Prostate cancer is the most commonly diagnosed cancer in men. Around 12.5 percent of Canadian men can expect to be diagnosed with prostate cancer in their lifetime. Fortunately, there is a wealth of treatments and therapies for prostate cancer, but the flip side of that same coin is that it can be difficult for physicians and patients to decide what the best course of action is in any given case. Recently, genomic testing of prostate cancer cells has been providing a valuable new tool to help guide treatment.

Genomic and genetic testing is a fast-growing area of research across all medical fields, but genomic testing for prostate cancer differs somewhat from some of the more commonly known tests. Unlike, say, the gene test for breast cancer, through which women without cancer can learn if their genes put them at greater risk, this test provides information about the genetics of the disease itself in men who already have prostate cancer. “This test is about profiling biopsy tissue to determine the biological behaviour of the cancer,” explains Dr. Neil Fleshner, Head of the Division of Urology at the University Health Network. “Is it going to be fast-growing or slow-growing, and how would that potentially change treatment options?” It’s a prognostic test that can provide meaningful predictions on the course a specific person’s cancer is likely to take.

Finding the right treatment for the right patient

Because prostate cancer has what is known as a “heterogeneous prognosis,” meaning that some cases are much more worrying than others, it is especially important that physicians be able to analyze the specific behaviour of the cancer in each individual patient before working with that patient to develop a treatment plan. “Historically, we’ve had three clinical parameters that we’ve used in our discussion with the patient to make a decision about what to do: the PSA, the biopsy histopathology findings and the digital rectal exam,” explains Dr. Neal D. Shore, Medical Director of the Carolina Urologic Research Center. “Genomic testing has independent information on top of those three traditional parameters. It’s additive. It’s a fourth parameter that helps with decision making.”

“It’s a prognostic test that can provide meaningful predictions on the course a specific person’s cancer is likely to take.”

And having more information is a huge benefit, when research has consistently shown that prostate cancers have historically been over-treated. The therapies available for prostate cancer are robust, but they have costs and side effects associated with them. “Everyone agrees that high-risk patients need treatment, and everyone pretty much agrees that low-risk patients don’t need treatment,” says Dr. Fleshner. Genomic testing is providing a new way to more confidently determine which cases fall in which risk category.

Over the past few decades, the survival rates for prostate cancer have skyrocketed, as has the quality of life for those living with the disease. Much of that comes down to the development of new treatments and therapies, but just as important is knowing when, and indeed whether, to use them. For both doctors and patients, access to good information not just about prostate cancer in general, but also about each person’s individual cancer specifically, is the foundation on which good treatment decisions are built.