A new blood test costing under £50 could predict which men with advanced prostate cancer will benefit from targeted treatments, researchers reported last night.
Working with scientists in Europe, researchers from The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust, were able to detect tumour DNA in men’s blood and pick out cancers with multiple copies of the androgen receptor gene.
Writing in the Annals of Oncology, the team said that men with multiple copies of the gene did not respond as well to abiraterone and enzalutamide, which are standard treatments for advanced prostate cancer.
This discovery could lead to these men being offered alternative options that are more likely to work.
The research team analysed blood samples from 265 men with advanced prostate cancer, all of whom were being treated with abiraterone or enzalutamide, either before or after docetaxel chemotherapy.
Samples were taken from patients on three different clinical trials, both before receiving abiraterone or enzalutamide, and again after their disease began to progress.
In the primary trial of 171 patients, men whose blood test detected multiple copies of the gene that carries the instructions for making the androgen receptor were four times more likely to die over the course of the study than those who did not.
The findings were confirmed in a second group of 94 patients, where men with multiple copies had an eight-fold shorter response to treatment than men with one or two copies of the gene.
Dr Gerhardt Attard, of the Centre for Evolution and Cancer at The Institute of Cancer Research, London, and consultant medical oncologist at The Royal Marsden NHS Foundation Trust, said: "Abiraterone and enzalutamide are excellent treatments for advanced prostate cancer and some men can take these drugs for years without seeing a return of their cancer.
“But in other men, these drugs do not work well and the disease rapidly returns. Currently there is no approved test to help doctors choose whether these are the best treatments for an individual.
"We have developed a robust test that can be used in the clinic to pick out which men with advanced prostate cancer are likely to respond to abiraterone and enzalutamide, and which men might need alternative treatments.
"Our method costs less than £50, is quick to provide results, and can be implemented in hospital laboratories across the NHS. We are now looking to assess our test in prospective clinical trials and would hope it can become part of standard patient care."
Dr Iain Frame, director of research at Prostate Cancer UK, added: "To stop prostate cancer from being a killer, we need to move away from a one-size-fits-all approach to treatment. This test could be a significant step towards that and we’ll be watching its development very closely."
Conteduca V, Wetterskog D, Sharabiani MTA et al. Androgen receptor gene status in plasma DNA associates with worse outcome on enzalutamide or abiraterone for castration-resistant prostate cancer: a multi-institution correlative biomarker study. Annals of Oncology May 2017; doi:10.1093/annonc/mdx155
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