Dr. Zlotta is researching ways to help improve detection of the aggressive and life-threatening forms of the disease. Dr. Zlotta is an internationally renowned surgeon who specializes in treating cancers of the bladder and prostate. He is Director of Uro-oncology at Mount Sinai Hospital and a professor in the Department of Surgery in the University of Toronto’s Faculty of Medicine.
According to statistics, 1 in 7 Canadian men will be diagnosed with prostate cancer in their lifetimes. But a diagnosis of prostate cancer can mean very different things and have a different prognosis depending on the type. Can you tell us a little bit about more about this?
We know that about two to three per cent of patients diagnosed with prostate cancer die from the disease. This is a very high number of men and is a major public health issue. However, most men die with, rather than from prostate cancer.
We published a landmark study in 2013 that showed that a lot of men–about 50 to 60 per cent of the men in our study—died with prostate cancer cells in their prostate rather than from prostate cancer. Our findings showed that the number of non-life-threatening cancers out there is larger than we thought. This research points to an urgent need for improved prostate cancer screening strategies. We need to be able to accurately identify men with the aggressive and life-threatening form of prostate cancer vs. those cancers that will never threaten a man’s life.
What about the PSA test that’s commonly used?
The test works by measuring the level of a protein called Prostate Specific Antigen (PSA) in the blood. PSA levels may be elevated in several diseases of the prostate—including, but not exclusively, cancer. PSA blood tests do help detect tumours earlier and are connected with an improved survival rate for prostate cancer—although small. The issue we face with the PSA screening test is that it comes with a steep cost of potentially diagnosing and treating a huge number of cancers that would never have needed treatment. With treatment, there’s always the potential for complications. And it’s also important to think about the psychological impact on patients living for decades with the diagnosis of “cancer”— even if it’s deemed non-life threatening.
Can you tell us about the research you’re doing and how you’re working on this problem of screening and diagnosis?
Last year, we published a new study that discovered that men who are born with a particular gene mutation are more likely to have the aggressive form of prostate cancer and have worse outcomes than men born without the mutation. This gene is in the same family as the gene involved in the body’s production of the PSA protein. We’re also working on a large-scale study in Ontario looking at the combination of this gene mutation with the mutation in the BRCA gene. In women, as it is well-known in the public, because of stories like that of celebrity Angelina Jolie, a mutation in the BRCA gene is linked with breast cancer. Interestingly enough, in men, this same gene is also associated with prostate cancer! Through this type of genetic research, we are investigating whether a genetic test to identify mutational genes, will be able to help diagnose the aggressive form of prostate cancer.
How do you see prostate cancer screening, and diagnosis changing and improving in the future? What will this mean for men?
It is likely that genetic testing together with new markers and improved imaging (like MRI of the prostate) will be able to identify men at risk of developing the fatal form of the disease much earlier. Recently I saw a man in his early 40s, father of two young children that had a very aggressive form of prostate cancer. It had migrated to the bones and become a life-threatening disease. Who wouldn’t want to have diagnosed this man much earlier if we had a reliable genetic test? Physicians cannot change the development of an aggressive prostate cancer but we can try to detect it at an early, curable stage.
What do the current guidelines say about who should be tested for prostate cancer and how often?
There is currently some discussion on whether testing should be applied to the entire population of men or if this should be an individual discussion between the physician and patient. Most guidelines are recommending shared decision-making involving the patient and physician discussing the pros and cons of screening/early detection. It’s important for men to talk with their doctors about their family history and risk factors or if they have any symptoms that they’re concerned about.
