New Blood Test Screens for Over 50 Types of Cancer, Detecting Tumours in Asymptomatic Individuals
A recent trial conducted by researchers at New York’s Memorial Sloan Kettering Cancer Center has found that a blood test screening for more than 50 types of cancer can detect tumours in individuals who show no symptoms. The test, developed by the firm Grail, utilizes a single blood sample to search for fragments of cancerous DNA that circulate throughout the body when tumours break off.
The trial involved screening 6,662 individuals aged 50 or over who did not exhibit any signs of cancer. Out of this group, a positive result was given to 92 individuals, and 35 of them were subsequently diagnosed with cancer. While 57 individuals were mistakenly told they had the disease, 35 of the detected cases were diagnosed early, before any symptoms appeared.
Publishing their findings in the journal The Lancet, the researchers stated that the study offers early evidence of the feasibility of using blood testing to screen for multiple cancers with a single test. Furthermore, they noted that the test successfully detected cancer types for which there are currently no screening tests available, including some that were in early stages. Detecting tumours before symptoms manifest presents the opportunity for earlier treatment, thereby increasing the chances of survival.
In the UK alone, more than 375,000 cancers are diagnosed annually, resulting in 167,000 deaths each year. However, experts have raised concerns about the potential negative impacts on mental health when individuals are informed they have cancer when they do not. Additionally, the additional testing required may strain the National Health Service (NHS).
Dr Richard Lee, a cancer doctor at the Royal Marsden in London who was not involved in the study, emphasized the importance of considering the psychological effects and potential harm of false-positive results. He cautioned against allowing the exciting data from the study to overshadow these concerns.
Grail’s blood test has been the subject of years of research, as the early detection of tumours is vital in reducing deaths from cancer. A separate trial conducted by Oxford University earlier this year found that the screening successfully detects cancer in the blood of two-thirds of individuals who present with symptoms. The study, which examined 5,461 patients in NHS hospitals in England and Wales, detected cancer in 244 out of 368 individuals who had the disease. It demonstrated greater accuracy in individuals who already experienced pain or lumps, correctly providing a negative result for 98% of people without cancer, thereby saving them from the worry and inconvenience of further tests.