Current management and future directions in metastatic pancreatic adenocarcinoma

Metastatic Pancreatic Cancer: Where Are We?

Pancreatic cancer is one of the most lethal neoplasms worldwide; it is aggressive in nature and has a poor prognosis. The overall survival rate for pancreatic cancer is low. Most patients present non-specific symptoms in the advanced stages, which generally leads to late diagnosis, at which point there is no option for curative surgery. The treatment of metastatic pancreatic cancer includes systemic therapy, in some cases radiotherapy, and more recently, molecular targeted therapies, which can positively impact cancer control and improve quality of life. This review provides an overview of the molecular landscape of pancreatic cancer based on the most recent literature, as well as current treatment options for patients with metastatic pancreatic cancer.

Radical resection benefits patients suffering pancreatic ductal adenocarcinoma with liver oligometastases

Purpose

Whether patients suffering liver oligometastases from pancreatic ductal adenocarcinoma (LOPDA) should undergo surgical treatment remains controversial.

Methods

PubMed and Embase databases were systematically reviewed until 2023 June. Survival data were collected from the Kaplan-Meier curves. Safety and survival were evaluated using primary outcomes such as 1-year, 3-year, and 5-year survival rates, and 30-day mortality and morbidity. A subgroup meta-analysis was conducted to compare survival rates post-synchronous resection and resection post-neoadjuvant chemotherapy in LOPDA.

Results

Our analysis of 15 studies involving 1,818 patients (surgical group, 648 and nonsurgical group, 1,170) indicates that radical hepatectomy for LOPDA notably improved 1-year (odds ratio [OR], 3.24; 95% confidence interval [CI], 2.45-4.28; P < 0.001), 3-year (OR, 5.74; 95% CI, 3.36-8.90; P < 0.001), and 5-year (OR, 4.89; 95% CI, 2.56-9.35; P < 0.001) overall survival (OS) rates. A separate analysis of 6 studies with 750 patients demonstrated the safety of LOPDA surgery, with no increase in postoperative complications (P = 0.26 for overall morbidity and P = 0.99 for mortality) compared to the patients with no metastatic disease from the pancreatic ductal adenocarcinoma (NMPDA) group. The NMPDA group showed superior 1-year and 3-year OS rates, but not 5-year OS rates compared to the LOPDA group.

Conclusion

Surgical treatment apparently offers a survival advantage to LOPDA by comparing with nonsurgical groups in 1-, 3-, and 5-year OS rates. Radical resection for LOPDA is a safe treatment without more postoperative complications than NMPDA.

A pancreatic adenocarcinoma mimicking hepatoid carcinoma of uncertain histogenesis: A case report and literature review

In rare cases, metastatic adenocarcinomas of different origin may exhibit the features of hepatoid carcinoma (HC), a rare malignant epithelial tumor, most commonly occurring in the ovaries and stomach, as well as in the pancreas and biliary ducts. A case of a 72-year-old female patient who developed a highly aggressive, poorly differentiated pancreatic ductal adenocarcinoma with peritoneal carcinomatosis, demonstrating hepatoid differentiation upon conventional hematoxylin and eosin staining is reported in the present study. The patient presented with severe abdominal pain, and the radiological investigations performed revealed ovarian and hepatic tumor masses and peritoneal lesions, which were surgically removed. The gross examination of the peritoneum and omentum revealed multiple solid, firm, grey-white nodules, diffusely infiltrating the adipose tissue. The microscopic examination revealed a malignant epithelial proliferation, composed of polygonal cells with abundant eosinophilic cytoplasm and irregular, pleomorphic nuclei. Certain cells presented with intracytoplasmic mucus inclusions, raising suspicion of a HC with an uncertain histogenesis. Immunohistochemical staining was performed, and the tumor cells were found to be positive for cytokeratin (CK)7, CK18 and mucin 5AC, whereas negative staining for CK20, caudal-type homeobox transcription factor 2, α-fetoprotein, paired box gene 8, GATA-binding protein 3 and Wilms tumor 1 were documented. Thus, the diagnosis of metastatic pancreatic adenocarcinoma was established. The main aim of the present study was to provide further knowledge concerning poorly differentiated metastatic adenocarcinoma resembling HC, emphasizing the histopathological and immunohistochemical features of these malignant lesions and raising awareness of the diagnostic difficulties that may arise, as well as the importance of the use immunohistochemistry in differentiating carcinomas of uncertain histogenesis.

