Oligometastatic Disease in Pancreatic Cancer - How to Proceed?

Characterization of an oligometastatic state in patients with metastatic pancreatic adenocarcinoma undergoing systemic chemotherapy

PURPOSE/OBJECTIVES

Most patients with pancreatic adenocarcinoma (PDAC) will present with distant metastatic disease at diagnosis. We sought to identify clinical characteristics associated with prolonged overall survival (OS) in patients presenting with metastatic PDAC.

MATERIALS/METHODS

Patients presenting with metastatic PDAC that received treatment at our institution with FOLFIRINOX or gemcitabine-based chemotherapies between August 1, 2011 and September 1, 2017 were included in the study. Metastatic disease burden was comprehensively characterized radiologically via individual diagnostic imaging segmentation. Landmark analysis was performed at 18 months, and survival curves were estimated using the Kaplan-Meier method and compared between groups via the log-rank test. ECOG and Charlson Comorbidity Index (CCI) were calculated for all patients.

RESULTS

121 patients were included with a median age of 62 years (37-86), 40% were female, 25% had ECOG 0 at presentation. Of the 121 patients included, 33% (n = 41) were alive at 12 months and 25% (n = 31) were alive at 18 months. Landmark analysis demonstrated a significant difference between patients surviving <18 months and ≥18 months regarding the presence of lung only metastases (36% vs. 16%, p = 0.04), number of organs with metastases (≥2 vs. 1, p = 0.04), and disease volume (mean of 19.1 cc vs. 1.4 cc, p = 0.04). At Year 1, predictors for improved OS included ECOG status at diagnosis (ECOG 0 vs. ECOG 1, p = 0.04), metastatic disease volume at diagnosis (≤0.1 cc vs. >60 cc, p = 0.004), metastasis only in the liver (p = 0.04), and normalization of CA 19-9 (p < 0.001). At Year 2, the only predictor of improved OS was normalization of the CA 19-9 (p = 0.03). In those patients that normalized their CA 19-9, median overall survival was 16 months.

CONCLUSIONS

In this exploratory analysis normalization of CA-19-9 or volumetric metastatic disease burden less than 0.2 cc demonstrated a remarkable OS, similar to that of patients with non-metastatic disease. These metrics are useful for counseling patients and identifying cohorts that may be optimal for trials exploring metastatic and/or local tumor-directed interventions.

Outcomes of lung oligometastasis in pancreatic cancer

OBJECTIVE

Pancreatic cancer with lung oligometastasis may have favourable overall survival. The aim of this study was to evaluate outcomes of pancreatic cancer with lung oligometastases including both synchronous and metachronous metastases.

METHODS

Consecutive pancreatic cancer patients with lung metastasis treated at our institution between February 2015 and December 2021 were identified from our prospectively maintained database. Clinical characteristics and outcomes were compared and analysed according to the extent of lung metastases. Predictors for overall survival were analysed using the Cox proportional hazards model.

RESULTS

A totoal of 171 patients were included (oligometastasis/polymetastasis/multi-organ metastasis: 34/50/87). Patients with oligometastases were more likely to undergo surgical resection (41% vs. 0% vs. 2%) and showed a longer median overall survival (41.3 vs. 17.6 vs. 13.1 months) compared with those with other types of metastases. Oligometastasis (hazard ratio, 0.43; 95% confidence interval, 0.24-0.76; P = 0.004) was identified as an independent factor predicting favourable overall survival in patients with lung-only metastasis. Disease status (synchronous vs. metachronous) was not associated with survival in patients with oligometastasis (29.4 vs. 41.3 months, P = 0.527) and polymetastasis (17.9 vs. 16.7 months, P = 0.545). Selected patients who underwent surgical resection showed a median overall survival of 52.7 months.

CONCLUSIONS

Patients with lung oligometastases presented a favourable prognosis. Surgical resection in selected patients was associated with a long median overall survival.

Nicolaioidesin C: An Antiausterity Agent Shows Promising Antitumor Activity in a Pancreatic Cancer Xenograft Mouse Model

Human pancreatic tumors are hypovascular in nature, and their tumor microenvironment is often characterized by hypoxia and severe nutrient deprivation due to uncontrolled heterogeneous growth, a phenomenon known as "austerity". However, pancreatic tumor cells have the inherent ability to adapt and thrive even in such low nutrient and hypoxic microenvironments. Anticancer drugs such as gemcitabine and paclitaxel, which target rapidly proliferating cells, are often ineffective against nutrient-deprived pancreatic cancer cells. In order to overcome this limitation, the search for novel agents that can eliminate cancer cells' adaptations to nutrition starvation, also known as "antiausterity" agents, represents a promising strategy to make the cancer cells susceptible to treatment. The natural product (+)-nicolaioidesin C (Nic-C) was found to have potent antiausterity activity against the PANC-1 human pancreatic cancer cell line in a nutrient-deprived condition. However, its efficacy in vivo remained untested. To address this, we synthesized Nic-C in its racemic form and evaluated its antitumor potential in a human pancreatic cancer xenograft model. Nic-C inhibited pancreatic cancer cell migration and colony formation and significantly inhibited tumor growth in MIA PaCa-2 xenografts in a dose-dependent manner. Furthermore, Nic-C inhibited the Akt/mTOR and autophagy signaling pathways in both in vitro and in vivo studies. Metabolomic profiling of in vivo tumor samples suggests that Nic-C downregulates amino acid metabolism while upregulating sphingolipid metabolism.

