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PORTLAND, Ore. -- The gold standard of care for men whose cancer has spread beyond the prostate is hormone deprivation therapy. However, little is known about the effectiveness of this therapy in men whose cancer remains localized within the prostate.
"Even though no data on the effectiveness of hormone deprivation therapy for men with localized prostate cancer exists, recent studies of physician practice trends show that it is being used for this purpose with increased frequency," said Mark Garzotto, M.D., director of urologic oncology at the Portland Veterans Affairs Medical Center, assistant professor of surgery (urology) in the Oregon Health & Science University School of Medicine, and member of the OHSU Cancer Institute.
Hormone deprivation therapy shuts down testosterone, which is often responsible for making prostate cancer grow. Currently accepted treatments for localized prostate cancer include surgery and radiation.
In one of the first studies examining the effectiveness of hormone deprivation as a primary therapy for localized prostate cancer, Garzotto and colleagues found that younger men and those with higher grade tumors are more likely to experience disease progression during treatment. They also found that men with localized prostate cancer on hormone therapy experience a higher than expected rate of bone fractures caused primarily by treatment-related osteoporosis.
"Our study gives physicians valuable data for use in counseling men with localized disease who are considering hormone deprivation as their primary treatment," said Garzotto. "Based on our results, we feel that the use of hormone therapy for localized prostate cancer warrants further investigation before it can be considered an acceptable alternative to the standard treatment options."
Garzotto presented study results at the American Society for Clinical Oncology annual meeting in New Orleans, La., on June 6, 2004.
Garzotto and colleagues reviewed records of men who had chosen hormonal deprivation therapy as their sole initial treatment for localized prostate cancer at the PVAMC between 1993 and 2000. Age, race, overall health, family history, prostate-specific antigen (PSA), PSA density, prostate exam findings, tumor grade or the extent cancer cells had differentiated from normal cells (as measured by Gleason score), and percent of positive prostate biopsies at diagnosis were evaluated.
Eighty-one men with a median age of 73 were followed for a median of 54 months. Researchers extracted data on PSA response, the advent of bone fractures, the loss of cancer control, development of metastatic disease, progression of localized disease that caused symptoms or signs, and overall survival.
"Hormone deprivation resulted in reasonable control of localized prostate cancer, however, younger patients in this study tended to fare worse," Garzotto said.
Researchers found that after five years, about 26 percent of patients experienced treatment failure. This was determined by two consecutive tests showing rising PSA levels. Men with a Gleason score higher than 6 and those younger than 70 had a higher risk of losing cancer control during treatment. Overall patient survival was 59 percent during the study period.
About one in four men receiving hormonal deprivation therapy for localized prostate cancer suffered bone fractures. Ninety percent of these were caused by osteoporosis with the remainder being caused by metastatic disease.
"Bone fractures may be more common in men with localized cancer because of the prolonged treatment period of hormone deprivation," Garzotto said. "Trials comparing hormone deprivation to established therapies are needed to determine whether the treatment results are comparable."
Prostate cancer is the most common cancer in men and the second leading cause of cancer-related death in American men. Overall, one in six men will develop prostate cancer during his lifetime.
ASCO Abstract No. 4627, Outcomes of androgen deprivation as sole therapy for localized prostate cancer
NOTE: A photo of Garzotto is available at http://www.ohsu.edu/news/2004/060704garzotto.html
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