Biological synergy
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Hormone therapy shrinks gland/tumor volume, reducing hypoxia and improving dose conformity.
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Cell-cycle arrest in G1 enhances radiosensitivity.
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Micro-environmental effect: decreased VEGF → better perfusion → higher O₂ → ↑ radiation kill.
Clinical evidence
| Trial | Population | Key finding |
|---|---|---|
| RTOG 8610 / EORTC 22961 | Locally advanced prostate | ADT + RT ↑ OS ~20 % vs RT alone |
| TROG 96.01 | Locally advanced prostate | 3–6 mo neoadj ADT ↓ biochemical failure |
| EBCTCG Meta-analysis | ER+ breast | Endocrine therapy + RT ↓ local recurrence ~ 50 % |
Practical integration
| Cancer | Sequence | Duration |
|---|---|---|
| Prostate | Start ADT 2–3 mo before RT → continue during + 18–36 mo after | Long-term for high-risk |
| Breast | RT usually after chemo; endocrine can start concurrently or ≤ 3 weeks post-RT | 5–10 y total endocrine |
(NCCN Prostate 2025; ESMO Breast 2024)