Single-cell omics: a new perspective for early detection of pancreatic cancer?

Pancreatic cancer is one of the most lethal cancers, mostly due to late diagnosis and limited treatment options. Early detection of pancreatic cancer in high-risk populations bears the potential to greatly improve outcomes, but current screening approaches remain of limited value despite recent technological advances. This review explores the possible advantages of liquid biopsies for this application, particularly focusing on circulating tumour cells (CTCs) and their subsequent single-cell omics analysis. Originating from both primary and metastatic tumour sites, CTCs provide important information for diagnosis, prognosis and tailoring of treatment strategies. Notably, CTCs have even been detected in the blood of subjects with pancreatic precursor lesions, suggesting their suitability as a non-invasive tool for the early detection of malignant transformation in the pancreas. As intact cells, CTCs offer comprehensive genomic, transcriptomic, epigenetic and proteomic information that can be explored using rapidly developing techniques for analysing individual cells at the molecular level. Studying CTCs during serial sampling and at single-cell resolution will help to dissect tumour heterogeneity for individual patients and among different patients, providing new insights into cancer evolution during disease progression and in response to treatment. Using CTCs for non-invasive tracking of cancer features, including stemness, metastatic potential and expression of immune targets, provides important and readily accessible molecular insights. Finally, the emerging technology of ex vivo culturing of CTCs could create new opportunities to study the functionality of individual cancers at any stage and develop personalised and more effective treatment approaches for this lethal disease.

Diagnostic Bioliquid Markers for Pancreatic Cancer: What We Have vs. What We Need

Pancreatic ductal adenocarcinoma (PDAC), the most common type of pancreatic cancer, currently has a dismal five-year survival rate of approximately 10% due to late diagnosis and a lack of efficient treatment options such as surgery. Furthermore, the majority of PDAC patients have surgically unresectable cancer, meaning cancer cells have either reached the surrounding blood vessels or metastasized to other organs distant from the pancreas area, resulting in low survival rates as compared to other types of cancers. In contrast, the five-year survival rate of surgically resectable PDAC patients is currently 44%. The late diagnosis of PDAC is a result of little or no symptoms in its early stage of development and a lack of specific biomarkers that may be utilized in routine examinations in the clinic. Although healthcare professionals understand the importance of early detection of PDAC, the research on the subject has lagged and no significant changes in the death toll of PDAC patients has been observed. This review is focused on understanding potential biomarkers that may increase the early diagnosis of PDAC patients at its surgically resectable stage. Here, we summarize the currently available biomarkers used in the clinic as well as those being developed with the hope of providing insight into the future of liquid biomarkers to be used in routine examinations for the early diagnosis of PDAC.

A multi-omics approach identifies pancreatic cancer cell extracellular vesicles as mediators of the unfolded protein response in normal pancreatic epithelial cells

Although cancer-derived extracellular vesicles (cEVs) are thought to play a pivotal role in promoting cancer progression events, their precise effect on neighbouring normal cells is unknown. In this study, we investigated the impact of pancreatic cancer ductal adenocarcinoma (PDAC) derived EVs on recipient non-tumourigenic pancreatic normal epithelial cells upon internalization. We demonstrate that cEVs are readily internalized and induce endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) in treated normal pancreatic epithelial cells within 24 h. We further show that PDAC cEVs increase cell proliferation, migration, and invasion and that these changes are regulated at least in part, by the UPR mediator DDIT3. Subsequently, these cells release several inflammatory cytokines. Leveraging a layered multi-omics approach, we analysed EV cargo from a panel of six PDAC and two normal pancreas cell lines, using multiple EV isolation methods. We found that cEVs were enriched for an array of biomolecules which can induce or regulate ER stress and the UPR, including palmitic acid, sphingomyelins, metabolic regulators of tRNA charging and proteins which regulate trafficking and degradation. We further show that palmitic acid, at doses relevant to those found in cEVs, is sufficient to induce ER stress in normal pancreas cells. These results suggest that cEV cargo packaging may be designed to disseminate proliferative and invasive characteristics upon internalization by distant recipient normal cells, hitherto unreported. This study is among the first to highlight a major role for PDAC cEVs to induce stress in treated normal pancreas cells that may modulate a systemic response leading to altered phenotypes. These findings highlight the importance of EVs in mediating disease aetiology and open potential areas of investigation toward understanding the role of cEV lipids in promoting cell transformation in the surrounding microenvironment.

