A Blood Test Caught Stage 1 and 2 Pancreatic Cancer 87% of the Time in 1,800 Patients on Three Continents, With a 3% False-Positive Rate in Low-Risk People. It Also Flagged 'Stage 0' Precancer Two-Thirds of the Time.

An experimental blood test developed at City of Hope correctly identified stage 1 and stage 2 pancreatic cancer 87% of the time in a study of nearly 1,800 patients across the United States, Europe and Asia, researchers reported Wednesday in Nature Medicine, a result that puts a reliable early screen for one of the deadliest cancers within sight for the first time.

Pancreatic cancer has the worst survival rate of any major cancer. Just 14% of patients are alive five years after diagnosis, and the main reason is timing: about 90% of tumors are found only after they have spread, when surgery is no longer an option. There is no routine screening test, and the imaging used to monitor high-risk patients is invasive, expensive and only modestly effective at catching the disease early.

The test, called PANXEON, takes a different approach from earlier liquid biopsies, which typically looked for a single marker. It measures three at once: microRNAs circulating freely in the blood, microRNAs packaged inside tiny cell-derived bubbles called exosomes, and CA19-9, a protein that has been used for decades to track pancreatic tumors but is too unreliable on its own to screen with. An artificial intelligence model then combines the three readings into a single risk score. City of Hope says it is the first investigational test to fold all three into one assay.

"Most biomarkers tell you one part of the story," said Ajay Goel, chair of the Department of Molecular Diagnostics and Experimental Therapeutics at City of Hope and the study's senior author. "Combining multiple biological signals gives us a clearer picture of what may be happening in the pancreas."

The false-positive rate was 3% in low-risk groups and 16% in high-risk groups, the latter a number Goel's team and outside experts both flag as needing work. Notably, the study did not test PANXEON only against healthy volunteers, the easy comparison that has flattered earlier tests. It was evaluated in people with inherited genetic risk, pancreatic cysts and chronic pancreatitis, the patients who would actually be screened, and whose conditions are the most likely to confuse a blood marker.

That design produced the study's second headline result. PANXEON detected high-grade dysplasia, an advanced precancerous change in the pancreas often called "stage 0" cancer, more than 64% of the time in patients with high-risk cysts. Pancreatic cysts are common and most never turn malignant; doctors currently have no good way to tell which ones need surgery and which can be watched. A blood test that can sort them would let surgeons intervene before invasive cancer ever forms.

"Pancreatic cancer remains so deadly largely because we find it after the window for cure has begun to close," Goel said. "For patients, these findings represent progress toward finding pancreatic cancer before symptoms appear and while more treatment options remain available." He stressed that PANXEON is meant to identify who needs further evaluation, not to replace imaging or biopsy. "A stage shift is not just a statistic. The earlier we find pancreatic cancer, the greater the chance that meaningful intervention is still possible."

Kyaw Lwin Aung, a medical oncologist not involved in the work, told Scientific American that the test's sensitivity for early detection is "very promising, but the assay's specificity still needs improvement for high-risk groups." Larger trials are required before PANXEON can be used in clinics, and the researchers say validating the result in more patients is the next step. The paper, "Liquid biopsy for early detection of pancreatic ductal adenocarcinoma," was published alongside news of the FDA's approval of daraxonrasib for late-stage disease, a reminder of how much of the field's progress has come at the wrong end of the timeline.