A newly developed blood test shows promise for identifying residual pancreatic cancer cells that may be missed by standard imaging and sequencing methods, potentially benefiting patients undergoing treatment. The highly sensitive digital droplet PCR (ddPCR) test, developed by a team at Northwestern Medicine in Chicago, detected signs of cancer in nearly four times as many patients as conventional next-generation sequencing (NGS) tests.
Both ddPCR and NGS search for traces of DNA shed by cancer cells into the bloodstream. The new ddPCR test specifically looks for the KRAS genetic mutation, which drives more than 90 percent of pancreatic cancers. The study, published in Clinical Cancer Research, found that ddPCR continued to detect cancer in most patients even after chemotherapy and surgery, while NGS and standard testing did not.
This capability could help clinicians identify patients whose disease is more likely to return, even when scans appear normal. Early detection is critical for pancreatic cancer, a disease often referred to as a 'silent killer' due to its late diagnosis and limited treatment options. In the UK, approximately 11,500 people are diagnosed with pancreatic cancer annually.
Pancreatic cancer is notoriously difficult to diagnose and treat. Common symptoms include jaundice, reduced appetite, weight loss, fatigue, nausea, vomiting, diarrhea, and constipation. Due to late detection, only about 10 percent of patients live longer than five years after diagnosis, with more than half dying within three months of diagnosis.
The Northwestern Medicine study identified a group of high-risk patients whose cancer was missed by standard NGS testing, as detected by ddPCR. These patients had a median survival of 27 months post-diagnosis, compared to 41 months for patients who tested negative on both ddPCR and NGS.
Dr. Akhil Chawla, study senior author, noted that circulating tumor DNA levels can be extremely low and difficult to detect in patients whose cancer returns after surgery. "Many patients and families ask me, 'How do we know if the treatment is working?' This research is part of trying to answer that question more precisely," Chawla stated.
The development of this blood test follows recent advancements in treatment, such as the new therapy daraxonrasib, which targets the KRAS mutation. "As we enter the era of KRAS-targeted therapies, having a screening tool that tracks the same mutation becomes increasingly important," Chawla said. "That combination could fundamentally change how we identify high-risk patients, monitor microscopic disease, and potentially intervene earlier before recurrence becomes clinically visible, ultimately getting more patients to cure."