Adding Hormone Therapy to Radiation Therapy Helps Men Live Longer With Locally Advanced Prostate Cancer, Fox Chase Cancer Center Analysis Shows
PHILADELPHIA (November 3, 1999) -- National clinical trials sponsored by the Radiation Therapy Oncology Group (RTOG) have previously demonstrated that men whose prostate cancer extends beyond the prostate gland live longer when they receive follow-up, or adjuvant, hormone therapy as well as radiation therapy. Hormone therapy generally uses drugs to block production of male sex hormones (testosterone and other androgens), which often promote prostate cancer growth.
To further define subsets of patients who would benefit from the addition of hormone therapy, researchers at Fox Chase Cancer Center, RTOG and other institutions re-analyzed data from these RTOG trials, conducted from 1987 to 1992. The new analysis focused on treatment outcomes for 993 trial participants who had had surgery for prostate cancer or who had no surgery but had locally advanced prostate cancer that had not yet spread, or metastasized, to lymph nodes.
"Our analysis showed that men receiving hormonal drugs along with radiation therapy have a definite advantage for lowering levels of prostate-specific antigen and decreasing the rates of distant metastases," said Fox Chase radiation oncologist Eric M. Horwitz, M.D., who specializes in the treatment of prostate cancer. "The advantage was greatest among the men who received long-term hormone therapy compared to short-term hormone therapy." Horwitz will present the results today at the American Society for Therapeutic Radiology and Oncology (ASTRO) conference in San Antonio, Texas.
All patients studied had been diagnosed with locally advanced prostate cancer. All received external-beam radiation therapy, targeting high-energy radioactive waves to the tumor. For some men, radiation was the primary therapy. Others had radiation treatments after surgery to remove the prostate.
Almost half of the 993 patients included in the Fox Chase re-analysis had been randomly assigned to receive hormone therapy as well as radiation. Of these, 280 received long-term treatment with the drug goserelin, which blocks hormone production. This hormone therapy began during the last week of radiation therapy and continued indefinitely. Another 210 patients received the hormone-modifying drugs goserelin and flutamide on a short-term basis, two months before and during radiation therapy.
Measures of survival used in the re-analysis included the standard of no biochemical evidence of disease (bNED) after five years, defined as a prostate-specific antigen (PSA) level of less than 1.5 ng./ml. (nanograms per milliliter of blood). Measures at eight years included survival free of distant metastases after eight years. Another measure was cause-specific survival, based on whether study participants who eventually died did so because result of their cancer. The majority died of something other than prostate cancer.
"When treated with adjuvant hormones and radiation therapy, patients with locally advanced non-metastatic prostate cancer show improved rates of biochemical disease-free survival and survival without distant metastases," Horwitz summarized. "Long-term hormone therapy is superior to short-term hormones," he said.
The latter finding was shown by statistically significant improvements in disease-free survival, metastases-free survival and cause-specific survival among men with pretreatment Gleason scores between 7 and 10. The Gleason score is determined by a microscopic assessment of how aggressive the cancer cells are-the more aggressive the cancer, the higher the score.
Fox Chase Cancer Center is one of 36 National Cancer Institute-designated comprehensive cancer centers in the nation. The Center's activities include basic and clinical research, prevention, detection and treatment of cancer and community outreach programs.
Note to Editor: The study will be presented by Dr. Horwitz at the ASTRO annual conference in San Antonio, Texas, on Nov. 3, 1999. For more information about the ASTRO conference, call Keri Sperry at 703-295-6775.
Fox Chase Cancer Center, part of Temple University Health System, is one of the leading cancer research and treatment centers in the United States. Founded in 1904 in Philadelphia as one of the nation’s first cancer hospitals, Fox Chase also was among the first institutions to receive the National Cancer Institute’s prestigious comprehensive cancer center designation in 1974. Fox Chase researchers have won the highest awards in their fields, including two Nobel Prizes. Fox Chase physicians are routinely recognized in national rankings, and the Center’s nursing program has achieved Magnet status for excellence three consecutive times. Fox Chase conducts a broad array of nationally competitive basic, translational, and clinical research and oversees programs in cancer prevention, detection, survivorship, and community outreach. For more information, call 1-888-FOX-CHASE (1-888-369-2427).