Para-aortic lymph nodes and ductal adenocarcinoma of the pancreas: Distant neighbors?

BACKGROUND

Para-aortic lymph nodes in the ductal adenocarcinoma of the pancreatic head are regarded as distant metastases. Chemotherapy is considered the only treatment option if para-aortic lymph nodes metastases are detected preoperatively or intraoperatively. The role of standardized para-aortic lymph node lymphadenectomy during pancreaticoduodenectomy remains controversial. The aim of this study was to evaluate complication profiles and survival.

METHODS

All cases of ductal adenocarcinoma of the pancreatic head were evaluated from a prospectively maintained database (n = 289). Para-aortic lymph node lymphadenectomy was routinely performed in all patients with suspected ductal adenocarcinoma of the pancreatic head. Subgroup analysis was performed between patients with histologically positive (+) and negative (-) para-aortic lymph nodes. Patients receiving pancreaticoduodenectomy without para-aortic lymph node lymphadenectomy for other causes served as a control group.

RESULTS

A total of 192 patients received para-aortic lymph node lymphadenectomy, of which 41 were positive for para-aortic lymph node metastases. In 97 patients with ductal adenocarcinoma of the pancreatic head, no para-aortic lymph node lymphadenectomy was performed owing to postoperative pancreatic ductal adenocarcinoma diagnosis. Clinicopathologic data were homogenously distributed. Hospital stay and postoperative morbidity demonstrated no significant difference between the 3 subgroups. The median overall survival of 19.63 months (95% confidence interval: 14.57-24.79 months) in para-aortic lymph node- patients was not statistically different when compared with the median overall survival of 18.22 months (95% confidence interval: 12.68-23.75 months) in para-aortic lymph node + patients (log-rank test P = .223). Preoperative computed tomography was a poor predictor for para-aortic lymph node status (sensitivity = 10.3%, specificity = 97.8%).

CONCLUSION

This study represents the largest cohort receiving routine para-aortic lymph node lymphadenectomy. Extended lymphadenectomy can be performed safely and, although disease-free survival of para-aortic lymph node+ patients was significantly shorter, overall survival and postrelapse survival were on par with that of para-aortic lymph node- patients. Preoperative computed tomography indicating para-aortic lymph node metastasis should not preclude curative resection.

Lorlatinib Induces Durable Disease Stabilization in a Pancreatic Cancer Patient with a ROS1 p.L1950F Mutation: Case Report

INTRODUCTION

The prognosis of pancreatic cancer has improved only modestly in recent years. This is partly due to the lack of development in precision oncology including immune oncology in this entity. Rearrangements of the proto-oncogene tyrosine protein kinase ROS1 gene represent driver alterations found especially in lung cancer. Tyrosine kinase inhibitors (TKI) with activity against ROS1 including lorlatinib substantially improved the outcome of this patient population. Anecdotal evidence reports treatment of pancreatic cancer harboring ROS1 fusions with ROS1 TKI, but data concerning treatment of patients with ROS1 point mutations are lacking.

CASE PRESENTATION

This case describes a pancreatic cancer patient harboring a ROS1 point mutation that occurred without an underlying ROS1 rearrangement and thus not in the resistance situation. The heavily pretreated patient showed a strong decrease of the tumor biomarkers (CA19-9 and CEA) and radiologically a durable stable disease to the targeted treatment with lorlatinib, thereby achieving a progression-free survival of 12 months.

CONCLUSION

Our data are the first to show a clinical benefit from targeted treatment with ROS1 TKI in a cancer patient with a thus far undescribed ROS1 point mutation without a concomitant ROS1 rearrangement. Furthermore, they indicate that ROS1 could be an oncogenic driver in pancreatic cancer. This subgroup could be eligible for targeted treatments, which may contribute to the urgently needed improvement in patient outcome.

Serum Exosomal miRNA-1226 as Potential Biomarker of Pancreatic Ductal Adenocarcinoma

Background

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related mortality and it is urgent to find biomarkers for early detection of PDAC. Exosomal miRNAs are useful biomarkers for cancer detection. The aims of this study were to investigate the potential role of serum exosomal miRNA in detection of PDAC and to analyze the correlation between the levels of exosome miRNA and the tumor biological behaviors.

Materials and Methods

Thirteen serum samples were collected from five patients with PDACs, three healthy individuals (HIs) and five benign pancreatic lesions (BP) for a high throughput profiling analysis to identify an altered miRNA expression patterns in PDAC. Candidate exosomal miRNAs were filtered based on a second independent cohort that included 17 PDACs and 12 benign pancreatic lesions by quantitative real-time polymerase chain reaction (qRT-PCR). Four miRNAs were selected for miRNA validation as PDAC biomarkers in a subsequent set of samples. The association between candidate exosomal miRNA and tumor behavior (tumor invasion or metastases) was evaluated in 17 PDACs. In vitro studies were performed to evaluate the role of candidate exosomal miRNA on cell viability, apoptosis and cell migration in two PDAC cell lines.

