Blood test could warn of return of skin cancer

UK scientists say they are closer to developing an 'early warning system' for the return of cancer in patients using a simple blood test.

A study in 161 patients with malignant melanoma found a blood test for specific gene mutations was predictive of which patients would relapse after surgery to remove their cancers.

'Being able to develop an early warning system that will predict if a cancer will return could make a real difference to patients,' said Professor Karen Vousden, Cancer Research UK's (CRUK's) chief scientist. 'If follow up research shows that this test can be used to inform treatment decisions and improve outlook, it could be a game-changer in our ability to deal with advanced skin cancer.'

The team led by scientists at the CRUK Manchester Institute and the Christie NHS Foundation looked for circulating tumour DNA (ctDNA) – shed by cancer cells – into the blood for two known mutations associated with skin cancer. They analysed blood samples taken after surgery for mutations in the genes BRAF and NRAS – linked to 70 percent of melanomas.

Patients who had ctDNA in their blood after surgery had a shorter time to relapse than those without any detectable levels of ctDNA, found the study. And patients with detectable ctDNA for either mutation were much less likely to be alive five years later, with 33 percent surviving, than those whose blood showed no tumour DNA of whom 65 percent were still alive.

'For some patients with advanced melanoma, their cancer will eventually return. We have no accurate tests to predict who these patients will be, so our findings are really encouraging,' said Professor Richard Marais, lead researcher and director of the CRUK institute, based at the University of Manchester. 'If we can use this tumour DNA test to accurately predict if cancer is going to come back, then it could help doctors decide which patients could benefit from new immunotherapies.'

The study was published in Annals of Oncology.