PDAC Peripheral and Portal Vein Sampling
PDAC Peripheral and Portal Vein Sampling
This is a research study in which bio-specimens (whole blood, plasma and serum from
 peripheral circulation and portal vein) will be collected from patients with pancreatic
 adenocarcinoma for translational research. These samples will be used for (but not limited
 to) identification and characterisation of blood-borne biomarkers at the genomic and protein
 expression level. Examples of such biomarkers are circulating tumour cells (CTCs), CTC
 clusters and circulating DNA (which can be tumour derived, or from unaffected/normal cells).
 CTC-enriched blood samples may also be used to generate CTC-derived tumour explant (CDX)
 models in immunocompromised mice in order to produce suitable disease models in which to test
 novel therapies and identify new molecular targets. In addition, permission will be sought
 from study participants for the research team to access clinical information from medical
 notes to aid in determining the clinical relevance of biomarkers identified during the course
 of this study. Validated biomarkers are anticipated to be used in designing future
 biomarker-directed clinical trials in these disease groups.
Pancreatic Ductal Adenocarcinoma (PDAC) presents an urgent medical need. Approximately 9000
 new cases of pancreatic cancer are diagnosed every year in the United Kingdom (UK) and
 worldwide it is projected to become the second most common cause of cancer related death by
 2030. Currently the diagnostic pathway starts with pancreatic protocol Computed Tomgraphy
 (CT) scan which demonstrates sensitivity of 90% and specificity of 99% in diagnosis of
 pancreatic cancer. Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET)
 can assist with ambiguous masses. Despite the high sensitivity and specificity of imaging
 modalities, definitive diagnosis is routinely obtained only by endoscopic ultrasound
 (EUS)-guided fine-needle aspiration (FNA). During this procedure four "passes" (biopsies) on
 average are required to obtain sufficient tissue for diagnosis.

 Patients usually present with locally advanced or metastatic disease and are offered standard
 of care chemotherapy, which has only a limited impact on overall survival. Consequently the
 5-year overall survival (OS) is only 2% with no significant improvement over the last 40
 years. Approximately only 20% of the patients are eligible for surgical resection which is
 followed by adjuvant chemotherapy. However, 66% of these patients will experience local or
 distant recurrence, leading to a median overall survival in the range of 28 months. Improved
 stratification of patients for existing treatments may thus avoid unnecessary overtreatment
 and associated side effects to improve quality of life; conversely, it may also enable
 selection for a more appropriate treatment.

 A significant reason for the lack of progress in tackling metastatic disease is the poor
 understanding of the biology and pathophysiology of metastasis. Studying the biology of PDAC
 metastasis is hampered by the fact that it is difficult to obtain tissue from the primary and
 metastatic sites. Moreover, serial biopsies following progression during treatment is largely
 not feasible, further hindering insight into the mechanisms of development of treatment
 resistance. The only easily-accessible blood-borne biomarker that is currently used in clinic
 is the serum marker carbohydrate antigen (CA) 19-9. However, its clinical use is limited
 firstly by the fact that 5-10% of the population are Lewis blood group negative and do not
 express CA19-9. Furthermore it is elevated in non-malignant pancreatic and extra-pancreatic
 diseases. Finally, CA19-9 cannot provide information about the genetic landscape that drives
 PDAC metastasis.

 Metastatic spread is primarily haematogenous whereby tumour cells enter the circulation to
 metastasize mainly to the liver and lung. Such tumour cells have been shown to travel either
 as single circulating tumour cells (CTCs) or as groups of cells termed Circulating Tumour
 Microemboli (CTM). Heterogeneous CTM composed of cells expressing either epithellial or
 mesenchymal markers were isolated from patients with pancreatic cancer using a
 filtration-based method, the Isolation by Size of Epithelial Tumour cells platform (ISET), in
 a study performed at the Christie NHS Foundation Trust. As such, isolation and
 characterisation of CTCs and CTM will provide new insight into the underlying biological
 dependencies of metastasizing tumour cells and may thus provide opportunities to develop
 better and more accurate diagnostic and prognostic assays as well as opportunities to treat
 metastatic disease.

 Detection and isolation of CTCs and CTM is limited by the fact that they represent very rare
 events compared to other cellular elements in the circulation. To this end, methods
 exploiting characteristics that differentiate CTCs from blood cells have been developed to
 overcome this obstacle. These CTC workflows usually start by enriching CTCs from a blood
 sample utilizing either surface markers present exclusively on CTCs, or their unique physical
 properties such as size, inertia, dielectric charge and density. Following enrichment, CTCs
 are isolated and can be simply enumerated or they are used for more advanced downstream
 analysis including genomic, transcriptomic and proteomic analysis as well as in vivo
 applications in cell culture and mouse models, with the aim of gaining insight into their
 function as metastatic seeds and biomarker development.

