Blood test spots multiple cancers without clear symptoms, study finds

Doctors have told health services to prepare for a new era of cancer screening after a study found a simple blood test could spot multiple cancer types in patients before they develop clear symptoms.

The Pathfinder study offered the blood test to more than 6,600 adults aged 50 and over, and detected dozens of new cases of disease. Many cancers were at an early stage and nearly three-quarters were forms not routinely screened for.

It is the first time results from the Galleri test, which looks for cancer DNA in the blood, have been returned to patients and their doctors, to guide cancer investigations and any necessary treatment.

In the Pathfinder study, 6,621 adults aged 50 and over were offered the Galleri blood test. For 6,529 volunteers, the test was negative, but it flagged a potential cancer in 92.

Further tests confirmed solid tumours or blood cancer in 35 people, or 1.4% of the study group. The test spotted two cancers in a woman who had breast and endometrial tumours.

The test identified 19 solid tumours in tissues such as the breast, liver, lung and colon, but it also spotted ovarian and pancreatic cancers, which are typically detected at a late stage and have poor survival rates.

The remaining cases were blood cancers. Out of the 36 cancers detected in total, 14 were early stage and 26 were forms of the disease not routinely screened for.

Further analyses found the blood test was negative for 99.1% of those who were cancer-free, meaning only a small proportion of healthy people wrongly received a positive result. About 38% of those who had a positive test turned out to have cancer.