Course Content
Module 1 — Principles of Hormone Therapy in Oncology
Mechanism and Dosing Overview Aromatase Inhibitors (AIs): block the enzyme aromatase (CYP19A1), which converts androgens to estrogens in adipose and peripheral tissues. Examples: Anastrozole 1 mg orally daily, Letrozole 2.5 mg orally daily, Exemestane 25 mg orally daily. These are the preferred agents in postmenopausal women with estrogen receptor–positive breast cancer. Selective Estrogen Receptor Modulators (SERMs): such as Tamoxifen 20 mg orally daily — bind the estrogen receptor and act as antagonists in breast tissue but partial agonists in bone and endometrium. Selective Estrogen Receptor Degraders (SERDs): such as Fulvestrant 500 mg intramuscularly on days 0, 14, 28, then every 28 days thereafter — promote estrogen receptor degradation. CYP17 Inhibitors: Abiraterone acetate 1000 mg orally daily on an empty stomach plus Prednisone 5 mg orally twice daily — block the CYP17A1 enzyme, suppressing androgen synthesis in adrenal glands and tumors. Gonadotropin-Releasing Hormone (GnRH) Agonists and Antagonists: Leuprolide 7.5 mg subcutaneously every 4 weeks or depot every 3–6 months; Degarelix 240 mg subcutaneously loading dose, then 80 mg every 4 weeks; Relugolix 120 mg orally daily — suppress testosterone or estrogen production by downregulating or directly blocking pituitary gonadotropin release.
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Hormone Therapy for Cancer Patients: Mechanisms, Indications, and Clinical Practice
Endpoint Breast (Endocrine vs Chemo) Prostate (ADT combinations)
Overall Survival (OS) Similar for low-risk ER+; AI + targeted > AI alone ADT + AR antagonist ↑ OS 30–35% vs ADT alone
Disease-Free Survival (DFS) ↑ ~40–50% with endocrine therapy vs none ↑ ~20–30% with long-term ADT vs short-term
QoL impact Hot flushes, arthralgia, sexual dysfunction, osteopenia Fatigue, loss of libido, metabolic changes
Bone health loss AIs > SERMs ADT (esp. > 12 mo)
Mitigation DEXA + bisphosphonates / denosumab Same + exercise / vitamin D

Patient-reported scores

  • FACT-P: maintained better QoL with intermittent ADT.

  • EORTC QLQ-C30: most domains recover within 6 months post-therapy pause.

  • IPSS: often improves when prostate volume shrinks after ADT.