Chemotherapy-associated coronary thrombosis presenting as acute coronary syndrome in breast cancer: a case report

Cancer patients face a high risk of thromboembolic complications due to disease-, treatment-, and patient-related factors. Chemotherapy regimens such as anthracyclines and alkylating agents can increase both venous and arterial thrombosis, leading to significant morbidity. A 44-year-old woman with invasive ductal carcinoma of the right breast underwent right mastectomy and received adjuvant chemotherapy with doxorubicin (60 mg/m²) and cyclophosphamide (600 mg/m²). Five days after her second treatment cycle, she presented with chest pain. Electrocardiography showed inferolateral ST-segment elevation, and echocardiography revealed a left ventricular ejection fraction (LVEF) of 38%. Coronary angiography demonstrated total occlusion of the distal left anterior descending and circumflex arteries. She was treated with dual antiplatelet therapy, low-molecular-weight heparin, and a glycoprotein IIb/IIIa inhibitor. Follow-up angiography on day five showed complete thrombus resolution and restoration of TIMI III flow. During long-term follow-up, her left ventricular function recovered (LVEF 50%) and her cancer remained in complete remission. This case illustrates a rare but clinically important complication of adjuvant doxorubicin–cyclophosphamide therapy, presenting as subacute inferolateral myocardial infarction secondary to coronary thrombosis. Awareness of this potential adverse effect and early management are crucial for improved outcomes.