Genetic testing could help men with advanced prostate cancer to receive precision treatments for the disease, researchers reported last night.
The research team from The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust, UK, say that testing prostate cancer patients for mutations in key DNA repair genes could identify those who may benefit from therapies that specifically target DNA repair weaknesses in cancer cells.
Writing in the New England Journal of Medicine, they describe how they used a saliva test to test the patients’ DNA, examining the DNA code of 20 genes known to have a role in DNA repair in 692 men with advanced prostate cancer.
It is the largest study of its kind to date and the first to comprehensively analyse germline mutations in men with advanced, or metastatic, prostate cancer.
The team, which included scientists at seven cancer centres in the USA, found that 12% of men had at least one germline mutation in a DNA repair gene. The most common defective gene was BRCA2, which was mutated in 5% of men.
Professor Johann de Bono, professor of experimental cancer medicine at The Institute of Cancer Research, London, and consultant oncologist at The Royal Marsden NHS Foundation Trust, who led the study in the UK, said their findings could have important implications for patients.
"Genetic testing for these mutations could identify men with advanced prostate cancer who may benefit from precision treatment,” he said.
“We could offer these men drugs such as PARP inhibitors, which are effective in patients with certain DNA repair mutations and are showing important anti-tumour activity in ongoing clinical trials.
"Where we find BRCA2 mutations, we could also offer genetic testing and counselling to relatives of the patient to consider how we can reduce their cancer risk. We also need to establish the impact of having DNA repair defects on survival in men with prostate cancer, and whether we can predict who will develop severe disease, so we can design new treatment strategies to cure this disease."
Professor Paul Workman, chief executive of The Institute of Cancer Research, London, said: "This valuable study has given us new insights into the causes of aggressive forms of prostate cancer that have spread round the body.
"There is huge diversity in prostate cancers from patient to patient – some men live for decades with localised tumours, while in others cancers develop rapidly and spread round the body. Genetic markers that can detect the patients at high risk are desperately needed to improve men’s survival chances."
New England Journal of Medicine 6 July 2016
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