Letrozole (breast-cancer chemoprevention context — investigational/off-label)
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| ID | DRUG-LETROZOLE-CHEMOPREVENTION |
|---|---|
| Тип | Препарат |
| Синоніми | AI chemoprevention — letrozoleFemaraLetrozole (breast-cancer chemoprevention)Летрозол (хіміопрофілактика раку молочної залози — дослідницько/off-label) |
| Статус | переглянуто 2026-05-18 | очікує клінічного підпису |
| Хвороби | Не вказано |
| Джерела | SRC-NCCN-BREAST-2025 SRC-USPSTF-BREAST-2024 |
Дані про препарат
| Клас | Aromatase inhibitor (non-steroidal, third-generation) |
|---|---|
| Механізм дії | Highly potent reversible non-steroidal inhibitor of cytochrome P450 aromatase (CYP19A1), reducing peripheral conversion of androgens to estrogens. Letrozole 2.5 mg/day suppresses circulating estradiol by >98% in postmenopausal women — the most complete suppression among the three third-generation AIs (anastrozole, letrozole, exemestane). Cancer-prevention rationale: estrogen exposure drives HR-positive breast carcinogenesis; near-total suppression reduces incidence of ER+ breast cancer and DCIS. NO completed primary breast-cancer PREVENTION RCT for letrozole equivalent to IBIS-II (anastrozole) or MAP.3 (exemestane); the AI-class effect supports cross-extrapolation but letrozole-specific prevention evidence is indirect (cross-AI meta-analyses and adjuvant-extension data showing contralateral breast-cancer reduction, e.g., MA.17R Goss NEJM 2016: extended letrozole reduced contralateral pr... |
| Типове дозування | Breast-cancer chemoprevention (off-label, AI class extrapolation — NOT a guideline first-choice): 2.5 mg PO once daily for 5 years. Indicated only for POSTMENOPAUSAL women at increased breast-cancer risk who cannot receive anastrozole or exemestane (e.g., intolerance, drug-interaction profile). Baseline DEXA + lipid panel; vitamin D + calcium supplementation; bone-density re-assessment every 1-2 y. Discontinue and refer to endocrinology if osteoporotic fracture occurs. NOT effective in premenopausal women (ovarian aromatase escape). |
| Зареєстровано в Україні | True |
| Відшкодовується НСЗУ | True |
| Остання перевірка для України | 2026-05-18 |
Нотатки
STUB — v0.2 chemoprevention-workstream authoring (batch 2); pending two-Clinical-Co-Lead signoff per CHARTER §6.1 dev-mode. BREAST-CANCER CHEMOPREVENTION CONTEXT — distinct from generic DRUG-LETROZOLE (treatment indications for postmenopausal HR+ breast cancer + ovulation induction). EVIDENCE WEAKER than anastrozole/exemestane: no completed primary-prevention RCT for letrozole equivalent to IBIS-II or MAP.3; reliance on AI-class extrapolation and contralateral- breast-cancer reduction in adjuvant trials (e.g., MA.17R Goss NEJM 2016 extended-adjuvant letrozole). USPSTF 2024 (Grade B) supports AI chemoprevention in general but cites anastrozole/exemestane as evidence-supported agents. NCCN Breast 2025 lists letrozole as an AI option, with anastrozole/exemestane preferred. Engine should prefer DRUG-ANASTROZOLE-CHEMOPREVENTION or DRUG-EXEMESTANE chemoprevention over letrozole unless documented intolerance or interaction. Surface only after (a) postmenopausal confirmed, (b) high-risk calculator met, (c) baseline bone-health assessment, (d) preference for letrozole specifically documented. Two-Clinical- Co-Lead signoff required before clinical surfacing. Primary AI-class evidence (IBIS-...
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