In a potential breakthrough for cancer treatment, scientists funded by Cancer Research UK have designed a blood test that could not only match up patients to the most suitable therapy but also track the tumour’s progress to assess whether treatment is effective.

The approach could give doctors ‘real-time’ information on the genetic make-up of a disease and how it is changing in response to treatment. 

This is the first time a blood test has been used in this way during clinical trials of targeted medicines, “proving that the technique can monitor cancer simply and quickly”, said the charity.

Scientists and clinicians from The Institute of Cancer Research and The Royal Marsden looked at blood samples from 39 cancer patients with different types of late-stage disease, using a test that filters out tumour DNA to analyse genetic faults. 

This information could then be used to first determine the most appropriate targeted cancer treatment, and then monitor how well the treatment is working, if the cancer is changing, and whether it is becoming resistant to therapy.

It could also be used to doctors identify patients who might be suitable for clinical trials of experimental cancer drugs.

“Tumours and the gene faults that drive them are unique and constantly evolving. It’s crucial that we understand these changes so doctors can choose the best treatments for each patient,” said study lead Johann de Bono, from ICR and The Royal Marsden.

“We need to do more research, but this approach could have a huge impact on how we make treatment decisions, also potentially making diagnosis and treatment quicker, cheaper and less invasive.”

The findings were published in the journal Clinical Cancer Research.