“Tissue is the Issue”: Circulating Tumor Cells in Pancreatic Cancer

Abstract

Pancreatic cancer (PCa) is the fourth most common cause of all cancer-related deaths in the USA. Currently, the overall median survival is less than 1 year and 5-year survival rate is about 5 % [1]. The poor outcome for PCa is largely due to the fact that the vast majority of patients (pts) are diagnosed at an advanced disease stage or with occult metastases that soon reveal themselves despite no clinical or radiographic clues. Therefore, early and accurate diagnosis is critical to appropriately risk stratify and intervene to improve the clinical outcomes of pts with PCa. Diagnostic modalities in current use include cross-sectional imaging and the use of the non-specific serum biomarker carbohydrate antigen 19-9 (CA-19-9) and occasionally carcinoembryonic antigen (CEA). Radiographic imaging of PCa can be challenging due to the potential absence of a discrete pancreatic mass or presence of alternate symptom etiologies including pancreatic inflammation. Even in the setting of an appropriate clinical context with supportive imaging and serum biomarkers, assurance of histological or cytological confirmation of PCa is directly related to adequate tissue acquisition [2]. Methodologies for pancreatic tissue acquisition are invasive, of relative low diagnostic yield, and associated with potential complications such as pancreatitis, bleeding, duodenal perforations, and infections [3]. Therefore, novel non-invasive or minimally invasive methods of accurate PCa cell acquisition represent a clinical unmet need. Progression of most solid cancers is associated with intravasation of cancer cells into the pt’s circulatory system with dissemination to metastatic sites. These circulating tumor cells (CTCs), measured by collection and detection of epithelial cells in the peripheral circulation, are known to be detectable in pts with solid tumors from early through advanced disease [4]. In addition to diagnostic sampling, CTCs have many potential clinical applications in the management of patients with solid tumors. These include, but are not limited to, risk stratification/prognostication, monitoring of response to therapy, characterizing the tumor’s molecular alterations, screening for early relapse, and other potential ways to personalize therapy [5–9]. In this brief report, we describe the successful isolation and molecular characterization of CTCs from a pt with PCa in whom traditional acquisition of tissue for diagnosis and management was unsuccessful despite multiple traditional attempts.