LAUSR

Abstract A 67-year-old female patient with metastatic endometrial cancer received carboplatin and paclitaxel combination therapy as the first-line treatment due to chronic kidney disease (Cr 1.18 mg/dL, eGFR 35.8 mL/min/1.73m2). Her electrocardiogram and ejection fraction (63.8%) before the start of chemotherapy were normal. On cycle 2 day 11, she had an emergency visit due to persistent severe nausea. Laboratory studies revealed that she had acute kidney injury (Cr 2.45 mg/dL, eGFR 16.1 mL/min/1.73m2), severe electrolyte imbalance (Na 130 mmol/L, K 3.0 mmol/L, Cl 83 mmol/L, corrected Ca 8.6 mg/dL, and Mg 1.4 mg/dL), and no CK elevation (85 IU/L). She was admitted as an emergency case and received intravenous fluids and antiemetic drugs, but response was poor. On cycle 2 day 13, she experienced sudden loss of consciousness. An electrocardiogram showed intermitted torsade de pointe (TdP) and long QT interval (QTc 536 ms), and she was transferred to the coronary care unit. Additional laboratory studies found persistent severe electrolyte imbalance (Na 130 mmol/L, K 2.8 mmol/L, Cl 90 mmol/L, corrected Ca 8.1 mg/dL, and Mg 1.2 mg/dL), no hypothyroidism and reduced left ventricle contraction (ejection fraction 36.2%). Carboplatin can trigger renal tubular dysfunction and electrolyte imbalance. In addition, QTc alterations have been reported with the use of both carboplatin and paclitaxel regardless of electrolyte imbalance. On this basis, a diagnosis of chemotherapy-induced long QT syndrome which led to TdP was made, although the baseline chronic kidney disease might also have been involved. Because of the lack of tumor response and deterioration of general condition, chemotherapy was terminated, and she was transferred to a hospice. The occurrence of TdP is a rare but potentially life-threatening cardiotoxicity. Because many anticancer treatments are known to prolong the QT interval through a variety of mechanisms, clinicians should keep this potential in mind.