Statin Therapy Reduces Radiation-Induced Cardiotoxicity in Patients With Breast Cancer Receiving Adjuvant Radiotherapy

BACKGROUND: To evaluate the efficacy of statin therapy in reducing major adverse cardiovascular event (MACE) risk among patients with breast cancer undergoing breast-conserving surgery and adjuvant whole breast radiotherapy. METHODS AND RESULTS: A retrospective cohort study was conducted using data from the Taiwan Cancer Registry Database linked to the National Health Insurance Research Database. Patients diagnosed with left-sided early breast invasive ductal carcinoma between 2016 and 2019 were included. Propensity score matching was employed to compare MACE risk between statin users and nonusers. Cox regression models were used to estimate adjusted hazard ratios (aHRs) for MACE, consider-ing cumulative defined daily doses and daily defined doses of statins. Among 1481 patients undergoing breast-conserving surgery and adjuvant whole breast radiotherapy, statin use significantly reduced MACE risk (aHR, 0.34 [95% CI, 0.25–0.44]). Hydrophilic statins, particularly rosuvastatin and pravastatin, demonstrated the greatest risk reduction. Higher cumulative defined daily doses and daily intensity doses of statins were associated with lower MACE risk, indicating a dose–response relationship. The 5-year cumulative incidence of MACE was significantly lower in statin users compared with nonusers (12.24% versus 31.70%). CONCLUSIONS: Statin therapy is associated with a reduced risk of MACE in patients with breast cancer undergoing breast-conserving surgery and adjuvant whole breast radiotherapy. Hydrophilic statins rosuvastatin and pravastatin exhibit the most pronounced cardioprotective effects. These findings suggest a potential role for statins in mitigating cardiovascular complications in this population and highlight the need for further research to optimize statin therapy in survivors of breast cancer undergoing radiotherapy.