New Blood Test Shows High Accuracy for Early Pancreatic Cancer Detection

A new blood test could change the outlook for one of the deadliest cancers—pancreatic cancer—by catching it much earlier than ever before. Researchers identified two previously unknown proteins in the blood that, when combined with existing markers, dramatically improved detection accuracy. The four-marker test was able to spot pancreatic cancer in over 90% of cases and performed especially well even in early stages, when treatment has the best chance of success.

Researchers supported by the National Institutes of Health have created a new blood test designed to identify pancreatic ductal adenocarcinoma, one of the most lethal types of cancer. Because pancreatic cancer is often discovered only after it has advanced, treatment options are limited and survival rates remain low. This new approach, detailed in Clinical Cancer Research, could help detect the disease sooner and improve patient outcomes.

Pancreatic cancer has a poor prognosis, with only about 10% of patients living longer than five years after diagnosis. However, doctors believe survival could improve significantly if the disease is caught earlier, when treatment is more effective. Despite this, there are currently no reliable screening tools available to detect pancreatic cancer in its early stages.

Scientists from the University of Pennsylvania Perelman School of Medicine and Mayo Clinic analyzed blood samples from individuals with and without pancreatic cancer. They evaluated several biomarkers, including carbohydrate antigen 19-9 (CA19-9), commonly used to monitor treatment response, and thrombospondin 2 (THBS2), another previously studied marker. Individually, these markers have limitations—CA19-9 levels can rise in non-cancerous conditions like pancreatitis or bile duct obstruction, and some people do not produce the marker at all due to genetic differences.

By examining stored blood samples, the researchers identified two additional proteins that appear to be elevated in people with early-stage pancreatic cancer: aminopeptidase N (ANPEP) and polymeric immunoglobin receptor (PIGR). These newly identified biomarkers showed clear differences between cancer patients and healthy individuals.

When combined with CA19-9 and THBS2, the four-marker panel demonstrated strong performance. It correctly distinguished pancreatic cancer cases from non-cases 91.9% of the time across all stages, with a false positive rate of 5% in non-cases. For early-stage (stage I/II) cancer, the test detected 87.5% of cases. An important advantage of the test is its ability to differentiate pancreatic cancer from other non-cancerous pancreatic conditions, including pancreatitis, which helps reduce the risk of misdiagnosis and unnecessary concern for patients.

The study findings warrant further testing in larger populations, particularly in people before they show symptoms. Such "prediagnostic" studies would help determine if the test could be used as a screening tool for people at high risk of developing the disease based on family history, genetic screening results or personal history of pancreatic cysts or pancreatitis.

While this specific test shows promise for pancreatic cancer, researchers note that currently we can't reliably diagnose most cancers using a blood test. One major reason is it's often difficult to distinguish between cancer cells and normal, healthy cells, especially with early-stage tumours. Blood tests can give clues about whether certain cancers are present by revealing abnormalities in blood cell counts, identifying tumour markers like prostate-specific antigen, or locating circulating tumour cells that break off from original tumours.

Liquid biopsies represent a cutting-edge approach to cancer detection, using blood samples to pick up the smallest signs of cancer swirling through the blood. These tests analyze circulating tumour DNA (ctDNA)—fragments of tumour DNA that enter our blood from cancer cells. Liquid biopsies can be used to diagnose cancer, guide personalised treatment, check if any traces of cancer remain after therapy, and track changes as tumours evolve. They are much less invasive than surgical biopsies and can reveal what's happening in the body in much more detail than scans.