Emerging potential of parenteral estrogen as androgen deprivation therapy for prostate cancer

Abstract

Androgen deprivation therapy (ADT) is a key management strategy for prostate cancer (PC), achieved commonly by administration of luteinizing hormone-releasing hormone agonist (LHRHa), ADT markedly suppresses both male and female sex hormones which results in "castration syndrome", a constellation of adverse events such as muscle weakness, impairment of glucose and lipid metabolism, impotence, osteoporosis, and fractures. Recent evidence suggests that estrogen, in the parenteral form, may emerge as an alternative to LHRHa as it offers potential benefits of arresting PC growth as well as avoiding some of the estrogen deficiency related toxicities of LHRHa by maintaining endogenous levels of estrogen.

Keywords: Androgen deprivation therapy; parenteral estrogen; prostate cancer.

Figure 1

Inhibition of hypothalamic-pituitary-gonadal axis; estrogen inhibits testicular androgen production by negative feedback, luteinizing hormone-releasing hormone agonist down-regulates anterior pituitary receptors and suppresses release of luteinizing hormone and follicle-stimulating hormone, subsequently diminishing androgen formation in testes

Figure 2

Luteinizing hormone-releasing hormone agonist-induced hypogonadism causes adverse effects related to both testosterone and estrogen deficiencies