The Influence of MicroRNA-31 on Oxidative Stress and Radiosensitivity in Pancreatic Ductal Adenocarcinoma

Radioresistance remains a significant challenge in treating pancreatic ductal adenocarcinoma (PDAC), contributing to the poor survival rates of this cancer. MicroRNAs (miRs) are small non-coding RNA molecules that may play an essential role in regulating radioresistance by altering the levels of oxidative stress. In this study, we investigated the role and potential mechanisms linking miR-31 to PDAC radioresistance. A pCMV-miR vector containing a miR-31 mimic was stably expressed into a miR-31-deficient PDAC cell line, BxPC-3. Additionally, a pmiRZip lentivector suppressing miR-31 was stably expressed in a miR-31 abundant PDAC cell line, Panc-1. Clonogenic assays were conducted to explore the role of miR-31 manipulation on radiosensitivity. Fluorometric ROS assays were performed to quantify ROS levels. The expression of potential miR-31 targets was measured by Western blot analysis. It was found that the manipulation of miR-31 altered the radiosensitivity in PDAC cells by regulating oxidative stress. Using online bioinformatics tools, we identified the 3'UTR of GPx8 as a predicted target of miR-31. Our study demonstrates, for the first time, that manipulating miR-31 alters GPx8 expression, regulating ROS detoxification and promoting either a radioresistant or radiosensitive phenotype. MiR-31 may represent a promising therapeutic target for altering radiosensitivity in PDAC cells.

Feasibility of pancreaticoduodenectomy with synchronous liver metastasectomy for oligometastatic pancreatic ductal adenocarcinoma - A case-control study

Background

Resection of pancreatic ductal adenocarcinoma (PDAC) with synchronous liver metastasectomy is still a matter of debate. We aimed to evaluate the feasibility of synchronous resection of PDAC and liver metastases for curative intent at a high-volume surgical center.

Methods

Patients who underwent pancreaticoduodenectomy (PD) with synchronous liver metastasectomy (M1 resection group, n = 50) were matched 1 : 1 based on tumor and nodular stage, age, gender, body mass index and concomitant disease with two control groups (M0 resection and M1 no resection). The M0 resection group included patients who underwent PD without metastases. The M1 no resection group included patients with liver metastases who underwent palliative bypass or exploratory laparotomy without resection followed by palliative and adjuvant therapies.

Results

M1 resection group had a longer operation time, larger intraoperative blood loss, and longer postoperative hospital stay than other two groups. R0 resection rate of M1 resection group was similar to that of M0 resection group (92% vs. 94%, p = 1.000). Postoperative complications were comparable between the groups. The overall median survival in M1 resection, M0 resection, and M1 no resection group was 16, 30, and 6 months, respectively. Cumulative survival rates for 1-, 2-, and 3-year of the M1 resection, M0 resection, and M1 no resection group were 63.8%, 29.0%, and 6.7%; 94.0%, 74.4%, and 25.1%; 24.0%, 2.0%, and 0%, respectively. The survival of M1 resection group was worse than that of M0 resection group (p = 0.009), however significantly much better than that of M1 no resection group (p = 0.001). Univariate analysis showed carcinoembryonic antigen >8 ng/ml and non-R0 resection were associated with death. Multivariate analysis revealed that M1 resection group had improved survival compared with M1 no resection group.

Conclusions

PD with synchronous liver metastasectomy for oligometastatic PDAC is safe and feasible, it might provide survival benefits for selected patients.

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A retrospective, case–control study was conducted at a high-volume surgical center.

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50 patients underwent pancreaticoduodenectomy with synchronous liver metastasectomy.

