Concerns regarding the association of hormone therapy used to treat prostate cancer with cardiovascular disease in some older men may lead doctors to forgo hormone treatment solely on the basis of age. But a new study by physicians at Fox Chase Cancer Center shows that men over age 70 with high-risk prostate cancer lived longer and experienced increases in PSA less frequently when treated with long-term androgen deprivation therapy.
The benefit of long-term (i.e. 2-3 years) androgen deprivation therapy has been established in high-risk prostate cancer patients in several prospective, randomized clinical trials. However, concern that androgen deprivation therapy may result in cardiovascular disease, particularly in older patients men with certain risk factors for cardiovascular disease, has led investigators to question its role in older men.
"Several studies have demonstrated a survival benefit when androgen deprivation therapy is used along with radiotherapy in men with high-risk, clinically localized prostate cancer," said the study's lead author, Joshua Silverman, MD, PhD, a resident in the Department of Radiation Oncology at Fox Chase. "What we did not know until now is whether this benefit outweighs the risks of cardiovascular and metabolic adverse effects from androgen deprivation therapy."
In this retrospective study presented September 24 at the 50th annual meeting of the American Society for Therapeutic Radiology and Oncology, researchers identified men with prostate cancer that was confined to the prostate, but considered high-risk (i.e. pre-treatment PSA ≥ 20, Gleason score 8-10, or larger tumors palpable during digital rectal exam) and looked at outcomes with and without the use of hormone therapy.
"We know the risk of distant metastasis, recurrence and death are higher when androgen deprivation therapy is not part of radiation treatment," said Silverman. "We wanted to see if age should be a determining factor for treatment with hormone suppression."
Researchers found the overall rate of biochemical failure (i.e., a rise in the PSA level) is lower for men who received hormone therapy regardless of age. A rise in PSA can indicate the recurrence or spread of prostate cancer and often leads to more testing and more aggressive treatments.
"We saw the greatest advantage of hormone therapy among men who received a longer duration of androgen deprivation therapy, including those with pre-existing cardiovascular and metabolic concerns," said Silverman.
A longer duration (more than 12 months) of hormone therapy resulted in a greater overall survival for all men (≤12 months-87 percent, ≥ 12 months-98 percent; p=0.02) including in men older than 70 (≤12 months-80 percent, ≥ 12 months-98 percent; p=0.03).
Men under 70 who received hormone therapy had a greater 5 year overall survival rate (96 percent v 91 percent; p0.03) than did men over 70 (89 percent v. 86 percent; 0.17).
"This may be explained in part by a trend toward greater pre-existing cardiovascular concerns in men over age 70," Silverman said.
Still, Silverman said, "We concluded that age alone should not be considered a contraindication to hormone treatment in high-risk patients. While co-morbidities may influence clinical decision-making regarding androgen deprivation therapy, we do not have enough data to select patients who should or should not receive treatment of a shorter duration based on age alone."
"One weakness of this study is selection bias because men in this retrospective analysis were not randomized to androgen deprivation therapy." Silverman said, "We still need to continue our careful consideration of each individual's health before recommending androgen deprivation therapy."
Silverman added that the study does not address the impact hormones may have on a man's quality of life. The adverse effects of hormones include muscle loss, cognitive issues, loss of libido, and osteoporosis.
The study was funded by Fox Chase. Other authors include Karen Ruth, Eric M. Horwitz, Alan Pollack, David Y. T. Chen, and Mark K. Buyyounouski of Fox Chase.
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