Tumor microenvironment in pancreatic ductal adenocarcinoma: Implications in immunotherapy

Pancreatic ductal adenocarcinoma is one of the most aggressive and lethal cancers. Surgical resection is the only curable treatment option, but it is available for only a small fraction of patients at the time of diagnosis. With current therapeutic regimens, the average 5-year survival rate is less than 10% in pancreatic cancer patients. Immunotherapy has emerged as one of the most promising treatment options for multiple solid tumors of advanced stage. However, its clinical efficacy is suboptimal in most clinical trials on pancreatic cancer. Current studies have suggested that the tumor microenvironment is likely the underlying barrier affecting immunotherapy drug efficacy in pancreatic cancer. In this review, we discuss the role of the tumor microenvironment in pancreatic cancer and the latest advances in immunotherapy on pancreatic cancer.     

Locoregional therapies and their effects on the tumoral microenvironment of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is expected to become the second leading cause of death from cancer by 2030. Despite intensive research in the field of therapeutics, the 5-year overall survival is approximately 8%, with only 20% of patients eligible for surgery at the time of diagnosis. The tumoral microenvironment (TME) of the PDAC is one of the main causes for resistance to antitumoral treatments due to the presence of tumor vasculature, stroma, and a modified immune response. The TME of PDAC is characterized by high stiffness due to fibrosis, with hypo microvascular perfusion, along with an immunosuppressive environment that constitutes a barrier to effective antitumoral treatment. While systemic therapies often produce severe side effects that can alter patients’ quality of life, locoregional therapies have gained attention since their action is localized to the pancreas and can thus alleviate some of the barriers to effective antitumoral treatment due to their physical effects. Local hyperthermia using radiofrequency ablation and radiation therapy - most commonly using a local high single dose - are the two main modalities holding promise for clinical efficacy. Recently, irreversible electroporation and focused ultrasound-derived cavitation have gained increasing attention. To date, most of the data are limited to preclinical studies, but ongoing clinical trials may help better define the role of these locoregional therapies in the management of PDAC patients.     

Recent advances in artificial intelligence for pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains the most lethal type of cancer. The 5-year survival rate for patients with early-stage diagnosis can be as high as 20%, suggesting that early diagnosis plays a pivotal role in the prognostic improvement of PDAC cases. In the medical field, the broad availability of biomedical data has led to the advent of the “big data” era. To overcome this deadly disease, how to fully exploit big data is a new challenge in the era of precision medicine. Artificial intelligence (AI) is the ability of a machine to learn and display intelligence to solve problems. AI can help to transform big data into clinically actionable insights more efficiently, reduce inevitable errors to improve diagnostic accuracy, and make real-time predictions. AI-based omics analyses will become the next alterative approach to overcome this poor-prognostic disease by discovering biomarkers for early detection, providing molecular/genomic subtyping, offering treatment guidance, and predicting recurrence and survival. Advances in AI may therefore improve PDAC survival outcomes in the near future. The present review mainly focuses on recent advances of AI in PDAC for clinicians. We believe that breakthroughs will soon emerge to fight this deadly disease using AI-navigated precision medicine.     

Radiological prediction of portal vein infiltration in patients with pancreatic ductal adenocarcinoma

BackgroundPancreatic ductal adenocarcinoma (PDAC) is an aggressive gastrointestinal malignancy characterized by early loco-regional invasion. Portal vein resection (PVR) during pancreatoduodenectomy (PD) for PDAC is performed if tumor cell invasion to the venous wall (PVI) is suspected. The aim of this study is to evaluate radiological criteria for predicting PVR and PVI.MethodsPatients undergoing PD for PDAC were identified from a prospectively maintained database. On the basis of CT- and MRI-based imaging portal vein tumor contact (PV), stranding of the superior mesenteric artery (SMA) and any alterations of the superior mesenterico-portal vein (SMPV) were evaluated. The accuracy of PVI and PVR prediction based on the radiological parameters was calculated.Results143 patients were included in the study. 48 patients underwent PVR (34%), PVI was diagnosed in 23 patients (16%). Median overall survival was 22 months. Prediction of PVR (sensitivity 79%, negative predictive value 88%, p = 0.010) and PVI (sensitivity 95%, negative predictive value 99%, p = 0.002) was most accurate for any SMPV alterations as compared to the other radiological parameters. SMPV alterations qualified as an independent prognostic parameter (26.5 months vs. 33.5months, p = 0.034).ConclusionRadiological evaluation of any SMPV alterations is a simple preoperative method to accurately predict PVI. Assessing SMPV alterations may help to identify candidates for neoadjuvant therapy.     

