Canadian researchers have developed a new genetic test to identify prostate cancer patients who are at highest risk of recurrence after surgery or radiotherapy.
By analyzing DNA from diagnostic biopsies of men who underwent either surgery or image-guided radiotherapy to treat their prostate cancer, the researchers came up with a test that can determine “with greater precision” which men will need extra treatment, such as chemotherapy, to ensure that the cancer is eradicated.
The findings were published online Tuesday in the Lancet Oncology journal.
“This genetic test could increase cure rates in intermediate- to high-risk men by preventing progression to this metastatic spread of prostate cancer,” Dr. Robert Bristow, a clinician-scientist at Princess Margaret Cancer Centre in Toronto, said in a news release.
The test is currently still in “research mode,” Bristow told The Canadian Press. The hope is that the test will be validated, approved by Health Canada and ready for use in five years.
Bristow is the co-lead of the study, along with Dr. Paul Boutros, an investigator at the Ontario Institute for Cancer Research.
Hypoxia, or low oxygen, is a known factor is the spread of prostate cancer. The newly developed test can identify the cancer’s oxygen content, as well as the tumour’s abnormal genetic characteristics to determine which patients are at greatest risk of their prostate cancer returning, the study says.
The study showed that, among patients whose tumours had low levels of genetic changes and low hypoxia, the cancer recurrence rate was lower than seven per cent after five years.
Men with high levels of genetic changes and high hypoxia had much worse outcomes. More than 50 per cent of those patients had a recurrence of cancer.
Researchers hope to use the test to improve prostate cancer cure rates by identifying high-risk patients and offering them personalized treatment.
The test is almost 80 per cent accurate and can make a determination in about three days. In their study, the researchers noted that current prognostic tools for localized prostate cancer are imprecise, with 30 to 50 per cent of patients seeing their cancer return after radiotherapy or surgery.
“The clinical potential is enormous for thousands of patients,” Bristow said in the news release.
“This is personalized cancer medicine to the hilt -- the ability to provide more targeted treatment to patients based on their unique cancer genetic fingerprint plus what’s going on in the cancer cell’s surrounding environment.”
The genetic test was used on 126 men who were treated with image-guided radiotherapy (IGRT), and the results were compared to two different groups of men whose tumours were removed surgically.
The test produced similar results in both groups, so the researchers concluded it could be used in patients who choose radiotherapy or surgery as their initial treatment.
Prostate cancer is the most common type of cancer diagnosed in men. An estimated 23,600 men in Canada will be diagnosed with prostate cancer this year and about 4,000 will die from the disease, according to Canadian Cancer Society projections.
With files from The Canadian Press
