A blood test that searches for tiny fragments of tumours could predict which lung cancer patients need more intensive treatment.
The NeXT Personal test can detect one part per million of circulating tumour DNA (ctDNA) in the body.
Scientists at the Francis Crick Institute and UCL trialled it on samples from 171 patients with early-stage lung cancer.
Those with low levels of ctDNA were less likely to relapse and had higher overall survival rates, the study found.
James Black, a postdoctoral clinical fellow at the Crick and UCL, said: “We’ve shown that the presence or absence of tumour DNA in the blood was strongly predictive of prognosis.
“ctDNA testing, especially using ultrasensitive platforms, could help clinicians make more informed decisions about treatment and give patients a more accurate idea of how their disease might progress.
“More research to validate these tests will help to get them on the agenda for regular clinical use.”
Early-stage lung cancer is usually treated by removing the tumour via surgery and with chemotherapy or immunotherapy, depending on the stage.
The team now plans to use the test, developed by Peronalis, on samples from patients who have undergone surgery.
If it is able to accurately predict which will relapse, it could help doctors decide who should be offered additional therapy to increase their chances of being cured.
Professor Charles Swanton, a leading medical oncologist working at the Crick and University College London Hospitals, said: “Lung cancer is one of the most common types of cancer in the UK, but it’s hard to treat with a high relapse rate.
“It’s vital to understand who would benefit from more aggressive treatment, especially for patients with stage one disease who are often diagnosed during CT screening for those at a higher risk.
“Using sensitive ctDNA tests is one way to do this, which we hope will maximise clinical benefit and minimise unnecessary treatment for individual patients.”
Marianne Baker, research information manager at Cancer Research UK, said this kind of test “can help us move toward an age of personalised medicine, ensuring clinicians can get the right treatment to the right people by accurately sorting them into groups based on what their disease is likely to do”.
She added: “The test can help to improve quality of life and survival by ensuring clinicians can go all-in for people whose disease is more likely to come back after treatment, while sparing people difficult treatments they might not need if their disease is less risky.
“More research is needed, but the study takes us a step closer to a day where treatments can be tailored to patients.” The findings were published in the journal Nature Medicine.