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

Pathophysiology
Sex-steroid suppression → ↑ osteoclast activity → rapid bone loss (~3–5 %/year under ADT or AI).

Key numbers

  • DEXA T-score ≤ −2.0 = osteoporosis.

  • Vertebral fracture risk ↑ 2–3 × after 2 years continuous ADT.

Prophylaxis

Agent Dose Route / Interval Notes
Zoledronic acid (Zometa®) 4 mg IV q 6–12 mo Renal adjust; dental clearance first
Denosumab (Prolia®) 60 mg SC q 6 mo No renal adjust; risk hypocalcemia
Calcium + Vit D 1200 mg + 800–1000 IU daily Oral Mandatory with both

Exercise prescription

  • Weight-bearing + resistance ≥ 3 ×/week.

  • Fall-prevention: proprioception training + balance.

Dental rules

  • Baseline dental exam.

  • No implants or extractions during bisphosphonate/denosumab use; defer ≥ 3 mo pre/post-procedure.

  • Immediate referral if exposed bone or jaw pain → suspect osteonecrosis of the jaw (ONJ).