Adipophilin expression is an indicator of poor prognosis in patients with pancreatic ductal adenocarcinoma: An immunohistochemical analysis

Objective

Adipophilin is a lipid droplet-associated protein, and its expression has been correlated with aggressive clinical behavior in some types of carcinomas, though its role in pancreatic ductal adenocarcinoma (PDAC) has not been clarified. This study aimed to evaluate the role of adipophilin in PDAC.

Endoscopic ultrasound may be used to deliver gene expression signatures using digital mRNA detection methods to immunophenotype pancreatic ductal adenocarcinoma to facilitate personalized immunotherapy

Background & objectivesBiomarkers are increasingly required to molecularly characterize pancreatic ductal adenocarcinoma (PDAC) subgroup populations, to determine who may benefit from immune based targeted therapy. We evaluated the feasibility of gene expression signature detection and the respective landscape of specific tumor infiltrating lymphocytes (TILs), cancer/testis (CT) antigens, and immune checkpoints for possible future personalized immunotherapy eligibility.MethodsDedicated digital mRNA oncologic immune profiling of 770 genes using a Nanostring nCounter® PanCancer Immune Profiling Panel was performed using archived endoscopic ultrasound fine needle biopsy (EUS FNB) PDAC specimens as a case series in a tertiary care setting.ResultsThe spectrum of mRNA gene expression within the tumor specimens revealed that 44.8%, 10.0% and 50.7% of evaluated genes had a ≥ 2-fold increase, a ≤ 2-fold reduction or between <2 and >2 change of mRNA expression, when compared to normal controls. The corresponding landscape of TILs, CT antigens, and immune checkpoints highlighted several possibilities that could potentially be amenable to targeted personalized immunotherapy. This includes members of the Tumor Associated Macrophage family (CD68, CXCL5, and MARCO), members of the CT antigen family (PRAME, TTK and PBK) and the “second generation” checkpoints TIM3 and BTLA.ConclusionsOur study represents the ability to successfully perform digital mRNA expression profile analyses to immunophenotype PDAC EUS FNB specimens by evaluating the expression of >730 genes within the tumor immune microenvironment. This may facilitate the search for novel therapeutic targets, offering the opportunity to go beyond immune monotherapy, but perhaps to use combined immunomodulatory agents.     

Role of imaging in evaluating the response after neoadjuvant treatment for pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy. Despite the development of multimodality treatments, including surgical resection, radiotherapy, and chemotherapy, the long-term prognosis of patients with PDAC remains poor. Recently, the introduction of neoadjuvant treatment (NAT) has made more patients amenable to surgery, increasing the possibility of R0 resection, treatment of occult micro-metastasis, and prolongation of overall survival. Imaging plays a vital role in tumor response evaluation after NAT. However, conventional imaging modalities such as multidetector computed tomography have limited roles in the assessment of tumor resectability after NAT for PDAC because of the similar appearance of tissue fibrosis and tumor infiltration. Perfusion computed tomography, using blood perfusion as a biomarker, provides added value in predicting the histopathologic response of PDAC to NAT by reflecting the changes in tumor matrix and fibrosis content. Other imaging technologies, including diffusion-weighted imaging of magnetic resonance imaging and positron emission tomography, can reveal the tumor response by monitoring the structural changes in tumor cells and functional metabolic changes in tumors after NAT. In addition, with the renewed interest in data acquisition and analysis, texture analysis and radiomics have shown potential for the early evaluation of the response to NAT, thus improving patient stratification to achieve accurate and intensive treatment. In this review, we briefly introduce the application and value of NAT in resectable and unresectable PDAC. We also summarize the role of imaging in evaluating the response to NAT for PDAC, as well as the advantages, limitations, and future development directions of current imaging techniques.     

Prospective assessment of resection margin status following pancreaticoduodenectomy for pancreatic ductal adenocarcinoma after standardisation of margin definitions

