A new experimental blood test has delivered encouraging results with sensitive detection of pancreatic cancer at the earliest stage which has been one of its key challenges. The test, termed the PANXEON, was tested in a large international trial and was able to diagnose many stage I and II pancreatic cancers from just a blood. It was published in Nature Medicine from 16 th September.
Pancreatic ductal adenocarcinoma (PDAC) is by far the most common form of pancreatic cancer. It has a high mortality rate due to the challenges in detecting the early disease. This is a silent disease, with no significant early symptoms, or silent disease in which symptoms have a latency period. At present, there is no screening test for early pancreatic cancer that is in widespread use, which is an important avenue for research.
PANXEON consists of a collection of microRNA markers and carbohydrate antigen 19-9, or CA19-9. While microRNAs regulate gene activity, CA19-9 is a previously-used protein marker in pancreatic cancer management. The combination was created to enhance the characterization of cancer vs. benign.
This global study investigated 1785 subjects with and without pancreatic ductal adenocarcinoma from four countries. The authors designed and validated a microRNA signature first, and then validated it integrated with CA19-9 to compose the PANXEON score. Sensitivities of stage I+II pancreatic cancer detection were 86.8% on the testing cohort. The false-positive rate was listed as 3.2% in screening low-risk controls, and 15.6% in screening high-risk controls.
The study further concluded that PANXEON could detect for high-grade dysplasia from in individuals with high-risk pancreatic cysts. This means PanXEON could present doctors with an opportunity for investigation and intervention before invasive cancer occurs, as high-grade dysplasia can be a preneoplastic abnormality. The study achieved this in 64.3% of high-risk incident cases.
A different and perhaps more fascinating discovery was made with a smaller cohort of patients being followed throughout treatment. Levels of the microRNA signature were lowered with neoadjuvant chemotherapy and post-surgery, then increased with disease recurrence. Researchers claimed that this opens up the door for such blood based markers potentially being usable in applications other than early detection; though a great deal more research is necessary to make this a reality.
These findings further contribute to the increasing research into blood-based detection of pancreatic cancer. A blood panel with four markers providing an earlier test was described in 2006 by NIH supported researchers using ANPEP, PIGR and CA 199, and THBS2. It was able to separate 91.9% of pancreatic cancer patients from controls for all stages, and 87.5% of all study stage I/II cancers.
While these results are promising, PANXEON is not currently a routine screening test. The team conducting the research notes that prospective testing in larger populations will be needed to show that it is useful in the real world months or even years before symptoms occur. This is a key distinction as a marker is only considered useful as a screening test if it proves to be reliable, safe, and clinically useful.
