Blood test may give early warning of skin cancer relapse

A blood test may be able to sound early warning bells that patients with advanced melanoma skin cancer are relapsing, according to a study.

Scientists from the Cancer Research UK Manchester Institute studied the DNA shed by tumours into the bloodstream – called circulating tumour DNA – in blood samples from seven advanced melanoma patients at The Christie NHS Foundation Trust.

“Being able to track cancers in real time as they evolve following treatment has huge potential for the way we monitor cancers and intervene to stop them growing back.’ – Professor Peter Johnson, Cancer Research UK’s chief clinician
In this early work they found they could see whether a patient was relapsing by tracking levels of circulating tumour DNA. And they found that new mutations in genes like NRAS and PI3K appeared, possibly causing the relapse by allowing the tumour to become resistant to treatment.

Most melanoma patients respond to treatment at first but their cancer can become resistant within a year. It is hoped that these approaches will allow doctors to use circulating tumour DNA to tailor treatment for individual patients to get the best result.

Around 40 to 50 per cent of melanoma patients have a faulty BRAF gene and they can be treated with the targeted drugs vemurafenib or dabrafenib. But for many of these patients the treatments don’t work, or their tumours develop resistance after a relatively short time. When this happens these patients can be offered immunotherapy drugs including pembrolizumab, nivolumab and ipilimumab. Detecting this situation early could be key to improving their care and chances of survival. Cancer Research UK Manchester Institute