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Complications were similar in M1 resection, M0 resection and M1 no resection groups.

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Carcinoembryonic antigen >8 ng/ml and non-R0 resection were associated with death.

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The survival of M1 resection group was much better than that of M1 no resection.

Objective assessment of tumor regression in post-neoadjuvant therapy resections for pancreatic ductal adenocarcinoma: comparison of multiple tumor regression grading systems

Neoadjuvant therapy is increasingly used to control local tumor spread and micrometastasis of pancreatic ductal adenocarcinoma (PDAC). Pathology assessments of treatment effects might predict patient outcomes after surgery. However, there are conflicting reports regarding the reproducibility and prognostic performance of commonly used tumor regression grading systems, namely College of American Pathologists (CAP) and Evans' grading system. Further, the M.D. Anderson Cancer Center group (MDA) and the Japan Pancreas Society (JPS) have introduced other grading systems, while we recently proposed a new, simple grading system based on the area of residual tumor (ART). Herein, we aimed to assess and compare the reproducibility and prognostic performance of the modified ART grading system with those of the four grading systems using a multicenter cohort. The study cohort consisted of 97 patients with PDAC who had undergone post-neoadjuvant pancreatectomy at four hospitals. All patients were treated with gemcitabine and S-1 (GS)-based chemotherapies with/without radiation. Two pathologists individually evaluated tumor regression in accordance with the CAP, Evans', JPS, MDA and ART grading systems, and interobserver concordance was compared between the five systems. The ART grading system was a 5-tiered system based on a number of 40× microscopic fields equivalent to the surface area of the largest ART. Furthermore, the final grades, which were either the concordant grades of the two observers or the majority grades, including those given by the third observer, were correlated with patient outcomes in each system. The interobserver concordance (kappa value) for Evans', CAP, MDA, JPS and ART grading systems were 0.34, 0.50, 0.65, 0.33, and 0.60, respectively. Univariate analysis showed that higher ART grades were significantly associated with shorter overall survival (p = 0.001) and recurrence-free survival (p = 0.005), while the other grading systems did not show significant association with patient outcomes. The present study revealed that the ART grading system that was designed to be simple and more objective has achieved high concordance and showed a prognostic value; thus it may be most practical for assessing tumor regression in post-neoadjuvant resections for PDAC.

Vestigial-like 1 is a shared targetable cancer-placenta antigen expressed by pancreatic and basal-like breast cancers

Cytotoxic T lymphocyte (CTL)-based cancer immunotherapies have shown great promise for inducing clinical regressions by targeting tumor-associated antigens (TAA). To expand the TAA landscape of pancreatic ductal adenocarcinoma (PDAC), we performed tandem mass spectrometry analysis of HLA class I-bound peptides from 35 PDAC patient tumors. This identified a shared HLA-A*0101 restricted peptide derived from co-transcriptional activator Vestigial-like 1 (VGLL1) as a putative TAA demonstrating overexpression in multiple tumor types and low or absent expression in essential normal tissues. Here we show that VGLL1-specific CTLs expanded from the blood of a PDAC patient could recognize and kill in an antigen-specific manner a majority of HLA-A*0101 allogeneic tumor cell lines derived not only from PDAC, but also bladder, ovarian, gastric, lung, and basal-like breast cancers. Gene expression profiling reveals VGLL1 as a member of a unique group of cancer-placenta antigens (CPA) that may constitute immunotherapeutic targets for patients with multiple cancer types.

Significant response to anti-PD-1 based immunotherapy plus lenvatinib for recurrent intrahepatic cholangiocarcinoma with bone metastasis: A case report and literature review

INTRODUCTION

The prognosis for recurrent intrahepatic cholangiocarcinoma with bone metastasis remains dismal and its treatment poses a challenge for oncologists. To date, only 2 cases were reported in which pembrolizumab, an agent against programmed cell death protein-1 (PD-1), combined with chemotherapy led to a complete response. The safety and efficacy of nivolumab-based immunotherapy combined with lenvatinibin intrahepatic cholangiocarcinoma is unknown.