Results

The expression of 11 miRNAs showed same trend between PDAC and BP, and between PDAC and HIs. Six of them were upregulated (miR-203b-5p, miR-342-5p, miR-337-5p, miR-149-5p, miR-877-5p, miR-203a-3p), and five were downregulated (miR-1226-3p, miR-3182, miR-625-3p, miR-624-5p, miR-664a-5p). miR-1226-3p was selected as the candidate exosomal biomarker for the PDAC detection. The expression of serum exosomal miRNA-1226-3p was downregulated in PDACs compared to the BPs (p = 0.025). miR-1226-3p had acceptable performance in predicting [area under the curve (AUC) = 0.74] PDAC. Exosomal miRNA-1226-3p level in PDAC with invasion or metastases was lower than that without invasion or metastases (p = 0.028). Transfection of miRNA-1226-3p significantly inhibited the proliferation of PANC-1 and BXP-3 cells, stimulated cell apoptosis and inhibited cell migration.

Conclusion

Serum exosomal miRNA-1226-3p is a potential biomarker in diagnosing and predicting the tumor invasion or metastases of PDAC.

Pancreatic Cancer (PDAC): Introduction of Evidence-Based Complementary Measures into Integrative Clinical Management

The most common form of pancreatic cancer is pancreatic ductal adenocarcinoma (PDAC), which comprises some 85% of all cases. Currently, this is the fourth highest cause of cancer mortality worldwide and its incidence is rising steeply. Commonly applied clinical therapies offer limited chance of a lasting cure and the five-year survival rate is one of the lowest of the commonly occurring cancers. This review cultivates the hypothesis that the best management of PDAC would be possible by integrating 'western' clinical medicine with evidence-based complementary measures. Protecting the liver, where PDAC frequently first spreads, is also given some consideration. Overall, the complementary measures are divided into three groups: dietary factors, nutraceutical agents and lifestyle. In turn, dietary factors are considered as general conditioners, multi-factorial foodstuffs and specific compounds. The general conditioners are alkalinity, low-glycemic index and low-cholesterol. The multi-factorial foodstuffs comprise red meat, fish, fruit/vegetables, dairy, honey and coffee. The available evidence for the beneficial effects of the specific dietary and nutraceutical agents was considered at four levels (in order of prominence): clinical trials, meta-analyses, in vivo tests and in vitro studies. Thus, 9 specific agents were identified (6 dietary and 3 nutraceutical) as acceptable for integration with gemcitabine chemotherapy, the first-line treatment for pancreatic cancer. The specific dietary agents were the following: Vitamins A, C, D and E, genistein and curcumin. As nutraceutical compounds, propolis, triptolide and cannabidiol were accepted. The 9 complementary agents were sub-grouped into two with reference to the main 'hallmarks of cancer'. Lifestyle factors covered obesity, diabetes, smoking, alcohol and exercise. An integrative treatment regimen was devised for the management of PDAC patients. This involved combining first-line gemcitabine chemotherapy with the two sub-groups of complementary agents alternately in weekly cycles. The review concludes that integrated management currently offers the best patient outcome. Opportunities to be investigated in the future include emerging modalities, precision medicine, the nerve input to tumors and, importantly, clinical trials.

Surgical management of oligometastatic disease in gastric cancer

A distinctive subset of metastatic gastric cancer (MGC) is oligometastatic disease (OMD), which is characterized by metastatic lesions limited in number and location. Although growing evidence mainly based on retrospective analysis or single center case series has shown favorable prognosis in the management of OMD in gastric cancer with aggressive local treatment, no existing guidelines explicitely address the definition of OMD and there are still controversial opinions on how to proceed in a new era with more effective systemic therapy selection. In this review, we present the current advances and evidence as well as controversial on the management of OMD in MGC, including the definition, diagnosis, local aggressive treatments especially surgery, prognostic factors, current ongoing randomized clinical studied as well as challenges facing the field.

Protein Kinase D1, Reduced in Human Pancreatic Tumors, Increases Secretion of Small Extracellular Vesicles From Cancer Cells That Promote Metastasis to Lung in Mice

BACKGROUND & AIMS

Pancreatic tumor cells release small extracellular vesicles (sEVs, exosomes) that contain lipids and proteins, RNA, and DNA molecules that might promote formation of metastases. It is not clear what cargo these vesicles contain and how they are released. Protein kinase D1 (PRKD1) inhibits cell motility and is believed to be dysregulated in pancreatic ductal adenocarcinomas. We investigated whether it regulates production of sEVs in pancreatic cancer cells and their ability to form premetastatic niches for pancreatic cancer cells in mice.

