Most Canadians likely know a man who has been diagnosed with prostate cancer. It’s a startling and stark reality. The disease, which affects a small, walnut-like gland located between a man’s bladder and reproductive organ, is the single most common cancer among Canadian men.

“One in eight Canadian men are diagnosed with prostate cancer in their lifetime,” says Dr. Tony Finelli, Chief of Urology and Genitourinary Site Lead at Princess Margaret Cancer Centre. “You look across Canada, and in any given year, probably 20,000 men will be diagnosed with prostate cancer. If you took all males diagnosed with cancer in a year, prostate cancer makes up one-fifth of them.”

The current treatment landscape

Thanks to public campaigns like Movember, many people have at least some understanding of prostate cancer. Few, however, are aware of just how serious the disease can be. “I think awareness is improving,” notes Dr. Finelli, “but we have a lot of mixed messaging and confusion because of the duality of the disease. It’s not always a disease that you’re going to die from, but in a subset of men, it is. Although 20,000 men will be diagnosed each year, approximately 4,000 will die from the disease annually.”

Dr. Finelli explains that prostate cancer is an androgen- or testosterone-driven cancer. “That doesn’t mean that testosterone causes the cancer, but it facilitates the growth of the cancer. So, once you develop prostate cancer it feeds off testosterone,” he says. “The standard of care for men with advanced prostate cancer, or metastatic prostate cancer, is to castrate them medically. That’s usually in the form of an injection that shuts down a man’s ability to make testosterone and that will cause the tumours to shrink.”

Sadly, sometimes hormone therapy does not work and the cancer continues to spread and becomes fatal. “Metastatic castration-resistant prostate cancer (mCRPC) is when the cancer is progressing in the setting of no testosterone,” says Dr.Finelli. “That means the prostate cancer has now become independent of androgen deprivation and it’s spreading to other parts of the body. mCRPC is basically advanced prostate cancer, which is synonymous with metastatic prostate cancer.”

Typically, at this stage, treatment for patients with mCRPC is focused mainly on palliative care and patients often experience pain and major decreases in their quality of life.

A new treatment horizon

Thankfully, in recent years an innovative category of drugs has offered hope and a longer lifespan for patients with mCRPC. “When a patient develops castration resistance, doctors need to add therapies. One type of therapy you could add is chemotherapy in the form of a drug. But now there’s a whole new class of drugs that fall under a new category we’ve been calling ARAT,” says Dr. Finelli. “These drugs are androgen receptor axis targeted, meaning that they inhibit androgen receptors — they impede the connection between androgens and androgen receptors.”

These new pharmaceuticals are significant game-changers because cancer cell growth slows down if androgens can’t communicate with their receptors. “You look at the studies that are now almost five years old, and you see that the drugs not only prolonged survival, they also improved quality of life,” says Dr. Finelli.

“We’ve made tremendous progress in how we care for men in this advanced state, and we’ve improved their quantity and quality of life,” he says. “It’s exciting to consider that future studies might show that when we add these new drugs earlier to treatment there may be even greater benefits.”

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