PATIENT CONCERNS

A 40-year-old female was identified as having a lesion of 7.0 cm in diameter in the right lobe of the liver. In addition, calculi in the main and left hepatic bile ducts as well as the gallbladder were found.

DIAGNOSIS

Based on the results of imaging studies and tumor biomarker level, the patient was initially diagnosed as having intrahepatic cholangiocellular carcinoma and cholelithiasis, after which surgery was performed. The pathological examination confirmed that the tumor was cholangiocarcinoma. Adjuvant chemotherapy was administered after surgery. However, the patient developed recurrent lesions at the 5th month after surgery, and the cholangiocarcinoma expanded to the right thoracic vertebral pedicle (T7-8) at the 6th month.

INTERVENTIONS

The patient underwent percutaneous microwave ablation after recurrence in the liver was identified. After that, the patient received nivolumab plus lenvatinib.

OUTCOMES

The lesions in the liver decreased in size and disappeared after treatment with nivolumab plus lenvatinib. Additionally, the metastases in the right thoracic vertebral pedicle were stable after 9 months of therapy.

LESSONS

Immunotherapy has revolutionized the treatment of non-small-cell lung cancer, melanoma, and advanced renal cell carcinoma. In this case, the patient achieved an excellent radiological and symptomatic response after receiving nivolumab plus lenvatinib combination therapy. Patients suffering from cholangiocarcinoma with dMMR status and a high tumor mutation burden (TMB) may have a consistent eutherapeutic effect with anti-PD-1-directed treatment.

Downregulation of lncRNA AFAP1-AS1 by oridonin inhibits the epithelial-to-mesenchymal transition and proliferation of pancreatic cancer cells

Recent studies have demonstrated that the expression of the long non-coding RNA (lncRNA) AFAP1-AS1 in pancreatic cancer is negatively correlated with survival and prognosis. However, the effects of oridonin and lncRNA AFAP1-AS1 on the epithelial-to-mesenchymal transition (EMT) and migration of pancreatic cancer cells have not been fully elucidated. Surgery is the only potentially curative method for pancreatic cancer, but postoperative recurrence and metastasis are common. The aim of the present study was to assess the effect of oridonin and lncRNA AFAP1-AS1 silencing on pancreatic cancer cells. The pancreatic cancer cell lines BxPC-3 and PANC-1 cells were transfected with siAFAP1-AS1 and its negative control (siNC). After that, oridonin was used to treat the siAFAP1-AS1-transfected cells. The expression of lncRNA AFAP1-AS1 was downregulated in the pancreatic cancer cell lines BxPC-3 and PANC-1. The apoptosis and cell cycle progression of pancreatic cancer cells were evaluated by flow cytometry and Hoechst 33258 staining. Metastasis and invasion of BxPC-3 and PANC-1 cells were detected by transwell migration assay, real-time cell analysis, and western blot analysis. Cells were transfected with the lentiviral siAFAP1-AS1 and siNC, and tumorigenesis was evaluated in BALB/C nude mice. Immunohistochemical examination was used to verify the effects of oridonin and siAFAP1-AS1 on pancreatic cancer. The results demonstrated that the combination of oridonin and siAFAP1-AS1 inhibited pancreatic cancer cell proliferation, induced apoptosis, arrested cell cycle progression, prevented the migration, regulated EMT-related protein expression in BxPC-3 and PANC-1 cells, and inhibited pancreatic cancer cell tumorigenicity and EMT in nude mice.

The Impact of Epidemiological Factors and Treatment Interventions on Survival in Patients With Signet Ring Cell Carcinoma of the Pancreas

OBJECTIVES

Primary pancreatic signet ring cell carcinoma (SRCC) is a rare histologic variant of pancreatic carcinoma. A population-based analysis of pancreatic SRCC was performed to determine the predictive effects of epidemiological factors and treatment interventions on overall survival (OS) and disease-specific survival (DSS).