METHODS

We analyzed data from UALCAN and human pancreatic tissue microarrays to compare levels of PRKD1 between tumor and nontumor tissues. We studied mice with pancreas-specific disruption of Prkd1 (PRKD1^KO mice), mice that express oncogenic KRAS (KC mice), and KC mice with disruption of Prkd1 (PRKD1^KO-KC mice). Subcutaneous xenograft tumors were grown in NSG mice from Panc1 cells; some mice were then given injections of sEVs. Pancreata and lung tissues from mice were analyzed by histology, immunohistochemistry, and/or quantitative polymerase chain reaction; we performed nanoparticle tracking analysis of plasma sEVs. The Prkd1 gene was disrupted in Panc1 cells using CRISPR-Cas9 or knocked down with small hairpin RNAs, or PRKD1 activity was inhibited with the selective inhibitor CRT0066101. Pancreatic cancer cell lines were analyzed by gene-expression microarray, quantitative polymerase chain reaction, immunoblot, and immunofluorescence analyses. sEVs secreted by Panc1 cell lines were analyzed by flow cytometry, transmission electron microscopy, and mass spectrometry.

RESULTS

Levels of PRKD1 were reduced in human pancreatic ductal adenocarcinoma tissues compared with nontumor tissues. PRKD1^KO-KC mice developed more pancreatic intraepithelial neoplasia, at a faster rate, than KC mice, and had more lung metastases and significantly shorter average survival time. Serum from PRKD1^KO-KC mice had increased levels of sEVs compared with KC mice. Pancreatic cancer cells with loss or inhibition of PRKD1 increased secretion of sEVs; loss of PRKD1 reduced phosphorylation of its substrate, cortactin, resulting in increased F-actin levels at the plasma membrane. sEVs from cells with loss or reduced expression of PRKD1 had altered content, and injection of these sEVs into mice increased metastasis of xenograft tumors to lung, compared with sEVs from pancreatic cells that expressed PRKD1. PRKD1-deficient pancreatic cancer cells showed increased loading of integrin α6β4 into sEVs-a process that required CD82.

CONCLUSIONS

Human pancreatic ductal adenocarcinoma has reduced levels of PRKD1 compared with nontumor pancreatic tissues. Loss of PRKD1 results in reduced phosphorylation of cortactin in pancreatic cancer cell lines, resulting in increased in F-actin at the plasma membrane and increased release of sEVs, with altered content. These sEVs promote metastasis of xenograft and pancreatic tumors to lung in mice.

Surgical and local treatment of hepatic metastasis in pancreatic ductal adenocarcinoma: recent advances and future prospects

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease with increasing incidence and mortality. More than half of PDAC patients develop metastases, with the liver being the most common site. Patients with pancreatic ductal adenocarcinoma with liver metastases (PCLM) have a very limited scope for surgery due to aggressive tumor behavior and poor prognosis. However, with the improvements in preoperative systemic therapy and perioperative outcomes, an increasing number of patients are being considered for surgical management. However, the best choice of surgical treatment and criteria for selecting suitable PCLM patients who may benefit from surgical treatment remains controversial. Palliative local treatments, such as ablation, locoregional chemotherapy, and brachytherapy, which are less invasive and have fewer contraindications and complications, are the preferred alternatives to surgery. The present study reviews the advances in the management of PCLM, with focus on resection and local therapies.

Metastases or primary recurrence to the lung is related to improved survival of pancreatic cancer as compared to other sites of dissemination. Results of a systematic review with meta-analysis

There are demonstrations that the prognosis of patients with isolated pulmonary dissemination of pancreatic cancer is more favorable than that of patients with other patterns of disease progression. The aim of this systematic review with meta-analysis was to evaluate the oncological outcomes of pulmonary vs. non-pulmonary metastasis of patients with pancreatic cancer. A total of 11 916 patients with secondary spread of pancreatic cancer were included from 15 primary reports. In the setting of single-organ disease dissemination, the lung demonstrated a significant survival advantage over hepatic, locoregional, or peritoneal localization. In particular, patients who recurred in the lung after pancreatectomy, showed a significant survival benefit as compared to those patients with hepatic and locoregional relapse in terms of disease-free survival, survival after recurrence and overall survival.

Surgery for synchronous and metachronous single-organ metastasis of pancreatic cancer: a SEER database analysis and systematic literature review

Surgery for metastatic pancreatic cancer remains controversial as the survival benefit is questionable. The aim of the present study was to analyze the survival of these patients using data extracted from the surveillance, epidemiology, and end results (SEER) program database. Further, studies on resection for metastatic disease to the lung were systematically reviewed. A total of 11,541 cases with synchronous distant metastasis were analyzed. The median survival of single-organ metastasis was better than of multi-organ metastasis (single-organ 4.0 ± 0.07 months, two-organs 3.0 ± 0.13 months, three/four-organs 2.0 ± 0.19 months; p < 0.0001). Single organ lung metastasis had longer median survival times compared to the other sites (lung 6.0 ± 0.32 months, HR 0.87, 95% CI 0.78–0.97; p = 0.013). Resection of the primary tumor was associated with longer survival in synchronous single-organ metastasis to the lung compared to no resection (14.0 ± 1.93 months vs 6.0 ± 0.31 months, p < 0.0001). A systematic literature review identified 79 cases of metachronous lung metastasis with a survival of 120.0 ± 6.32 months and 83.0 ± 24.84 months following resection of the primary tumor and metastasis, respectively. Lower TNM staging, longer interval to metastasis, and single metastatic lesion correlated with better survival. Resection in highly selected pancreatic cancer patients with synchronous and metachronous lung only metastasis might confer a survival benefit and should be considered on an individual basis.

