A blood test could help predict which advanced prostate cancer patients are likely to do best when treated with certain targeted treatments, according to new UK research.
The test, developed by scientists at The Institute of Cancer Research (ICR) and Royal Marsden NHS Foundation Trust, detects DNA released by cancer cells into the bloodstream.
Men whose blood samples carried multiple copies of a particular gene tended to do worse when treated with the drugs abiraterone (Zytiga) and enzalutamide (Xtandi) – the standard treatment for advanced prostate cancer.
The blood test will now need to be developed further in clinical trials, said the researchers. But they believe it could one day be used to personalise treatment for men with advanced prostate cancer.
Details of the test, published in the journal Annals of Oncology, show it can detect cases where prostate cancer cells carry multiple copies of the androgen receptor gene, which many prostate cancers rely on to grow.
Researchers analysed blood samples from men with advanced prostate cancer on three different clinical trials, taking samples before receiving abiraterone or enzalutamide, and after the disease progressed.
In an initial group of 171 patients, men with high levels of the gene in their blood samples were four times more likely to die over the course of the study than those with lower levels. The findings were confirmed in a second study of 94 men.
The researchers believe that identifying the patients who may not benefit from these treatments could spare them unnecessary treatment and side effects, and doctors could possibly offer alternative options.
Dr Gerhardt Attard, who led the study at the ICR, said that while abiraterone and enzalutamide are both “excellent treatments” for advanced prostate cancer, they don’t work for everyone and the disease can rapidly return.
“There is no approved test to help doctors choose whether these are the best treatments for an individual,” he added. The team believes their blood test could help provide some of those answers, and Attard said they will now look to test it further in clinical trials.
Dr Emma Smith, science information manager at Cancer Research UK, said: “Developing tests that help doctors predict how likely a treatment is to work will prevent patients from suffering unnecessary side effects from treatments that are unlikely to benefit them.
“If further studies confirm this test is reliable, it could also help doctors choose better options for men whose prostate cancer is unlikely to respond to standard treatments.”
The study 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 and ICR.
Conteduca, V., et al. (2017). 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. DOI: 10.1093/annonc/mdx155