New hope for skin cancer patients after scientists develop simple blood test for determining best possible treatment

A new blood test is being developed to help doctors work out the best treatment for skin cancer patients.

The test, known as liquid biopsy, is currently at trial stage, but it is hoped that in the future it will be used regularly to aid doctors in making crucial decisions about when to start and stop different treatments for patients with advanced melanoma.

The usual way to check how well cancer treatments are working is via a CT scan, which provides detailed pictures of the inside of the body, and melanoma patients have these every few months. The scan helps doctors spot if a tumour has shrunk, grown or if the cancer has spread to other parts of the body.

However, they are time-consuming, need numerous staff and require patients to spend up to half a day in hospital. The new test may offer a far simpler option.

The new blood test looks for circulating fragments of cancer DNA. Lower levels mean the cancer is shrinking and the treatment is working. A higher level shows that treatment isn’t working

It looks for circulating fragments of cancer DNA. Lower levels mean the cancer is shrinking and the treatment is working. A higher level shows that treatment isn’t working.

Results can be provided within days, meaning that the test can track changes in how treatment is working in real time, say doctors. And, as it’s just a blood test, it can be carried out regularly.

The test focuses on how well melanoma immunotherapy drugs nivolumab and ipilimumab are working. These help the immune system seek out and destroy cancer. It can also tell doctors if patients are responding well to dabrafenib and trametinib, which are targeted therapies that interfere with the way certain cancers grow and survive.

These treatments are highly effective, but they don’t work for everyone. And the targeted therapies can stop working suddenly, without warning.

Having a test that can be carried out consistently will mean that doctors will be able to pick up any changes and switch treatment without delay, giving patients the best possible chance.

Professor Paul Lorigan, consultant oncologist at The Christie NHS Foundation Trust in Manchester, who led a recent study into the test, said: ‘We have been using this blood test in real time to identify the best treatment strategy for patients and when to switch to another therapy.

‘I hope in the future analysing the tiny pieces of DNA coming from the cancer found in the patient’s bloodstream could be commonly used to tell us when a patient is responding to treatment, and when’s the optimum time to change to a new therapy.’