New approaches to the
therapy for some endocrine-dependent
tumors with analogs of
hypothalamic hormones are being developed on the basis of experimental studies in animal models. Analogs of
luteinizing hormone-releasing
hormones (
LH-RH) may open new vistas for the treatment of some
hormone-dependent
carcinomas. It has been clearly demonstrated that both agonistic and antagonistic analogs of
LH-RH can inhibit the growth of rat prostate
tumors. A successful treatment of
androgen-dependent
prostate cancer with agonistic analogs of D-Trp6-LH-RH, D-Ser(But)6des-Gly-NH2(10)-LH-RH ethylamide, and D-Leu6-des-Gly-NH2(10)-LH-RH ethylamide has been documented in several hundred patients. The data accumulated so far from clinical trials suggest that
LH-RH agonists can be used as an effective endocrine
therapy for prostate
carcinoma,
therapy avoiding the side effects of
estrogen and the psychologic impact of
castration. Experimental animal studies and some clinical trials suggest that
LH-RH agonists and/or antagonists might also be useful in the treatment of
breast cancer. The results of experiments with various hypothalamic analogs in animal models of
chondrosarcomas,
osteosarcomas, and other
tumors appear to be encouraging, but the potential clinical efficacy of
LH-RH analogs in the treatment of human
hormone-sensitive
cancers other than breast and prostate remains to be investigated. The approach to treatment of
hormone-dependent
tumors based on analogs of
hypothalamic hormones might become a useful addition to conventional methods for
cancer therapy.