PORTLAND, Ore. -- A small adhesive estrogen patch worn by men being treated for advanced prostate cancer lowers cholesterol, according to a new study conducted by Oregon Health & Science University Cancer Institute researchers.
This is important because men who have advanced prostate cancer are often treated with hormone deprivation therapy, which turns off testosterone to slow the growth of prostate cancer. Testosterone suppression is effective in controlling prostate cancer, but is associated with high cholesterol that may put men at greater risk for premature heart disease.
"Our data, while preliminary, suggest that estrogen skin patches counteract adverse effects of hormone therapy that raise cholesterol in men with prostate cancer," said Tomasz M. Beer, M.D., director of the Prostate Cancer Program in the OHSU Cancer Institute and principal investigator of the study.
"We found that transdermal estrogen decreased overall cholesterol levels by 10 percent. The effect was even greater on LDL cholesterol while HDL, the 'good cholesterol,' was increased. Importantly, the patch estrogen did not cause triglyceride levels to rise, something that is common with oral estrogen preparations," Beer said.
Estrogen is known to induce testosterone suppression. Given orally, however, estrogen is associated with a high risk for blood clots that may involve both veins and arteries, and may include heart attacks. The OHSU group hypothesized that transdermal estrogen would be less likely to cause blood clots and preliminary analysis of their data support this premise.
"Given more study, estrogen skin patches may prove to be an alternative to common methods of hormone deprivation for prostate cancer as it provides testosterone suppression while improving cholesterol levels," Beer said.
In their study, Jonathan Q. Purnell, M.D., assistant professor of medicine (endocrinology, diabetes and clinical nutrition) in the OHSU School of Medicine, together with Beer and colleagues examined the effects of transdermal estrogen cholesterol and other lipids that have been associated with heart disease. The study was presented on June 7, 2004, at the American Society for Clinical Oncology annual meeting in New Orleans, La.
Eighteen androgen independent prostate cancer patients aged 49 to 92 participated in the study. They were treated with six 7.6 milligram (45.6 milligrams total) patches every seven days for eight weeks. Blood cholesterol and lipid levels were measured before and eight weeks after beginning transdermal estrogen therapy. Whole body composition and body fat also were measured.
"Transdermal estrogen increased protective cholesterols, decreased those associated with heart disease, and did not produce adverse effects seen with oral formulations of estrogen," Beer said. "While our results are promising, larger controlled studies are needed to determine the impact of transdermal estrogen therapy on cardiovascular risk."
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.
This study was funded in part by the National Cancer Institute, a component of the National Institutes of Health.
Particulars: ASCO Abstract No. 8035, Transdermal estrogen therapy improves cholesterol levels and lipid profiles in men with prostate cancer
Tomasz M. Beer, M.D., assistant professor of medicine (hematology and medical oncology) in the OHSU School of Medicine and director of the Prostate Cancer Program in the OHSU Cancer Institute.
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