Definition
Cardiotoxicity = adverse effects of anticancer therapies on the cardiovascular system, leading to structural or functional heart damage.
It can manifest as arrhythmias, ischemia, hypertension, left ventricular dysfunction, or heart failure.
Types of Cardiotoxicity
- Type I (Irreversible)
- Example: Anthracyclines (doxorubicin, daunorubicin, epirubicin, idarubicin)
- Mechanism: Free radical formation → oxidative stress → myocyte necrosis → permanent damage.
- Cumulative dose-dependent (e.g., doxorubicin >450–550 mg/m² increases risk).
- Type II (Reversible)
- Example: Trastuzumab, pertuzumab (HER2 inhibitors)
- Mechanism: Interference with HER2 signaling needed for cardiomyocyte survival.
- Usually reversible upon discontinuation.
Oncologic Agents Associated with Cardiotoxicity
| Drug/Class | Mechanism of Cardiotoxicity | Manifestations |
|---|---|---|
| Anthracyclines (Doxorubicin, Daunorubicin, Epirubicin, Idarubicin) | ROS generation, mitochondrial injury | Irreversible cardiomyopathy, CHF (dose-dependent) |
| HER2-targeted agents (Trastuzumab, Pertuzumab, Ado-trastuzumab emtansine) | Inhibition of HER2 cardiac survival signaling | LV dysfunction, CHF (reversible) |
| Alkylating agents (Cyclophosphamide, Ifosfamide) | Endothelial damage, free radicals | Hemorrhagic myocarditis, pericarditis, arrhythmias |
| Antimetabolites (5-FU, Capecitabine) | Coronary vasospasm | Angina, MI, arrhythmias |
| TKIs (e.g., Ponatinib, Sunitinib, Sorafenib, Pazopanib) | VEGF inhibition → hypertension; off-target kinase effects | Hypertension, LV dysfunction, ischemia, QT prolongation |
| Immune Checkpoint Inhibitors (e.g., Nivolumab, Pembrolizumab, Ipilimumab) | Autoimmune myocarditis | Myocarditis, arrhythmias, pericarditis |
| Radiation therapy (mediastinal) | Microvascular and valvular damage | CAD, valvular disease, restrictive cardiomyopathy, pericarditis |
Clinical Manifestations
- Acute: Arrhythmias, myocarditis, pericarditis (rare, during or shortly after infusion).
- Chronic: Left ventricular dysfunction, cardiomyopathy, congestive heart failure (months–years later).
- Late effects: Accelerated atherosclerosis, valvular disease (especially after chest radiation).
Monitoring & Prevention
- Baseline Assessment:
- Echocardiogram (LVEF via ECHO or MUGA scan) before anthracyclines or trastuzumab.
- ECG for QT prolongation risk with TKIs.
- During Therapy:
- Repeat echocardiography every 3–6 months in high-risk patients.
- Monitor biomarkers (troponin, BNP) in select patients.
- Prevention Strategies:
- Limit cumulative anthracycline dose.
- Use liposomal doxorubicin (reduced cardiac exposure).
- Use dexrazoxane (cardioprotectant for anthracycline-induced cardiotoxicity).
- Optimize risk factors (HTN, diabetes, smoking).
- Avoid concurrent cardiotoxic agents if possible.
Role of the Oncology Pharmacist
- Risk assessment: Identify high-risk patients (elderly, pre-existing heart disease, prior anthracyclines, mediastinal radiation).
- Drug selection & dosing:
- Recommend liposomal formulations or dexrazoxane when appropriate.
- Dose adjustments if cardiac dysfunction develops.
- Monitoring:
- Flag patients for ECHO/QT monitoring.
- Watch drug–drug interactions (e.g., TKIs + QT-prolonging drugs).
- Patient counseling:
- Educate on early signs: dyspnea, edema, palpitations, chest pain.
- Collaboration: Work closely with cardio-oncology teams.
Summary
Cardiotoxicity in oncology can be dose-dependent (anthracyclines), reversible (trastuzumab), or immune-mediated (checkpoint inhibitors). Pharmacists play a vital role in prevention, monitoring, and patient safety through risk stratification, drug optimization, and counseling.
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