Primary tumors shed cancerous cells, known as circulating tumor cells (CTCs), into the blood. These have been widely studied as prognostic biomarkers for various cancers.
Director professor Irving Waxman from University of Chicago says that "we demonstrated that this method is potentially quite valuable as well as non-invasive, feasible and safe." "We had no complications related to portal vein blood acquisition," he added.
‘Access to circulating tumor cells may help doctors define the diagnosis and guide treatment for pancreatic cancer.’
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 tumor would flow into the portal vein and then get trapped by the narrow vessels in the liver. Hence, they would not reach the peripheral venous system.
CTCs from gastrointestinal tumors are rarely identified in the peripheral blood until the cancer is widely metastatic. To test this theory, the researchers 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 four of the 18 patients.
The findings could offer doctors a method to diagnose pancreatic cancer earlier in patients. "Access to circulating tumor cells may help us define the diagnosis and guide treatment," Waxman said.