New test may improve diagnosis and treatment of pancreatobiliary and other gastrointestinal cancers

By collecting samples from the portal vein — which carries blood from the gastrointestinal tract, including from the pancreas, to the liver — physicians can learn far more about a patient’s pancreatic cancer than by relying on peripheral blood from a more easily accessed vein in the arm.

Primary tumours shed cancerous cells, known as circulating tumour cells (CTCs), into the blood. These have been widely studied as prognostic biomarkers for various cancers. Because these cells are often larger, irregularly shaped and tend to cluster together, they get trapped in smaller vessels.

The authors hypothesized that most cells released from a gastrointestinal tumour would flow into the portal vein and then get sequestered by the narrow vessels in the liver. These cells would not reach the peripheral venous system. CTCs from gastrointestinal tumours are rarely identified in the peripheral blood until the cancer is widely metastatic.

To test this theory, researchers from the University of Chicago used an ultrasound-guided endoscope and a small needle to take blood from the portal vein during routine diagnostic endoscopies. They found CTCs in 100 percent of 18 patients with suspected tumours in the pancreas and bile ducts. Tests using peripheral blood samples, the standard method, detected tumours cells in only 4 of the 18 patients.

To test this theory, researchers from the University of Chicago used an ultrasound-guided endoscope and a small needle to take blood from the portal vein during routine diagnostic endoscopies. They found CTCs in 100 percent of 18 patients with suspected tumors in the pancreas and bile ducts. Tests using peripheral blood samples, the standard method, detected tumors cells in only 4 of the 18 patients.
‘We demonstrated that this method is potentially quite valuable as well as non-invasive, feasible and safe,’ said study director Irving Waxman, MD, professor of medicine and surgery and director of the Center for Endoscopic Research and Therapeutics at the University. ‘We had no complications related to portal vein blood acquisition.’ University of Chicago