A pioneering blood test capable of detecting more than 50 types of cancer before symptoms manifest could save tens of thousands of lives annually, according to promising new research. Results from an NHS-backed trial indicate that the Galleri test—often described as the 'Holy Grail' for cancer—flags four times as many cancers when integrated with existing screening programmes. In practice, this could prevent one in five late-stage diagnoses, a major contributor to the 170,000 cancer deaths each year in the UK.
Potential Impact on Survival
Doctors involved in the trial assert that the potential impact on survival is enormous, with up to 30,000 lives saved every year. The test, manufactured by American pharmaceutical firm Grail, detects fragments of cancerous DNA that have broken off from tumours and are circulating in the blood. This 'signal' enables physicians to identify traces of the disease months or even years before symptoms appear, when cancer is most treatable.
Trial Details and Results
Launched by the NHS in 2021, the trial involved testing more than 142,000 adults aged 50 to 77. Nearly one in 100 participants received a positive result over three tests, and in 52 per cent of these cases, cancer was later confirmed. The trial also observed a 25 per cent reduction in cancers first detected in A&E departments, where patients are often severely unwell—a strong predictor of poor survival. Doctors believe this shift alone could transform outcomes for thousands of patients.
Presenting the results ahead of the American Society of Clinical Oncology (ASCO) annual meeting, Sir Harpal Kumar, Chief Scientific Officer of Global Clinical and Medical Affairs at GRAIL, described the findings as 'extremely important'. He added: 'Galleri represents a potential transformational shift in cancer detection, moving us to a more comprehensive and proactive approach where doctors can offer treatment and not just end-of-life care—that is the difference.'
Reducing False Positives
The test is also expected to reduce the number of false positives from current screening programmes, such as those for breast, bowel, and cervical cancers. An estimated three million people in the UK undergo urgent investigations annually due to symptoms that might indicate cancer, yet only six per cent receive a diagnosis. Sir Kumar noted: 'If we had a test that was far more predictive, we would be able to use some of that diagnostic capacity where it would deliver greater benefit.'
Criticism and New Findings
Earlier this year, the trial faced criticism for not meeting an endpoint of reducing stage 3 and 4 cancers, where the disease has spread. However, newly published results tell a different story. For certain cancers, the test showed particularly promising outcomes. Stage 4 oesophageal cancer diagnoses fell by more than 57 per cent among those offered the test, and stage 4 bowel cancer diagnoses were reduced by over a third. In England, the survival rate for bowel cancer diagnosed at stage 4 is just 11 per cent, compared to 64 per cent for stage 3.
Sir Kumar conceded: 'We did see a substantial decrease in stage 4 cancers, but this was outweighed by an overall increase in the number of stage 3 cancers picked up.' He explained that the test can detect cancers for which no screening programmes currently exist, such as pancreatic, ovarian, liver, oesophageal, and bladder cancers. He added: 'The trial has revealed just how much undiagnosed stage 3 cancer is already prevalent in the population before any screening commences.'
Future Prospects
Dr Thomas Round, a GP at Bromley by Bow Health Centre and academic at King's College London, described the test as 'potentially game-changing'. He emphasized: 'The reduction in the number of patients diagnosed with cancer after A&E activity is really important from an NHS viewpoint. The test would also fit very well into the NHS because we have existing pathways that we can utilise. But we need more investment in diagnostics—from hospital to community and from analogue to digital.'
Professor Peter Johnson, National Clinical Director for Cancer at NHS England, stated: 'Finding cancers at an earlier stage is central to the National Cancer Plan. The NHS will explore every opportunity to detect more cancers sooner and save more lives. We look forward to seeing the data from the trial in detail, to help us make decisions on what this could mean for the NHS in the future.'
Personal Story: Jan Kitching
Jan Kitching, 69, from Gateshead, an active grandmother and full-time carer, had no reason to suspect she had cancer. When her GP practice invited her to join the trial, she readily agreed. Her first two tests were clear, but on 2 May 2024, the day before her 67th birthday, she received a call indicating a possible colorectal cancer signal. 'I just couldn't believe it,' she said. 'I had no symptoms, a negative stool test just months before, and no family history.' Within two weeks, she underwent a colonoscopy, which confirmed stage 2 bowel cancer. On 17 June, she had surgery to remove the tumour, which had not spread. Two weeks later, she was back caring for her father and grandchildren, cancer-free. She believes the test saved her life: 'I dread to think what would have happened without that test. I had no warning signs at all. Without the blood test, the cancer could easily have progressed, and I might not be here.'
