The team also found that patients with the BRCA2 gene mutation have a higher likelihood of tumour spread. These results could be used to provide more intensive treatment to patients with aggressive prostate cancer.
'This information gives us new precision about the treatment response of men with prostate cancer, and important clues as to how to better treat one set of men versus the other to improve cure rates overall,' said Professor Robert Bristow of the University of Toronto, who led the team.
Prostate cancer can be cured with radiotherapy or surgery, but up to 30 percent of men develop a more aggressive form of the disease following treatment. The researchers studied tumours from 500 Canadian men who had had localised, non-inherited prostate cancer that had been treated with surgery or radiotherapy.
'We used specialised state-of-the-art DNA sequencing techniques to focus on the genetics of prostate cancers to better understand what is so different from one man's disease to another man's disease,' said Professor Bristow.
They were able to identify a set of genetic differences between patients who are likely to respond well to surgery or radiotherapy, and in patients whose cancer is likely to spread.
A related study focused on 14 men with the BRCA2 mutation from the 500 patients, in collaboration with co-principal investigators Dr Paul Boutros of the Ontario Institute for Cancer Research and Professor Gail Risbridger of Monash University, Australia. The researchers found that the tumours of these patients contained genetic changes associated with cancer spread and resistance to hormone therapy. Just 50 percent of these patients survive five years after diagnosis, compared with a usual survival rate of 80 percent in prostate cancer patients.
'We knew that patients who had a mutation in the BRCA2 gene had increased death rates from prostate cancer but no one had studied them because they're so rare,' Dr Bristow, told Global News. Around two percent of men with prostate cancer have a BRCA2 mutation.
The researchers plan to test 500 more patients over the next two to three years.
'This is an exciting time in prostate cancer research in which the genetics of individual men and their cancers are beginning to dictate precise and customised treatment,' said Dr Bristow.