For years now, we’ve all been inundated by “pink ribbon” campaigns dedicated to raising awareness and funding for breast cancer research. Even though nearly the same number of people will be diagnosed with prostate cancer this year as breast cancer, and prostate cancer will kill nearly as many people in the US this year as invasive breast cancer, it has hardly gotten the same attention.
As a result, there has been little change in treatment options for those with prostate cancer over the past few decades. Given that prostate cancer is generally slow-growing, current treatment methods have actually been quite effective unless someone was diagnosed with advanced prostate cancer. For these men, surgery and radiation are no longer curative options because at that point, the disease has spread throughout the body.
The good news: In just the past three years, pharmaceutical companies have developed a number of drugs—both oral and intravenous medications—that have the potential to extend the lifespans of men with advanced prostate cancer.
Some of these drugs are on the market now, and some may get FDA approval this year, and they all point to a promising trend—increased research into treatments for men who would otherwise be out of options.
To get his perspective on this news, I called Bruce Roth, MD, a professor of medicine in the division of oncology at Washington University School of Medicine in St. Louis, medical oncologist at the university’s Siteman Cancer Center and a noted researcher and lecturer in the area of novel treatments for advanced prostate cancer.
“We’ve known for 70 years that testosterone stimulates some prostate cancer cells to grow,” Dr. Roth said. “And we’ve known that by withdrawing testosterone, either by surgical removal of the testicles or by giving injections that trick the body into not making testosterone, about 70% of patients respond, meaning that a portion of their prostate cancer cells are killed off.”
I know what you’re thinking. That seems like a drastic step, since testosterone is an important hormone—indeed, many would say a defining hormone—for men. Side effects of this treatment can include loss of sex drive, gradual bone-density loss, and mood changes such as depression. But, as Dr. Roth explained, when it comes to advanced prostate cancer, it’s all about increasing survival, and experts have felt that in many instances, based on the patient’s overall health and other factors, the benefit outweighs the risks—at least for a while. The problem with this method, Dr. Roth said, has been that, eventually, cancer would become resistant to the hormone-suppressing therapy and would continue growing.
Or at least, that’s been what they thought was happening…
Around 10 years ago, researchers discovered that seemingly hormone-deprived cancer was actually responding to tiny levels of testosterone that were still being produced in the body, either by adrenal glands or, sometimes, by the tumor itself. At that time, the experts hypothesized that if they could block these additional sources of hormones, they’d get better results.
And that’s how some of today’s promising medications work—and results of studies with these drugs are promising. For example, a study of one of the hormone-blocking drugs currently on track to receive FDA approval this year extended median survival by three to five months. Dr. Roth noted that three to five months is only the median time-frame, so many patients are surviving for much longer than that. Common but mild side effects may include discomfort and fatigue, while less common but more severe side effects may include liver toxicity, diarrhea and bone fractures. Dr. Roth said that it appears that men can survive without testosterone for decades, though the side effects can add up and may negatively impact quality of life. Yet all in all, in my opinion, this is promising news.
These new prostate cancer drugs are expensive—far beyond what the average person would be able to afford. “For instance, abiraterone (Zytiga) costs about $5,000 to $6,000 a month,” said Dr. Roth. But anything new is expensive. And as more of these drugs come to market, the hope is that the costs will come down. These drugs are sometimes covered by insurance, but not always (and not always fully).
Clinical trials are still going on for some of these drugs. If you’re interested in joining one, talk to your doctor, and look into the upcoming trials at http://ClinicalTrials.gov/.
Source: Bruce Roth, MD, professor of medicine, division of oncology, Washington University School of Medicine, and medical oncologist, Siteman Cancer Center, both in St. Louis.