SOURCES: Nicholas James, M.D., Ph.D., director, Cancer Research Unit, University of Warwick, Coventry, England; Peter Yu, M.D., director of cancer research, Palo Alto Medical Foundation, and president, American Society of Clinical Oncology
THURSDAY, May 14, 2015 (HealthDay News) -- Starting the chemotherapy drug docetaxel at the same time as hormone therapy can improve survival for men with newly diagnosed, advanced prostate cancer, British researchers say.
Currently, chemotherapy is generally given after hormone therapy stops working. But the new study found that when the two therapies were paired at the start of treatment, patients lived an average of 10 months longer.
The combination had even greater benefits for men whose prostate cancer had spread to other parts of their bodies -- known as "metastatic" cancer. These men experienced an average 22-month improvement in their overall survival, the findings showed.
"We hope our findings will encourage doctors to offer docetaxel to men newly diagnosed with metastatic prostate cancer, if they are healthy enough for chemotherapy," said lead author Dr. Nicholas James, director of the Cancer Research Unit at the University of Warwick in Coventry, England.
Since the 1940s, hormone therapy has been the standard treatment for men with advanced prostate cancer. "Essentially we treat men by shutting off the production of male hormones, either surgically or with drugs," James said.
Cancer doctors have followed this tactic because hormone therapy is less toxic and has fewer side effects than chemotherapy, said the president of the American Society of Clinical Oncology, Dr. Peter Yu.
"The bias has been to use hormone therapy until there's no response left, and then at the last moment use chemotherapy," said Yu, who's also the director of cancer research at Palo Alto Medical Foundation in California. He described this as a "self-defeating strategy, because you're using chemotherapy when the disease has evolved to a point where it's much more aggressive."
Findings from the study are scheduled to be presented May 31 at the annual meeting of the American Society of Clinical Oncology in Chicago. Research presented at meetings is generally viewed as preliminary until published in a peer-reviewed journal.
This British-led clinical trial sought to test whether adding chemotherapy up front would help prolong the lives of men with prostate cancer. The study was dubbed STAMPEDE, for Systemic Therapy in Advancing or Metastatic Prostate Cancer: Evaluation of Drug Efficacy.
Since 2005, researchers have recruited nearly 3,000 prostate cancer patients who'd never had hormone therapy before. About three out of five men in the study had prostate cancer that had spread to other parts of their bodies, while the rest had high-risk, advanced prostate cancer that had not yet spread.
The men entered one of four treatment regimens. They all were given three years of hormone therapy. One group only received the hormone therapy. Another group was given the chemotherapy drug docetaxel in addition to the hormone therapy. The third group got zoledronic acid, a drug used to treat prostate cancer that has spread to bones, along with hormone therapy. The last group got the works -- hormone therapy, docetaxel and zoledronic acid.
In addition, men who were candidates for radiation therapy in any of the groups also received that treatment, according to the study.
After an average follow-up of 42 months, 948 men in the trial had died, the researchers reported.
Men treated with hormone therapy alone lived an average of 67 months. Those treated with docetaxel and hormone therapy ended up surviving an average of 77 months, a relative improvement of 24 percent.
Those with invasive prostate cancer survived an average 65 months when they received docetaxel and hormone therapy together, compared with 43 months for men who received just hormone therapy, the investigators found.
The chemotherapy drug appeared to benefit men by holding their cancer at bay. Docetaxel extended the time to relapse by 38 percent in all patients, the researchers said.
Zoledronic acid didn't have any impact on survival, even when it was combined with both docetaxel and hormone therapy, according to the study.
While the combination of chemotherapy and hormone therapy worked, Yu said doctors will have to take into account the potential for side effects to drastically diminish a patient's quality of life.
Hormone therapy can cause fatigue, anemia, brittle bones, decreased muscle mass and loss of sexual function, while chemotherapy drugs open the body to a host of debilitating side effects, according to Yu and James.
But the researchers noted that the addition of chemotherapy to hormone therapy in this study was well-tolerated. Very few men dropped out due to side effects from the chemotherapy, they added.
"There's no question each of these treatments we introduced has its own possibility for side effects, and so if we're combining therapies there's the potential that you could have a greater negative impact on quality of life," Yu said.
But, he added, "I think we also recognize from other trials that treating the cancer more effectively has a positive benefit in terms of quality of life as well."
Future research will focus on whether this combination therapy also can help men with less aggressive prostate cancer, James said.
For more about prostate cancer, visit the American Cancer Society.