BackgroundSurgical resection remains the only curative treatment for pancreatic ductal adenocarcinoma (PDAC). The prognostic value of resection margin status following pancreatoduodenectomy (PD) remains controversial. Standardised pathological assessment increases positive margins but limited data is available on the significance of involved margins. We investigated the impact of resection margin status in PDAC on patient outcome.MethodWe identified all patients with PD for PDAC at one pancreatic cancer centre between August 2008 and December 2014. Demographic, operative, adjuvant therapeutic and survival data was obtained. Pathology data including resection margin status of specific anatomic margins was collected and analysed.Results107 patients were included, all pathologically staged as T3 with 102 N1. 87.9% of patients were R1 of which 53.3% showed direct extension to the resection margin. Median survival for R0 patients versus R1<1 mm and R1 = 0 mm was 28.4 versus 15.4 and 25.1 versus 13.4 months. R1 = 0 mm status remained a predictor of poor outcome on multivariate analysis. Evaluation of individual margins (R1<1 mm) showed the SMV and SMA margins were associated with poorer overall survival. Multiple involved margins impacted negatively on outcome. SMA margin patient outcome with R1 = 1–1.9 mm was similar to R1=>2 mm.ConclusionUsing an R1 definition of <1 mm and standardised pathology we demonstrate that R1 rates in PDAC can approach 90%. R1 = 0 mm remained an independent prognostic factor for overall survival. Using R1<1 mm we have shown that involvement of medial margins and multiple margins has significant negative impact on overall survival. We conclude that not all margin positivity has the same prognostic significance.     

Overexpression of CD73 in pancreatic ductal adenocarcinoma is associated with immunosuppressive tumor microenvironment and poor survival

BackgroundCD73, a newly recognized immune checkpoint mediator, is expressed in several types of malignancies. However, CD73 expression and its impact on tumor microenvironment and clinical outcomes in pancreatic ductal adenocarcinoma (PDAC) remain unclear.MethodsThis study included two cohorts: 138 patients from our institution (MDA) and 176 patients from TCGA dataset. CD73 expression, CD4⁺, CD8⁺, CD21⁺ and CD45RO + tumor infiltrating lymphocytes (TILs) were evaluated by immunohistochemistry using tissue microarrays. The results of CD73 expression were correlated with clinicopathologic parameters, survival and TILs.ResultsCD73 overexpression correlated with poor differentiation (P = 0.002) and tumor size (P = 0.049). For CD73-low group, median overall survival (OS) and recurrence-free survival (RFS) were 26.9 ± 3.8 months and 12.6 ± 2.6 months, respectively, compared to 16.9 ± 4.4 months (P = 0.01) and 7.9 ± 1.2 months (P = 0.01), respectively, in CD73-high group. CD73 was an independent predictor for both RFS (P = 0.02) and OS (P = 0.01) by multivariate variate analysis. Similarly, CD73-high tumors had significantly shorter OS than CD73-low tumors in TCGA dataset (P < 0.0001). CD73-high correlated with decreased CD4⁺ TILs in MDA cohort and decreased CD8A and CR2 (CD21) expression in TCGA cohort.ConclusionsCD73 overexpression is associated with poor differentiation, tumor size, and shorter survival, and is an independent prognostic factor in PDAC patients. CD73 overexpression is associated with decreased CD4⁺, CD8⁺ and CD21⁺ TILs. Our data support that CD73 plays an important role in immunosuppressive tumor microenvironment and promote tumor progression in PDAC.     

Prior history of acute pancreatitis predicts poor survival in patients with resectable pancreatic ductal adenocarcinoma

Background/objectivesMounting evidence has suggested that acute pancreatitis (AP) is a risk factor for pancreatic ductal adenocarcinoma (PDAC), but its role in survival in PDAC patients was rarely investigated. The objective was to investigate the association of a history of AP with survival among PDAC patients who underwent surgical resection.MethodsA retrospective cohort study comprising 632 patients who were diagnosed with resectable PDAC was conducted. Survival was evaluated by history of AP prior to a diagnosis of PDAC using Kaplan-Meier methods and log-rank tests. Multivariate analyses for mortality were estimated using the Cox proportional hazards model. Propensity score matching methods were used to balance the difference of clinical characteristics between patients with and without AP history.ResultsThe log-rank tests showed that patients with a history of AP had a worse overall survival than those without a history of AP (p = 0.006). The multivariable-adjusted hazard ratio (HR) for mortality comparing participants with AP to those without AP was 1.808 (95% CI: 1.241–2.632, p = 0.002). Patients with a recent history of AP (<2 years), rather than patients with a remote history of AP (≥2 years), were found to have significantly worse survival (p = 0.014) than those without a history of AP. After adjusted for PSM, history of AP remained an independent survival predictor of PDAC following surgical resection.ConclusionsOur findings indicate that a history of AP, especially a recent history of AP, is associated with poor survival among patients with resectable pancreatic ductal adenocarcinoma.     

