Hormonal Therapy Before or With Radiation. Hormonal drugs combined with radiation therapy may improve survival rates in moderate- or high-risk groups. Patients may need to take these drugs long-term to improve outcomes. Hormonal drugs before radiation (neoadjuvant therapy) may be helpful in shrinking enlarged glands so that brachytherapy (radiation implants) can be used. An important study published in 2004 in the Journal of the American Medical Association found that for men with localized prostate cancer, a 6-month course of hormone therapy combined with radiation treatments produced greater survival rates than radiation treatment alone. Standard medical practice has generally indicated that hormone therapy should be administered for 3 years; the JAMA study suggests that a shorter regimen may be equally beneficial for some patients and may help reduce the side effects that typically accompany androgen-suppressing drugs.
LH-RH Agonists
The primary drugs used for suppressing androgens are called luteinizing hormone-releasing hormones (LH-RH) agonists. They include:
- Leuprolide (Lupron, Leuprogel). Studies report that disease progression is prevented in 72% of men taking daily leuprolide and up to 89% of those taking monthly injections. Certain men, however, may not respond to injections. Drug delivery using implants is under investigation.
- Goserelin (Zoladex). Partial responses of 60 - 80% have been reported. A controlled release formulation has been developed that increases the time between injections from 4 weeks to 3 months.
- Buserelin.
LH-RH drugs block the pituitary gland from producing hormones that stimulate testosterone production. Patients must have injections of LH-RH agonists for the rest of their lives.
Testosterone and PSA Surges. Treatment with LH-RH agonists produces a testosterone surge in the first week, which may actually intensify symptoms. After this phase, testosterone levels drop to near zero. Leuprogel, a newer leuprolide, may pose a lower risk for this effect. Researchers are investigating other drugs, such as GnRH antagonists, that do not produce this surge.
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