New blood test identifies which subtypes of pancreatic cancer respond to treatment

November 2020 Clinical Practice Tobias Rawson
Pancreatic cancer, malignant tumor of pancreas, 3D illustration

A new blood test to distinguish between pancreatic cancer subtypes has been developed, potentially changing the way physicians diagnose the disease. Subtyping, such as this, marks a departure from ‘blanket’ treatment strategies, allowing for a personalised treatment approach. Using this test, physicians will be able to select which pancreatic cancer subtypes will benefit most from a particular treatment regimen, and those that won’t, thereby sparing ineligible patients from the unnecessary risk of a treatment’s side effects. With the rising costs of cancer medications, this test may also offer a cost-effective approach to oncology patient management.

Recently published in Clinical Cancer Research, a journal from the American Association for Cancer Research, the test measures the plasma concentration of a glycan sugar called sTRA, which is produced by a subtype of pancreatic cancer. This particular subtype does not typically respond to chemotherapy, and so identification of this subtype would spare patients from unnecessary treatment that they would not benefit from.

Best decisions possible

“Knowing which type of pancreatic cancer a person has is critical to implementing the right treatment strategy for each patient”, explains Dr. Brian Haab, a corresponding author of the study, and professor at the Van Andel Institute, located in Grand Rapids, Michigan. “We hope that our new test, which detects a marker produced by cancer cells of one subtype and not the other, will one day soon be a powerful tool to help physicians and patients make the best decisions possible.”

This new sTRA test builds upon a previous diagnostic test from Haab et al., published in 2019. Detecting another sugar called CA19-9, this test was combined with sTRA to detect nearly 70% of pancreatic cancers with less than a 5% false-positive rate.

“The 2019 combination test tells us whether there is cancer and the new sTRA test helps us determine what kind of pancreatic cancer, which then could allow physicians to better narrow down the appropriate treatment plan,” Haab explains “When used in sequence, we believe the combination test and the new sTRA test could help catch and identify pancreatic cancer more quickly and definitively.”

Poor prognosis

Pancreatic cancer carries a notoriously poor prognosis, due to the fact that symptoms do not typically become obvious until a late stage of disease. With an incidence rate of 13 per 100,000, 2,024 cases of pancreatic cancer were diagnosed in Belgium, in 2018. Furthermore, at least 46.5% of cases presented with stage IV disease at time of diagnosis. This prevalence of late-stage disease is reflected in the 5 year survival rate; just 11.2% and 11.9% in Belgian men and women, respectively. These statistics can be explained not only due to the aggressive nature of pancreatic cancer, but also because curative surgery and chemotherapy is only possible in 10-15% of patients.

The implementation of this new test into standard clinical practice has the potential to have a positive impact on these prognostic statistics, as physicians currently have no way to select which pancreatic cancer subtypes will respond to existing chemotherapy regimens. With better selection tools, physicians will be able to decide which treatment options are best suited for each individual patient. Both combination and new sTRA tests are expected to undergo further clinical validation.