Neoadjuvant therapy for resectable pancreatic ductal adenocarcinoma: The need for patient-centered research

Pancreatic ductal adenocarcinoma is an aggressive cancer with high recurrence rates following surgical resection.While adjuvant chemotherapy improves survival,a significant proportion of patients are unable to initiate or complete all intended therapy following pancreatectomy due to postoperative complications or poor performance status.The administration of chemotherapy prior to surgical resection is an alternative strategy that ensures its early and near universal delivery as well as improves margin-negative resection rates and potentially improves long-term survival outcomes.Neoadjuvant therapy is increasingly being recommended to patients with pancreatic ductal adenocarcinoma,however,patient-centered research on its use is lacking.In this review,we highlight opportunities to focus research efforts in the domains of patient preferences,patient-reported outcomes,patient experience,and survivorship.Novel research in these areas may identify relevant barriers and facilitators to the use of neoadjuvant therapy thereby increasing its utilization,improve shareddecision making for patients and providers,and optimize the experience of those undergoing neoadjuvant therapy.     

Second pancreatectomy for recurrent pancreatic ductal adenocarcinoma in the remnant pancreas: A pooled analysis

ObjectivesThe aim of this study was to examine the outcomes of second pancreatectomy for the treatment of recurrent pancreatic ductal adenocarcinoma (PDAC) in the remnant pancreas.MethodSearch of the PubMed database was undertaken to identify relevant English language studies. Pooled individually data were examined for clinical outcomes after second pancreatectomy for recurrent PDAC.ResultsA total of 19 articles involving 55 patients were eligible for inclusion. The median disease-free interval after initial resection was 33 (range 7–143) months. Of the 55 patients reported, 52 (94.5%) patients underwent completion total pancreatectomy in the second operation for recurrences, including 15 patients who developed recurrences more than 5 years after the initial operation. There was no perioperative death. The 1-, 3- and 5-year overall survival rate after the second pancreatectomy was 82.2%, 49.2% and 40.6% respectively.ConclusionSecond pancreatectomy for recurrent PDAC can be performed safely with long-term survival in selected patients.     

Clinical characteristics of initial recurrence in lung after surgical resection for pancreatic ductal adenocarcinoma

BackgroundThe clinical characteristic differences at the initial recurrence site after resection for pancreatic ductal adenocarcinoma (PDAC) remain unknown. We investigated the clinical characteristics in patients with lung recurrence after surgical resection and evaluated the outcome of resection for isolated lung recurrence.MethodsOf 442 consecutive PDAC patients who underwent surgical resection between 2002 and 2018, 229 had recurrence on imaging. Initial recurrence sites were the liver, lung, local, peritoneal, multiple organs, and others. We analyzed the clinicopathologic factors and outcomes, comparing by initial recurrence site, and investigated the outcomes of resection for isolated lung recurrence.ResultsLiver recurrences were the most frequent (n = 60, 26%), followed by lung recurrence (n = 48, 21%). The interval from surgery to recurrence was significantly longer in lung recurrence (P = 0.0001). Patients with lung recurrence had significantly longer overall survival after diagnosis (P < 0.0001). Patients who underwent surgical resection of lung recurrence had a significantly prolonged overall survival rate after recurrence diagnosis (P = 0.004).ConclusionsPatients with lung recurrence had significantly prolonged survival than those with other recurrence patterns. Resection for isolated lung recurrence represented relatively good prognosis, and possibly may be beneficial in highly-selected patients.     

胰腺癌免疫治疗及其最新进展

胰腺癌是一种预后极差的恶性肿瘤,胰腺导管腺癌(pancreatic ductal adenocarcinoma,PDAC)是其中最常见的类型,患者被诊断时多为晚期。晚期患者在所有患者中所占比例可超过80%,这类人群的治疗主要是全身化疗,但化疗效果有限。大多数针对PDAC新疗法的研究与开发则开始关注新辅助治疗以及对各种间质成分的靶向,并且旨在缓解免疫抑制的药物疗法也备受关注,但不管是PD-1/PD-L1抗体还是CTLA-4抗体,抑或是两类药物的联合,在改善胰腺癌患者的生存方面均未能获得显著的成效。由此,我们猜测,通过对其他潜在免疫疗法的探索与研究,或许可以给胰腺癌的治疗带来新的希望。本综述旨在总结胰腺癌免疫治疗及其最新进展,通过对其进一步的理解来认识此疾病带来的治疗难点,从而有望改善其治疗策略。     

Therapeutic drug monitoring of neoadjuvant mFOLFIRINOX in resected pancreatic ductal adenocarcinoma