Long noncoding RNA LINC00657 enhances the malignancy of pancreatic ductal adenocarcinoma by acting as a competing endogenous RNA on microRNA-433 to increase PAK4 expression

A long noncoding RNAs (lncRNA) called LINC00657 is dysregulated and contributes to tumor progression in a number of human cancer types. However, there is limited information on the expression profile and functions of LINC00657 in pancreatic ductal adenocarcinoma (PDAC). The expression profile of LINC00657 in PDAC was estimated by reverse-transcription quantitative polymerase chain reaction (RT-qPCR). The effects of LINC00657 upregulation on PDAC cell proliferation, apoptosis, migration, and invasion in vitro and tumor growth in vivo were explored using CCK-8, flow cytometry, Transwell migration and invasion assays, and a xenograft tumor formation experiment, respectively. The results revealed that LINC00657 was evidently upregulated in the PDAC tumors and cell lines. High LINC00657 expression significantly correlated with the pathological T stage, lymph node metastasis, and shorter overall survival. Functional analysis demonstrated that LINC00657 knockdown inhibited the proliferation, migration, and invasion while promoted the apoptosis of PDAC cells. In addition, LINC00657 knockdown markedly suppressed tumor growth of these cells in vivo. In terms of the mechanism, LINC00657 could directly interact with microRNA-433 (miR-433) and effectively worked as an miR-433 sponge, thus decreasing the competitive binding of miR-433 to PAK4 mRNA and ultimately increasing PAK4 expression. The actions of LINC00657 knockdown on malignant phenotype of PDAC cells were strongly attenuated by miR-433 inhibition and PAK4 restoration. These results indicate that LINC00657 promotes PDAC progression by increasing the output of the miR-433-PAK4 regulatory loop, thus highlighting the importance of the LINC00657-miR-433-PAK4 network in PDAC pathogenesis.

Proposal for a definition of "Oligometastatic disease in pancreatic cancer"

BACKGROUND

To date, patients with metastasized pancreatic ductal adenocarcinoma (PDAC M1) are regarded as a uniform collective. We hypothesize the existence of oligometastatic disease (OMD): a state of PDAC M1 disease with better tumor biology, limited metastasis, and increased survival.

METHODS

Data of 128 PDAC M1 patients treated at the University of Cologne between 2008 and 2018 was reviewed. Interdependence between clinical parameter was calculated using the Mann-Whitney U-Test. Survival curves were generated using the Kaplan-Meier method and analyzed using the log-rank test.

RESULTS

Eighty-one (63%) patients had metastases confined to one organ (single organ metastasis, SOG) whereas the remaining 47 (37%) showed multiple metastatic sites (multi-organ metastasis, MOG). Survival analysis revealed a median overall survival (OS) of 12.2 months for SOG vs 4.5 months for MOG (95% CI 5.7-9.8; p < 0.001). We defined limited disease by the presence of ≤4 metastases in liver or lung. Limited disease together with CA 19-9 baseline < 1000 U/ml and response or stable disease after first-line chemotherapy defined OMD. We identified 8 patients with hepatic metastases and 2 with pulmonary metastases matching all OMD criteria. This group of 10 (7.8%) had a median overall survival of 19.4 vs 7.2 months compared to the remaining patients (95% CI 5.7-9.8; p = 0.009).

CONCLUSION

We propose a definition of oligometastatic disease in PDAC including anatomical criteria and biological criteria reflecting better tumor biology. The 10 OMD patients (7.8%) survived significantly longer and might even benefit from surgical resection in the future.

Circ-ASH2L promotes tumor progression by sponging miR-34a to regulate Notch1 in pancreatic ductal adenocarcinoma

BACKGROUND

Circular RNAs (circRNAs) have recently been shown to play important roles in different tumors. However, their detailed roles and regulatory mechanisms in pancreatic ductal adenocarcinoma (PDAC) are not well understood. This study aimed to identify enriched circRNAs and detect their functions and mechanisms in PDAC cells and tissues.

METHODS

circRNA-ASH2L (circ-ASH2L) was identified by circRNA microarray studies based on previous studies, and further detected in PDAC cells and samples by qRT-PCR. The functions of circ-ASH2L were identified by transwell, EdU, cell cycle or Tube formation assays. The regulatory mechanisms of circ-ASH2L were explored by WB, RIP, FISH, dual-luciferase assays, RNA pulldown or other assays.

