In the recent years, scientists have known that tumors can shed cancerous cells from the primary site into the patient’s bloodstream. They call these circulating tumor cells (CTCs), and have leveraged CTC’s presence to create detection methods for a wide range of cancers. Currently, the detection method for pancreatic cancer relies on blood taken from traditional arm venipunctures. However, researchers at the University of Chicago have challenged the sensitivity of this method.
The researchers reasoned that because of the large and irregular shape of CTCs, these cells can get trapped in small vessels before showing up in the bloodstream. So they devised a collection method where blood was taken from the portal vein, the main vessel that drains blood from the gastrointestinal tract and spleen to the liver. Compared to blood taken from the arm, portal vein blood showed much higher sensitivity at detecting tumor cell counts.
In 18 patients with suspected tumors in the pancreas and bile ducts, portal vein sampling detected CTCs for all 100% of patients. In contrast, tumor cells were only detected for 22% of patients with the traditional peripheral blood sampling method. Additionally, they found that the portal vein contained an abundance of CTCs for all cancer stages, including the hard-to-detect early stages. For every 7.5 milliliters of blood, more than 100 tumor cells were detected with portal vein blood samples, compared ~ 1 tumor cell for peripheral blood samples."This is a novel and far more sensitive way to acquire, enumerate, and characterize CTCs from pancreatobiliary and other gastrointestinal cancers in this setting.” Dr. Irving Waxman, senior study author.
This new sampling method will be especially beneficial for early diagnosis of pancreatic cancer. According to the National Cancer Institute, the five-year survival rate for pancreatic cancer is only 7.2%. The disease is so deadly because signs and symptoms don’t appear until the cancer is quite advanced. By such point, the cancer has likely metastasized and surgical removal is not effective. However, with this method, the cancer can be detected early enough where removal is still possible.
"In the setting of localized cancer where these findings are most applicable, the additional information of portal vein CTC number and their molecular characterization may help predict who will benefit from aggressive therapy before surgery, who is most at risk for a recurrence after the operation, and even who will not benefit from surgery at all." Dr. Daniel Catenacci, co-first author of the study.
Watch the video to learn more about pancreatic cancer.
Sources: Gastroenterology, Science Daily