## ADT for Intermediate-Risk Localized Prostate Cancer ### Treatment Context This patient has intermediate-risk localized prostate cancer (T2b, PSA 8, Gleason 7) and is receiving EBRT. ADT is indicated as neoadjuvant and concurrent therapy with radiation in intermediate-risk disease based on randomized trials (RTOG 94-06, RTOG 99-10). **Key Point:** GnRH agonists (goserelin, leuprolide) are the standard first-line agents for ADT in localized and locally advanced prostate cancer. They achieve complete androgen blockade by suppressing testicular testosterone production. ### Why GnRH Agonists Are Preferred | Feature | GnRH Agonist | Anti-androgen | Novel Hormone Agent | |---------|-------------|---------------|---------------------| | **Mechanism** | Suppresses testicular T | Blocks androgen receptor | Blocks adrenal + testicular T | | **Efficacy** | Complete suppression | Partial (monotherapy) | Superior but for mCRPC | | **Cost** | Lower | Moderate | Very high | | **Role in localized disease** | Standard first-line | Not monotherapy | Not indicated | | **Toxicity** | Hot flushes, gynecomastia, sexual dysfunction | Hepatotoxicity risk, gynecomastia | Greater side-effect burden | ### Standard GnRH Agonists in India - **Goserelin acetate** (Zoladex): 3.6 mg SC depot every 28 days OR 10.8 mg every 12 weeks - **Leuprolide acetate**: 7.5 mg IM monthly OR 22.5 mg IM every 3 months - **Triptorelin**: 3.75 mg IM monthly OR 11.25 mg IM every 3 months **High-Yield:** In localized and locally advanced prostate cancer treated with EBRT, GnRH agonists (± anti-androgen) are the standard of care. Duration of ADT depends on risk: intermediate-risk typically receives 6 months of ADT (neoadjuvant + concurrent with EBRT). ### Mnemonic for ADT Agents by Setting **"GLAND for Localized, Novel for Metastatic"** - **G**nRH agonists → Localized/locally advanced (standard) - **L**ocal therapy (surgery/RT) → Always consider - **A**nti-androgens (bicalutamide) → Adjunct or flare prevention - **N**ovel agents (abiraterone, enzalutamide) → mCRPC only - **D**ocetaxel → mCRPC second-line ### Clinical Pearl When starting a GnRH agonist, co-administer an anti-androgen (bicalutamide 50 mg daily for 7 days) to prevent the "flare" phenomenon—transient surge in testosterone causing pain and urinary obstruction in the first 1–2 weeks. ### Why Other Options Are Incorrect for This Setting - **Bicalutamide monotherapy:** Incomplete androgen blockade; inferior to GnRH agonists in localized disease and not recommended as monotherapy. - **Abiraterone:** Indicated only for mCRPC, not localized disease; unnecessary cost and toxicity burden. - **Enzalutamide:** Indicated for mCRPC or high-risk metastatic disease; no evidence in localized prostate cancer.
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