RESULTS

We identified a circRNA (circ-ASH2L) based on our previous studies, detected its expression in different malignant cells and found that circ-ASH2L was highly expressed in pancreatic cells or tumor tissues and correlated with tumor malignancy. Further studies revealed that circ-ASH2L promoted tumor invasion, proliferation and angiogenesis by regulating miR-34a, thus regulate Notch 1 expression. Circ-ASH2L served as a miRNA sponge for miR-34a and promoted tumor progression in vivo. Finally, we analyzed circ-ASH2L expression in clinical tissues and found that high circ-ASH2L expression was correlated with lymphatic invasion and TNM stage and was an independent risk factor for pancreatic patient survival.

CONCLUSIONS

circ-ASH2L play an important role in tumor invasion, and high circ-ASH2L may be a useful marker of PDAC diagnosis or progression.

Tumor biology and multidisciplinary strategies of oligometastasis in gastrointestinal cancers

More than 70% of gastrointestinal (GI) cancers are diagnosed with metastases, leading to poor prognosis. For some cancer patients with limited sites of metastatic tumors, the term oligometastatic disease (OMD) has been coined as opposed to systemic polymetastasis (PMD) disease. Stephan Paget first described an organ-specific pattern of metastasis in 1889, now known as the "seed and soil" theory where distinct cancer types are found to metastasize to different tumor-specific sites. Our understanding of the biology of tumor metastasis and specifically the molecular mechanisms driving their formation are still limited, in particular, as it relates to the genesis of oligometastasis. In the following review, we discuss recent advances in general understanding of this metastatic behavior including the role of specific signaling pathways, various molecular features and biomarkers, as well as the interaction of carcinoma cells with their tissue microenvironments (both primary and metastatic niches). The unique features that underlie OMD provide potential targets for localized therapy. As it relates to clinical practice, OMD is emerging as treatable with surgical resection and/or other local therapy options. Strategies currently being applied in the clinical management of OMD will be discussed including surgical, radiation-based therapy, ablation procedures, and the results of emerging clinical trials involving immunotherapy.

Surgery for Recurrent Pancreatic Cancer: Is It Effective?

Despite improvements to surgical procedures and novel combinations of drugs for adjuvant and neoadjuvant therapies for pancreatic adenocarcinoma, the recurrence rate after radical surgery is still high. Little is known about the role of surgery in the treatment of isolated recurrences of pancreatic cancer. The aim of this study was to review the current literature dealing with surgery for recurrent pancreatic cancer in order to examine its feasibility and effectiveness. An extensive literature review was conducted according to the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and 14 articles dealing with re-resections for recurrent pancreatic adenocarcinoma were analyzed, focusing on the characteristics of the primary neoplasm and its recurrence, the surgical procedures used, and patient outcomes. Data were retrieved on a total of 301 patients. The interval between surgery for primary pancreatic cancer and the detection of a recurrence ranged from 2 to 120 months. The recurrence was local or regional in 230 patients, and distant in 71. The median overall survival was 68.9 months (range 3–152) after resection of the primary tumor, and 26.0 months (range 0–112) after surgery for recurrent disease. The disease-free interval after the resection of recurrences was 14.2 months (range 4–29). Although data analysis was performed on a heterogeneous and limited number of patients, some of these may benefit from surgery for isolated recurrence of pancreatic adenocarcinoma. Further studies are needed to identify these cases.

Aberrant expression of PDZ-binding kinase/T-LAK cell-originated protein kinase modulates the invasive ability of human pancreatic cancer cells via the stabilization of oncoprotein c-MYC

High frequency of mortality in patients with pancreatic ductal adenocarcinoma (PDAC) is vastly associated with the invasive and metastatic nature of these cancer cells. Little is known about the factors involved in this invasive/metastatic process. The current challenge in the treatment of these patients is the lack of viable options besides gemcitabine. The aim of this study was to evaluate the role of PDZ-binding kinase (PBK)/T-LAK cell-originated protein kinase (TOPK) in invasive PDAC cells and to determine whether PBK/TOPK expression drives invasiveness in PDAC. Using gain-of-function and loss-of-function studies in established and patient-derived xenograft-PDAC cell lines, and examining patient-derived archival tissue samples, we demonstrate for the first time that PBK/TOPK is upregulated in pancreatic cancer and expression levels are closely associated with the invasive property of pancreatic cancer cells. Modulation of PBK/TOPK causally regulates the invasive ability of PDAC cells. We also demonstrate that two key players in metastatic invasion, matrix metalloproteinases-2 (MMP-2) and MMP-9 gelatinase activity and gene promoter activities, are regulated by PBK/TOPK. Moreover, we demonstrate for the first time that PBK/TOPK provides stability of an oncoprotein, c-MYC, which transcriptionally regulates MMP-2 and MMP-9 in these invasive PDAC cells. Our in vitro and in situ data corroborate that PBK/TOPK is closely associated with the invasive nature of PDAC and reveal a novel mechanism by which the metastatic behavior of human pancreatic cancer cells is regulated. These findings provide a rationale for targeting PBK/TOPK for the therapeutic intervention of invasive/metastatic pancreatic cancer in human.