MATERIALS AND METHODS

The Surveillance, Epidemiology, and End Results registry was searched for pancreatic SRCC cases diagnosed between January 1, 1973 and December 31, 2013. Statistical analysis was performed using the Fisher exact test, χ(2) analysis, Kaplan-Meier method, log-rank test, and Cox proportional hazards regression.

RESULTS

The mean age among 497 patients was 66.6 years (SD, 11.9). Most patients were white (82.7%) and male (54.5%). The 1-, 2-, and 5-year OS rates were 17%, 9%, and 4%, respectively, while the corresponding 1-, 2-, and 5-year rates for DSS were 18%, 10%, and 5%, respectively. On univariable analysis; age, site, grade, stage, and treatment were predictive of OS and DSS (P<0.05). On multivariable analysis; radiation improved OS and DSS (adjusted hazard ratio [aHR], 0.592 and 0.589, respectively), pancreatectomy improved OS and DSS (aHR, 0.360 and 0.355, respectively), and combination therapy improved OS and DSS (aHR, 0.295 and 0.286, respectively). Age, site, and stage were also independent predictors of OS and DSS. Subgroup analysis demonstrated treatment to be an independent predictor of OS and DSS in localized/regional disease, in distant disease, and in patients diagnosed between 2000 and 2013.

CONCLUSIONS

Age, site, stage, and treatment independently predict OS and DSS in pancreatic SRCC.

Vasohibin 2 promotes malignant behaviors of pancreatic cancer cells by inducing epithelial-mesenchymal transition via Hedgehog signaling pathway

Background

Based on previous findings, we hypothesized that Vasohibin 2 (VASH2) protein may induce epithelial‐mesenchymal transition (EMT) of pancreatic cancer (PC) cells by promoting the malignant behaviors of these cells. The present study aimed to test this hypothesis and explore the possible mechanisms involved.

Methods

The expression of VASH2 in PC tissues and cell lines was detected by quantitative real‐time PCR and Western blot. PC cells with overexpression or knockdown of VASH2 were used to examine the involvement of VASH2 in EMT by detecting the expression of epithelial (E‐cadherin) and mesenchymal (vimentin) markers and EMT‐related transcription factor ZEB1/2, in gemcitabine resistance and tumor cell invasion by apoptosis and invasion assays, and in cancer stem cell‐like phenotypes by detecting the proportion of CD24⁺CD44⁺ and side population (SP) cells in PC cells with flow cytometry. The impact of VASH2 overexpression and knockdown on components of the Hedgehog signaling pathway was also assessed.

Results

We found that VASH2 was highly expressed in PC tissues and cells. It promoted the EMT of PC cells by altering ZEB1/2 expression. VASH2 also stimulated invasion and chemotherapeutic resistance of PC cells and increased the proportion of cancer stem‐like cells in PC cells. VASH2 did so by upregulating the expression of multiple molecules in the Hedgehog signaling pathway of PC cells.

Conclusion

VASH2 promotes malignant behaviors of PC cells by inducing EMT via activation of the Hedgehog signaling pathway.

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

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

Strategies for Increasing Pancreatic Tumor Immunogenicity

Immunotherapy has changed the standard of care for multiple deadly cancers, including lung, head and neck, gastric, and some colorectal cancers. However, single-agent immunotherapy has had little effect in pancreatic ductal adenocarcinoma (PDAC). Increasing evidence suggests that the PDAC microenvironment is comprised of an intricate network of signals between immune cells, PDAC cells, and stroma, resulting in an immunosuppressive environment resistant to single-agent immunotherapies. In this review, we discuss differences between immunotherapy-sensitive cancers and PDAC, the complex interactions between PDAC stroma and suppressive tumor-infiltrating cells that facilitate PDAC development and progression, the immunologic targets within these complex networks that are druggable, and data supporting combination drug approaches that modulate multiple PDAC signals, which should lead to improved clinical outcomes. Clin Cancer Res; 23(7); 1656-69. ©2017 AACRSee all articles in this CCR Focus section, "Pancreatic Cancer: Challenge and Inspiration."

