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Selective estrogen receptor modulators to prevent treatment-related osteoporosis

Matthew R Smith

    Reviews in Urology
    |September 21, 2006
    PubMed

    Insights

    Gonadotropin-releasing hormone (GnRH) agonists cause bone loss in men by lowering estrogen. Selective estrogen receptor modulators may prevent this osteoporosis in prostate cancer patients.

    Area of Science:

    • Endocrinology
    • Oncology
    • Bone Metabolism

    Background:

    • Gonadotropin-releasing hormone (GnRH) agonists are used to treat prostate cancer, inducing hypogonadism.
    • This hypogonadism leads to decreased bone mineral density and increased fracture risk in men.
    • Estrogen deficiency, not testosterone deficiency, is implicated in the adverse skeletal effects of GnRH agonists.

    Purpose of the Study:

    • To investigate the role of estrogen in GnRH agonist-induced bone loss.
    • To evaluate selective estrogen receptor modulators (SERMs) for preventing osteoporosis in men undergoing GnRH agonist therapy for prostate cancer.

    Main Methods:

    • Review of existing evidence on GnRH agonists, bone density, and sex hormones in men.
    • Analysis of preliminary data on SERMs (raloxifene, toremifene) in GnRH agonist-treated men.
    • Description of an ongoing pivotal trial assessing toremifene's effects on fractures.

    Main Results:

    • GnRH agonists significantly reduce serum testosterone and estrogen levels.
    • Preliminary data indicate that raloxifene and toremifene may increase bone mineral density in men treated with GnRH agonists.

    Conclusions:

    • Estrogen plays a critical role in maintaining male bone health.
    • SERMs show promise for preventing or treating osteoporosis associated with GnRH agonist therapy in prostate cancer patients.
    • Further research, including the ongoing pivotal study on toremifene, is needed to confirm these skeletal benefits.

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