Long-Term Survivors in Metastatic Pancreatic Ductal Adenocarcinoma: A Retrospective and Matched Pair Analysis

BACKGROUND

Metastatic pancreatic ductal adenocarcinoma (mPDAC) is an aggressive malignancy with a median overall survival (OS) of between 8 and 11 months. However, a significant number of patients experience a longer survival, more than 18 months. The aim of this study was to describe the "long-term survivor" population and to evaluate clinical and pathological factors that might affect survival.

MATERIALS AND METHODS

All patients with mPDAC diagnosed in the Centre Leon Bérard (Lyon, France) between January 2010 and June 2015 and who survived more than 18 months were identified. They were compared with a control cohort matched on age, sex, performance status, stage at diagnosis, primary tumor localization, treatment, and liver metastasis. Their clinical features, treatment modalities, and outcomes were analyzed.

RESULTS

A total of 94 patients were included, 47 in each cohort. Both cohorts had identical characteristics as follows: women (51%), performance status ≤1 (95.7%), median age at diagnosis (60 years), and metastasis at diagnosis (83%). Median OS was 26.87 months (95% confidence interval [CI] 23-31.08) in the long-term survivor group (LS group) and 9.79 months (95% CI 5.75-11.86) in the control group (C group). Potential factors of long-term survival were explored with a logistic model (LS group vs. C group). Three factors were identified as significant prognostic factors in the univariate analysis: lymphopenia (odds ratio [OR] _{ref: yes} = 0.26), neutrophil-to-lymphocyte ratio (NLR; OR _{ref >5} = 0.31), and peritoneal carcinomatosis (OR _{ref: yes} = 0.40). NLR was the only remaining factor in our backward selection procedure.

CONCLUSION

A significant subset of patients with mPDAC can achieve long-term survival (≥18 months) in 2018. We identified low NLR as a significant prognostic factor associated with long-term survival in mPDAC.

IMPLICATIONS FOR PRACTICE

Metastatic pancreatic ductal adenocarcinoma (mPDAC) is one of the most lethal types of cancer. A subset of patients with mPDAC can achieve long-term survival (≥18 months) with a modern chemotherapy regimen, such as FOLFIRINOX or gemcitabine/nab-paclitaxel. We identified low neutrophil-to-lymphocyte ratio (NLR) as a significant prognostic factor associated with long-term survival in mPDAC. Prognostic factors such as NLR might allow accurate selection of patients with mPDAC in order to consider individual therapeutic approaches. NLR should be used as a stratification factor in clinical trials.

Surgical resection of hepatic and rectal metastases of pancreatic acinar cell carcinoma (PACC): a case report

Background

Pancreatic acinar cell carcinoma (PACC), a rare variant of pancreatic malignancy, is generally managed the same way as pancreatic ductal adenocarcinoma (PDAC). Surgical resection is the gateway to curing it; however, once it metastasizes (usually to the liver, lungs, lymph nodes, or peritoneal cavity), systemic chemotherapy has been the only option, but with unfavorable results.

Case presentation

A 67-year-old man with symptoms of loss of appetite and weight underwent surgery for malignancy of the pancreatic tail extending into the entire pancreas. The pathological diagnosis was PACC following total pancreatectomy. Twenty-four months after the pancreatectomy, a solitary liver metastasis was treated by partial hepatectomy, and, subsequently, 4 months later, he presented with melena. Further examination revealed a type-2 rectal tumor. Histological examination following biopsy revealed it to be rectal metastasis of PACC, and it was treated by abdominoperineal resection. Subsequently, the patient did not have tumor recurrence as of 40 months after pancreatectomy.

Conclusions

This is a rare case of PACC presenting with metachronal metastases in the liver and rectum, and we successfully treated them by surgical resections. Since the malignant behavior of PACC is usually less than that of PDAC, surgical resection could be an option even for metastatic lesions when the number and extent of metastases are limited.

Repurposing Established Compounds to Target Pancreatic Cancer Stem Cells (CSCs)

The diagnosis of pancreatic ductal adenocarcinoma (PDAC) carries a dismal prognosis, in particular, when patients present with unresectable disease. While significant progress has been made in understanding the biology of PDAC, this knowledge has not translated into a clear clinical benefit and current chemotherapeutic strategies only offer a modest improvement in overall survival. Accordingly, novel approaches are desperately needed. One hypothesis that could—at least in part—explain the desolate response of PDAC to chemotherapy is the so-called cancer stem cell (CSC) concept, which attributes specific traits, such as chemoresistance, metastatic potential and a distinct metabolism to a small cellular subpopulation of the whole tumor. At the same time, however, some of these attributes could make CSCs more permissive for novel therapeutic strategies with compounds that are already in clinical use. Most recently, several publications have tried to enlighten the field with the idea of repurposing established drugs for antineoplastic use. As such, recycling drugs could present an intriguing and fast-track method with new therapeutic paradigms in anti-cancer and anti-CSC treatments. Here, we aim to summarize important aspects and novel findings of this emerging field.