Major cancer update issued on new sensitive blood tests

Major cancer update issued on new sensitive blood tests The ultra-sensitive test finds hidden signs and scientists say it could help extend lives A groundbreaking blood test can identify even tiny traces of one of the most lethal forms of cancer. The highly sensitive test can detect hidden indicators of pancreatic cancer by searching for a crucial genetic mutation overlooked by conventional testing. US scientists say it could potentially prolong lives by enabling doctors to pinpoint patients whose illness is more likely to recur - even when scans look encouraging. They revealed that the innovative blood test targets KRAS - a genetic mutation responsible for over 90% of pancreatic cancers. The research team, from Northwestern University Feinberg School of Medicine, Chicago, gathered blood samples from patients with localised pancreatic cancer during treatment. At diagnosis, the sensitive test identified signs of cancer in 65% of patients, compared to 17% using the standard test. After chemotherapy and surgery, the sensitive test kept detecting residual cancer in most patients, while imaging didn't. The findings, published in the journal Clinical Cancer Research, emerge as a revolutionary new drug targeting KRAS is demonstrating significant survival benefits. Study senior author Professor Akhil Chawla said: "As we enter the era of KRAS-targeted therapies, having a screening tool that tracks the same mutation becomes increasingly important. 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." Pancreatic cancer ranks amongst the most lethal forms of the disease, even when caught before it has visibly spread. Many patients endure months of chemotherapy and surgery, yet their cancer frequently returns. Prof Chawla said: "In these patients, circulating tumour DNA levels are often extremely low and difficult to detect. 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." How Prof Chawla's study worked The study tracked 106 Northwestern Medicine patients with localised pancreatic cancer from the point of diagnosis through chemotherapy and surgery. Researchers gathered blood samples from participants before treatment, after chemotherapy and following surgery between October 2020 and October 2024. At the time of diagnosis, the study revealed that the more sensitive blood test, digital droplet PCR or ddPCR, identified signs of cancer in nearly four times as many patients as conventional next-generation sequencing tests (NGS), which are more widely used. Even after chemotherapy and surgery, ddPCR continued to detect cancer in the majority of patients, while NGS and standard testing did not. Following chemotherapy, ddPCR detected tumour KRAS DNA in 60% of patients, compared with just 5% for NGS. Following surgery, ddPCR identified tumour KRAS DNA in 56% of patients, compared with 9% for NGS. Prof Chawla said: "This suggests physicians may currently be missing residual disease in most patients using currently available testing approaches." The results demonstrated that more accurate detection led to improved prediction of survival outcomes. The most striking finding was the identification of a previously undetected group of high-risk patients whose cancer was missed by standard NGS but picked up by ddPCR. This group survived an average of 27 months following diagnosis, compared with 41 months amongst patients who tested negative on both assessments. Prof Chawla added: "NGS and ddPCR are blood tests - often called liquid biopsies - that search for traces of DNA shed by cancer cells into the bloodstream. "Detecting this tumour DNA provides an early sign that cancer is present or may return. Because these tests rely on a simple blood draw, they can be repeated over time without requiring invasive procedures."