 In the clinical setting, CTCs can be used to aid decision making. Indeed, enumeration of CTCs
 detected by the CellSearch platform has been FDA approved for prognosis and monitoring of
 metastatic breast, colorectal and prostate cancer. However, isolation and enumeration of CTCs
 in pancreatic cancer has given inconsistent results between studies as to whether CTCs can be
 used as prognostic biomarkers. These studies analysed CTCs isolated from peripheral blood.
 However, as the main venous drainage of the pancreas is through the portal vein to the liver,
 it may be hypothesized that CTCs could be filtered and removed as they pass through the liver
 capillaries. Hence, in order to define the biological and prognostic role of CTCs in
 pancreatic adenocarcinoma, it is critical to initiate studies with blood isolated from the
 portal vein to bypass confounding effects. Indeed, detection of CTCs in portal vein (PV)
 blood acquired at operation was recently reported by Bissolati et al.. By obtaining
 peripheral vein samples at the same time, this study confirmed that CTC number was greater in
 portal compared to peripheral samples and also demonstrated significant correlation between
 CTC positivity in portal vein samples and frequency on liver metastasis. However, it failed
 to show significant correlation with OS or Disease Free Survival (DFS). PV sampling has been
 performed safely; in December 2015 Catenacci et al. reported collection of PV blood from 18
 patients with pancreatobilliary cancers by EUS-FNA with no complications during the
 procedure. PV puncture has also been previously reported for islet cell transplantation in
 patients with Type 1 Diabetes Mellitus. This procedure has low morbidity and also, potential
 complications, such as portal vein thrombosis, perihepatic or intraparenchymal hepatic
 haemorrhage and haemothorax are reported at a low rate.

 During EUS-FNA a curvilinear echoendoscope is advanced to the distal stomach or duodenal bulb
 to provide a window of access to a branch of the PV. After verifying venous flow by Doppler
 signal, a 19-gauge EUS-FNA needle is advanced transhepatically into the portal vein branch.
 With the needle in the portal vein, the stylet is removed and negative-pressure suction is
 applied to aspirate blood. A transhepatic approach for portal vein branch access is an
 absolute requirement of this technique in order to minimize the risk of bleeding. The
 puncture site is monitored under EUS for complications. As tumour tissue will be obtained at
 the same time, a potential risk is the introduction of cancer cells into the circulation as
 the needle is withdrawn from the tumour. This risk however is circumvented as the route of
 the needle into the portal vein would avoid the primary mass.

 The primary reason for drug failure in PDAC is the failure to identify predictive biomarkers
 for treatment response which would allow enrichment of patient sub-groups most likely to
 benefit from an individual therapy. This is in contrast to other major cancer types, in which
 advances in development of new cancer therapeutics and resulting improvement in survival
 outcomes are mainly due to the use of predictive biomarkers to select patients who will
 derive differential benefit from a particular therapeutic agent. Trastuzumab in breast
 cancers over-expressing HER-2, cetuximab for KRAS wild-type colorectal cancer, and gefitinib
 and erlotinib for Epidermal Growth Factor Receptor (EGFR) mutant non-small cell lung cancer
 best exemplify this therapeutic paradigm. By providing greater numbers of CTCs and CTM,
 analysis of PV sample will enable studies of their biology as well as development of cell
 lines and CDX models to allow identification of novel biomarkers and targets for new
 treatments.

 Considering current gaps in knowledge of tumour biology of PDAC and the lack of progress in
 therapeutics, there is an urgent clinical need to develop a research strategy that will allow
 the discovery and validation of new biomarkers in this group of patients, and inform on
 biomarker-directed clinical trials to ultimately improve survival. To initiate such a
 research strategy, there is a need for systematic, prospective collection and analysis of
 blood samples acquired from peripheral and portal vein circulation to identify blood-borne
 surrogate tumour markers that will enable physicians to obtain relevant information for
 making personalised therapeutic decisions, in a minimally-invasive way.
Inclusion Criteria:

 1. Patients with clinically-suspected or cytologically/histologically-proven Pancreatic
 Adenocarcinoma who have been referred for EUS-FNA. Patients who are already on
 treatment would also be eligible.

 2. Patients who are 18 years or older.

 3. Patients must be able to receive and understand verbal and written information
 regarding the study and give written informed consent.

 4. Patients must be able to comply with trial requirements.

 Exclusion Criteria:

 1. Patients with other active malignancy would not be eligible with the exception of
 patients with squamous or basal cell carcinoma of the skin. An exception to this
 statement would be those patients with a known/suspected germ-line predisposition to
 suffer multiple malignancies, such as, but not limited to Hereditary Breast and
 Ovarian Cancer Syndrome (BRCA1/2), Lynch syndrome or multiple endocrine neoplasia
 (MEN) syndrome.

 2. Patient with INR >1.5 and/or platelets ≤50.

 3. Patients with bleeding disorders.

 4. Patients on anti-platelet or anti-coagulation treatment that cannot be temporarily
 discontinued around the procedure.

 5. Patients who cannot give informed consent.

 6. Patients with known Hepatitis C viral infection.

 7. Patients with known Human Immunodeficiency Virus (HIV) infection.

 8. If clinically judged by the investigator that the patient should not participate in
 the study.