of breast, ovarian or pancreatic cancers. Cases and controls were matched by: age at diagnosis (within ±5-year period) and institution. Demographics, clinical history, overall survival (OS) and disease-free survival (DFS) were abstracted from patient records. Statistical comparisons were assessed using χ2- and Fisher’s exact test, and median DFS/OS using Kaplan–Meier method and log-rank testing.Results:Twenty-five patients with BRCA1-(n=4) or BRCA2 (N=21)-associated resectable PDAC were identified. Mean age was 55.7 years (range, 34–78 years), 48% (n=12) were females and 76% (n=19) were Jewish. Cases were compared (1 : 2) with 49 resectable PDAC controls, and were balanced for age, ethnicity and other relevant clinical and pathological features. BRCA-associated PDAC patients received neoadjuvant, or adjuvant platinum-based treatment more frequently than controls (7 out of 8 vs 6 out of 14) and (7 out of 21 vs 3 out of 44), respectively. No significant difference in median OS (37.06 vs 38.77 months, P=0.838) and in DFS (14.3 vs 12.0 months, P=0.303) could be demonstrated between cases and controls. A trend to increased DFS was observed among BRCA-positive cases treated with neoadjuvant/adjuvant platinum-containing regimens (n=10) compared with similarly treated controls (n=7) (39.1 vs 12.4 months, P=0.255).Conclusions:In this retrospective analysis, the prognosis of surgically resectable BRCA-associated PDAC is no different than that of sporadic PDAC from the same institution. The role of platinum-based adjuvant therapy in this setting requires prospective investigation.

Radical surgery of oligometastatic pancreatic cancer

BackgroundIn metastatic disease (M1), chemotherapy (expected survival: 6–10 months) is considered the only treatment option. The aim of this study was to evaluate the outcome of curative M1 PDAC resections. MethodsProspective data of all patients undergoing primary tumour and metastasis resection for stage IV PDAC during a 12-year period was analysed regarding localisation (liver or distant interaortocaval lymph nodes; ILN), morbidity and survival. Patients were stratified with regard to syn- or metachronous metastases resection. ResultsPatients (n = 128) undergoing PDAC and metastases resection (intention-to-treat, oligometastatic stage; liver n = 85; ILN n = 43) were included. Surgical morbidity and 30-day mortality after synchronous resection of M1 tumours were 45% and 2.9%, respectively. Overall median survival after M1 resection was 12.3 months in both groups. Long-term outcome showed a 5-year survival of 8.1% after surgery for both liver metastases and 10.1% following ILN resection. ConclusionsThe present collective is the largest series of resected metastatic PDAC and shows that resection of liver or ILN metastases can be done safely and should be considered as it may be superior to palliative treatment, and it is associated with long-term survival of 10% in selected patients. Further studies to stratify patients for these procedures are warranted.