Anthracyclic (ANT) drugs are widely used for patients with malignant tumors and can markedly prolong the disease-free survival rate of patients. As its clinical application becomes more common, information regarding serious cardiotoxicity as a result of ANT treatment is becoming understood. However, to the best of our knowledge, delayed-onset cardiotoxicity due to ANT use has not been studied sufficiently. The present report describes a 36-year-old male patient who presented to Guiqian International General Hospital (Guiyang, China) with a complaint of dyspnea in the last 10 days. Substantially elevated B-type natriuretic peptide levels and echocardiography showing enlargement of the entire heart, of the patient suggested that severe heart failure was the cause of his symptoms. However, the cause of this potential heart failure was not apparent until the patient was questioned about his cancer treatment history. Following consultation to evaluate the assessment of end-stage heart failure, currently only anti-heart failure treatment and symptomatic treatment can be provided. The present report describes this case and reviews the existing literature to provide a basis for the diagnosis and treatment of patients with delayed-onset heart failure following ANT treatment.

Cardiotoxicity is a serious adverse effect of an anticancer drug, doxorubicin (DOX), which can occur within a year or decades after completion of therapy. The present study was designed to address a knowledge gap concerning a lack of circulating biomarkers capable of predicting the risk of cardiotoxicity induced by DOX. Profiling of 2083 microRNAs (miRNAs) in mouse plasma revealed 81 differentially expressed miRNAs 1 week after 6, 9, 12, 18, or 24 mg/kg total cumulative DOX doses (early-onset model) or saline (SAL). Among these, the expression of seven miRNAs was altered prior to the onset of myocardial injury at 12 mg/kg and higher cumulative doses. The expression of only miR-34a-5p was significantly (false discovery rate [FDR] < 0.1) elevated at all total cumulative doses compared with concurrent SAL-treated controls and showed a statistically significant dose-related response. The trend in plasma miR-34a-5p expression levels during DOX exposures also correlated with a significant dose-related increase in cardiac expression of miR-34a-5p in these mice. Administration of a cardioprotective drug, dexrazoxane, to mice before DOX treatment, significantly mitigated miR-34a-5p expression in both plasma and heart in conjunction with attenuation of cardiac pathology. This association between plasma and heart may suggest miR-34a-5p as a potential early circulating marker of early-onset DOX cardiotoxicity. In addition, higher expression of miR-34a-5p (FDR < 0.1) in plasma and heart compared with SAL-treated controls 24 weeks after 24 mg/kg total cumulative DOX dose, when cardiac function was altered in our recently established delayed-onset cardiotoxicity model, indicated its potential as an early biomarker of delayed-onset cardiotoxicity.