BackgroundDespite a potentially curative treatment, the prognosis after upfront surgery and adjuvant chemotherapy for patients with resectable pancreatic ductal adenocarcinoma (PDAC) is poor. Modified FOLFIRINOX (mFOLFIRINOX) is a cornerstone in the systemic treatment of PDAC, including the neoadjuvant setting. Pharmacokinetic-guided (PKG) dosing has demonstrated beneficial effects in other tumors, but scarce data is available in pancreatic cancer.MethodsForty-six patients with resected PDAC after mFOLFIRINOX neoadjuvant approach and included in an institutional protocol for anticancer drug monitoring were retrospectively analyzed. 5-Fluorouracil (5-FU) dosage was adjusted throughout neoadjuvant treatment according to pharmacokinetic parameters and Irinotecan (CPT-11) pharmacokinetic variables were retrospectively estimated.ResultsBy exploratory univariate analyses, a significantly longer progression-free survival was observed for patients with either 5-FU area under the curve (AUC) above 28 mcg·h/mL or CPT-11 AUC values below 10 mcg·h/mL. In the multivariate analyses adjusted by age, gender, performance status and resectability after stratification according to both pharmacokinetic parameters, the risk of progression was significantly reduced in patients with 5-FU AUC ≥28 mcg·h/mL [HR = 0.251, 95% CI 0.096–0.656; p = 0.005] and CPT-11 AUC <10 mcg·h/mL [HR = 0.189, 95% CI 0.073–0.486, p = 0.001].ConclusionsPharmacokinetically-guided dose adjustment of standard chemotherapy treatments might improve survival outcomes in patients with pancreatic ductal adenocarcinoma.     

Post-adjuvant chemotherapy CA19-9 levels predict prognosis in patients with pancreatic ductal adenocarcinoma: A retrospective cohort study

BackgroundCarbohydrate antigen 19-9 (CA19-9) is a widely used tumor marker for pancreatic ductal adenocarcinoma (PDAC). In addition, several studies have reported the utility of both pre- and postoperative CA19-9 levels as prognostic factors in resectable PDAC. However, little is known about the implications of post-adjuvant chemotherapy (AC) CA19-9 levels. The purpose of this study was to examine the utility of the post-AC CA19-9 level as a prognostic marker for relapse-free survival (RFS) in resectable PDAC.MethodsA total of 119 patients who completed AC were analyzed (normal post-AC CA19-9, n = 79; high post-AC CA19-9, n = 40). The upper limit of the normal (ULN) serum level of CA19-9 was 37 U/mL.ResultsMedian RFS was significantly shorter for patients with high post-AC CA19-9 levels than for those with normal post-AC CA19-9 (10.4 months vs. 29.6 months, respectively; p < 0.001). After adjustment, high post-AC CA19-9 level was an independent predictive factor for short RFS (hazard ratio for RFS, 2.72). Median overall survival was significantly shorter in patients with high post-AC CA19-9 levels than in those with normal postoperative CA19-9 levels (24.7 months vs. 92.1 months, respectively; p < 0.001). The optimal cutoff value of post-AC CA19-9 levels for prediction of early recurrence was >1.5 × UNL (55.5 U/mL), with a 74.2% positive predictive value.ConclusionsThe present results show that high post-AC CA19-9 level is an independent prognostic factor for short RFS in patients with resected PDAC. In addition, it may be useful for predicting early recurrence.     

Lumican蛋白在胰腺导管腺癌间质中的表达及其与Ki-67、VEGF及突变型P53表达的相关性

目的:观察细胞外基质蛋白Lumican在胰腺导管腺癌(pancreatic ductal adenocarcinoma,PDA)中表达特征,分析Lumican与Ki-67、VEGF、突变型P53等肿瘤恶性表型相关分子的关联.方法:采用免疫组织化学染色(IHC)和逆转录-聚合酶链式反应(RT-PCR)检测PDA原发灶及对应癌旁胰腺组织中Lumican表达.IHC检测PDA原发灶Ki-67、VEGF及突变型P53表达.用SPSS软件行统计学分析.结果:PDA原发灶中,Lumican表达在mRNA及蛋白质水平均明显高于癌旁胰腺组织.就该蛋白在癌灶中的分布特性而言,Lumican蛋白主要定位于癌间质,阳性表达率为83.0%(83/100).低分化PDA中,癌间质过表达Lumican与TNM分期相关(x2=6.446,P<0.05),与年龄、性别、淋巴结转移、远处转移等无明显相关.高中分化PDA中,癌间质过表达Lumican与临床病理特征无关,而与Ki-67(r=-0.28,P=0.017)、VEGF(r=-0.264,P=0.025)及突变型P53(r=-0.253,P=0.032)表达呈明显负相关.结论:Lumican在PDA原发灶中表达高于癌旁胰腺组织,主要分布于癌间质.Lumican在癌间质过表达与低分化PDA的TNM分期相关,与高、中分化PDA的Ki-67、VEGF及突变型P53表达呈负相关.