Evaluation of the 8th AJCC staging system for pathologically versus clinically staged pancreatic adenocarcinoma: A time to revisit a dogma?

BACKGROUND

The 8th edition of the American Joint Committee on Cancer (AJCC) staging system for pancreatic exocrine adenocarcinoma has been released. The current study seeks to assess the 7th and 8th editions among patients registered within the surveillance, epidemiology and end results (SEER) database.

METHODS

SEER database (2010-2013) has been accessed through SEER*Stat program and AJCC 8th edition stages were reconstructed utilizing the collaborative stage descriptions. Kaplan-Meier analysis of overall survival and pancreatic cancer-specific survival analyses (according to both 7th and 8th editions and according to whether pathological or clinical staging were conducted) has been performed. Multivariate analysis of factors affecting pancreatic cancer-specific survival was also conducted through a Cox proportional hazard model.

RESULTS

A total of 18  948 patients with pancreatic adenocarcinoma were identified in the period from 2010-2013. Pancreatic cancer-specific survival among pathologically staged patients and according to the 8th edition showed significant differences for all pair wise comparisons among different stages (P < 0.0001) except for the comparison between stage IA and stage IB (P = 0.307) and the comparison between stage IB and stage IIA (P = 0.116). Moreover, P value for stage IA vs IIA was 0.014; while pancreatic cancer-specific survival according to the 7th edition among pathologically staged patients showed significant differences for all pair wise comparisons among different stages (P < 0.0001) except for the comparison between IA and IB (P = 0.072), the comparison between stage IIA and stage IIB (P = 0.065), the comparison between stage IIA and stage III (P = 0.059) and the comparison between IIB and III (P = 0.595). Among clinically staged patients (i.e. those who did not undergo initial radical surgery), the prognostic performance of both 7th and 8th stages for both overall survival and pancreatic cancer-specific survival was limited.

CONCLUSION

There is clearly a need to have two staging systems for pancreatic adenocarcinoma: pathological and clinical staging systems.

HALO-109-301: a Phase III trial of PEGPH20 (with gemcitabine and nab-paclitaxel) in hyaluronic acid-high stage IV pancreatic cancer

The outlook for patients with advanced pancreatic cancer remains poor, despite significant advances in our understanding of pancreatic tumor biology. One emerging theme highlights the distinct composition of the pancreatic tumor microenvironment. Hyaluronic acid is a hydrophilic glycosaminoglycan whose production within the tumor leads to increased interstitial tumor pressure, thereby limiting the access of potentially effective circulating anticancer drugs via reduced tumor perfusion. PEGylated rHuPH20 is a multiply PEGylated recombinant human hyaluronidase that has shown promising efficacy in preclinical models and early phase clinical trials in pancreatic cancer patients. Here, we discuss these findings, and the rationale for the ongoing randomized Phase III trial (HALO-109-301), which seeks to definitively define the efficacy of PEGylated rHuPH20 alongside gemcitabine and nab-paclitaxel in previously untreated, hyaluronic acid-high, stage IV pancreatic cancer.

Fractalkine/CX3CR1 axis modulated the development of pancreatic ductal adenocarcinoma via JAK/STAT signaling pathway

Pancreatic ductal adenocarcinoma (PDAC) is a fatal malignancy with an estimated 5 year survival rate of approximately 5% of all stages combined. High potential of PDAC metastasis is a leading cause for high mortality and poor prognosis. The majority of patients present with distant metastasis at diagnosis. Fractalkine (FKN) is recognized as a chemokine and a specific ligand of CX3CR1. It has been reported that FKN/CX3CR1 system was upregulated in many types of solid tumors. However, role of FKN/CX3CR1 in PDAC development remains unclear. In the current investigation, we found that FKN and CX3CR1 expression was significantly increased in PDAC tissues, especially in the metastatic samples, and was highly-correlated with severity of PDAC. Ectopic expression of FKN promoted the proliferation and migration of PDAC, while knockdown of CX3CR1 reversed the function of FKN. In addition, PDAC cells with FKN-deficiency showed impaired proliferation and migration activity. The underlying mechanism is that FKN/CX3CR1 activated JAK/STAT signaling, which in turn regulated cell growth. Consistently, in vivo tumorigenesis assay validated the regulatory role of FKN/CX3CR1 in PDAC growth. Our investigation helped understanding the pathogenesis of PDAC occurrence, and demonstrated critical role of FKN/CX3CR1 in PDAC development.

