New treatments could turn advanced prostate cancer into a 'chronic disease' instead of a death sentence
Many people with advanced prostate cancer are living much longer due to new treatments, leading prostate cancer doctors say. Though they're not often a cure, these innovations are turning a disease once considered a death sentence into a chronic illness that can be managed for years in some patients.
Dr. Laurence Klotz, a urologic oncologist at Sunnybrook Health Sciences Centre and chair of prostate cancer research at the Toronto hospital, said patients with metastatic prostate cancer — meaning it's spread to other parts of the body — live "roughly twice as long now as they did 10 or 15 years ago, which is really a significant achievement."
"The disease can be controlled, often for a long time — but a cure is generally not in the cards," Klotz told Dr. Brian Goldman, host of CBC podcast The Dose.
When former U.S. president Joe Biden announced recently that he'd been diagnosed with an aggressive form of prostate cancer that had spread to the bone, it raised questions about what the prognosis might be like for him and for others whose prostate cancers aren't detected at earlier stages.
Biden's case may be "at the worst end" of a spectrum of prostate cancers, said Klotz. That's not only because the disease has spread but because of how quickly his cancer cells are likely to duplicate based on how they look under a microscope. But that scenario is quite rare, Klotz says.
"So whereas, say, 15 years ago, the average patient with metastatic prostate cancer would live about three years, now the survival is more like five to six years," he said.
There are also "big ranges around that estimate," said Klotz, who is also a professor in the Department of Surgery at the University of Toronto.
"You have some patients who may live 10 or 15 years despite having metastatic disease. And unfortunately, you have others where the disease progresses very rapidly, despite all these new therapeutic advances, and the patient can sometimes die within a year."
Thomas Flannery is among those whose advanced prostate cancer has been managed for many years. The Toronto resident was first diagnosed with prostate cancer in 2011 at 56, when his family doctor decided to run a prostate-specific antigen blood test as part of a routine physical.
That led to a biopsy, which found cancer in both halves of the prostate gland and in the seminal vesicles, glands that produce the fluid that becomes semen.
"I ended up having a radical prostatectomy with Dr. Klotz at Sunnybrook, and following that I went on three years of what's called androgen deprivation therapy," said Flannery. At that time, the disease had already spread to Flannery's lymph nodes.
New treatmentsAndrogen deprivation therapy suppresses the body's testosterone production, a hormone most prostate cancer needs to survive. It's part of a host of treatments Flannery has needed over the years, including a course of chemotherapy in 2020.
New treatment options can be key to extending people's lives.
The standard androgen deprivation therapy works by telling the testicles to stop producing testosterone, said medical oncologist and prostate cancer researcher Dr. Kim Chi.
"Over the past five to 10 years, we know that just doing that alone, although it's very effective initially, the cancer can come back quite quickly," said Chi, who is also vice-president and chief medical officer at BC Cancer.
That's because the cancer draws testosterone from other places in the body, such as the adrenal gland, and additionally, prostate cancer can produce its own testosterone, he says.
However, a new class of drugs, called androgen receptor pathway inhibitors, block the body's ability to absorb those sources of testosterone, Chi said.
"Not only are we blocking the gasoline, which is the testosterone, we're also blocking the receptor — or blocking the engine from actually receiving that gasoline," he said. "It's like putting a blockage in the fuel line."
Extending your lifeHaving these new drugs available has dramatically improved survival rates, said Chi, who is also a professor in the Department of Medicine at the University of British Columbia.
For the portion of prostate cancers that are shown to be associated with gene mutations, promising new drugs that target the genes seem poised to prolong life even further, he said, as do drugs that deliver strong, targeted radiation directly to the prostate cancer at a molecular level.
"I'd like to see this turned into a chronic disease that we just manage and keep under control. No, we may not cure it, but we can keep it controlled for many years," said Chi.
"If I can manage somebody for five, 10, 15, 20 years until something else inevitably takes your life, then we've done a good job, too, and I think we can get there."
Lifestyle factorsNow 70, Flannery says he advises others with advanced prostate cancer to stick closely to their drug regimens but also to pay close attention to lifestyle factors.
He said he adheres to a Mediterranean diet because of its health benefits and has significantly reduced how much red meat he eats.
"The other thing that's extremely important and really difficult to explain to people is the need to do exercise."
A healthy diet and regular exercise help counter some of the negative effects of androgen deprivation therapy, he said, which can include metabolic syndrome — something that can cause weight gain around the midsection.
"It's important to keep your weight to a trim amount," he said. "You don't have to be a gym rat, but you need to get yourself into shape so that you don't get secondary comorbidities like diabetes."
At 70, Flannery is now retired from his job in the aerospace industry and works as a patient advocate, consulting with researchers on new treatment protocols. He's started a national support group for people with advanced prostate cancer and provides peer counselling.
"Right now, I'm being the general contractor for the build of a new house," said Flannery. "I like to ride a bicycle. I like to ski both cross-country and downhill."
He and his wife also enjoy sailing.
All this, despite the fact that Flannery's disease has now metastasized extensively, including to the pleura, the sac that surrounds the lungs.
"So currently I'm relatively healthy. Outward, no one would know that I have prostate cancer," he said. "I just have to take drugs every day."
cbc.ca
