A new blood test could predict which men with advanced prostate cancer will respond to new targeted treatments for the disease.
Researchers were able to detect tumour DNA in men’s blood and pick out cancers with multiple copies of the androgen receptor gene, which many prostate cancers rely on to grow.
Men with multiple copies of the gene responded much less well than otherwise to the targeted therapies abiraterone and enzalutamide – now standard treatment for advanced prostate cancer.
These men could be spared treatments that are unlikely to work for them, and doctors could offer them alternative options instead.
The test will have to be assessed further in clinical trials, but the researchers say that it costs less than £50 and could be used in clinical practice to personalise treatment.
A team at the Institute of Cancer Research, London, and the Royal Marsden NHS Foundation Trust, along with colleagues in Europe, analysed blood samples from 265 men with advanced prostate cancer who were being treated with abiraterone or enzalutamide, either before or after docetaxel chemotherapy.
The study is published in the journal, Annals of Oncology, and was funded by Prostate Cancer UK, with support from the Movember Foundation, Cancer Research UK, and the NIHR Biomedical Research Centre at The Royal Marsden NHS Foundation Trust and the Institute of Cancer Research (ICR).
Researchers took samples 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 in whom a 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 study included both patients who had previously received chemotherapy and 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.
The androgen receptor is known to play an important role in helping cancers to become resistant to treatment with abiraterone and enzalutamide, which are standard treatments for men whose cancer is resistant to traditional hormone blocking therapy and has spread round the body.