Prognostic value of site-specific metastases in pancreatic adenocarcinoma: A Surveillance Epidemiology and End Results database analysis

AIM

To evaluate the prognostic value of site-specific metastases among patients with metastatic pancreatic carcinoma registered within the Surveillance, Epidemiology and End Results (SEER) database.

METHODS

SEER database (2010-2013) has been queried through SEER*Stat program to determine the presentation, treatment outcomes and prognostic outcomes of metastatic pancreatic adenocarcinoma according to the site of metastasis. In this study, metastatic pancreatic adenocarcinoma patients were classified according to the site of metastases (liver, lung, bone, brain and distant lymph nodes). We utilized chi-square test to compare the clinicopathological characteristics among different sites of metastases. We used Kaplan-Meier analysis and log-rank testing for survival comparisons. We employed Cox proportional model to perform multivariate analyses of the patient population; and accordingly hazard ratios with corresponding 95%CI were generated. Statistical significance was considered if a two-tailed P value < 0.05 was achieved.

RESULTS

A total of 13233 patients with stage IV pancreatic cancer and known sites of distant metastases were identified in the period from 2010-2013 and they were included into the current analysis. Patients with isolated distant nodal involvement or lung metastases have better overall and pancreatic cancer-specific survival compared to patients with isolated liver metastases (for overall survival: lung vs liver metastases: P < 0.0001; distant nodal vs liver metastases: P < 0.0001) (for pancreatic cancer-specific survival: lung vs liver metastases: P < 0.0001; distant nodal vs liver metastases: P < 0.0001). Multivariate analysis revealed that age < 65 years, white race, being married, female gender; surgery to the primary tumor and surgery to the metastatic disease were associated with better overall survival and pancreatic cancer-specific survival.

CONCLUSION

Pancreatic adenocarcinoma patients with isolated liver metastases have worse outcomes compared to patients with isolated lung or distant nodal metastases. Further research is needed to identify the highly selected subset of patients who may benefit from local treatment of the primary tumor and/or metastatic disease.

Pancreatic Cancer, A Mis-interpreter of the Epigenetic Language

Pancreatic cancer is the third leading cause of cancer mortality in the U.S. with close to 40,000 deaths per year. Pancreatic ductal adenocarcinoma (PDAC) represents approximately 90 percent of all pancreatic cancer cases and is the most lethal form of the disease. Current therapies for PDAC are ineffective and most patients cannot be treated by surgical resection. Most research efforts have primarily focused on how genetic alterations cause, alter progression, contribute to diagnosis, and influence PDAC management. Over the past two decades, a model has been advanced of PDAC initiation and progression as a multi-step process driven by the acquisition of mutations leading to loss of tumor suppressors and activation of oncogenes. The recognition of the essential roles of these genetic alterations in the development of PDAC has revolutionized our knowledge of this disease. However, none of these findings have turned into effective treatment for this dismal malignancy. In recent years, studies in the areas of chromatin modifications, and non-coding RNAs have uncovered mechanisms for regulating gene expression which occur independently of genetic alterations. Chromatin-based mechanisms are interwoven with microRNA-driven regulation of protein translation to create an integrated epigenetic language, which is grossly dysregulated in PDAC. Thus in PDAC, key tumor suppressors that are well established to play a role in PDAC may be repressed, and oncogenes can be upregulated secondary to epigenetic alterations. Unlike mutations, epigenetic changes are potentially reversible. Given this feature of epigenetic mechanisms, it is conceivable that targeting epigenetic-based events promoting and maintaining PDAC could serve as foundation for the development of new therapeutic and diagnostic approaches for this disease.