Objective   To investigate long-term cardiotoxicity in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer treated with trastuzumab.

  Methods   We gathered operable, HER2-positive breast cancer patients in Tongji Hospital from January 2002 to January 2005. HER2 positive was defined protein expression (3+) measured by immunohistochemistry or Her2 gene amplification by fluorescence in situ hybridization. A total of 26 cases received 6 mg/kg of trastuzumab every 3 weeks after a loading dose of 8 mg/kg. The left ventricular ejection fraction (LVEF) was measured for regular monitoring and assessment of cardiotoxicity.

  Results  All cases were followed up 79 months to 104 months after the first trastuzumab administration. The median follow-up time was 90 months. Two patients were treated with trastuzumab for less than 1 year, 14 cases were treated for 1 year, and 10 cases were treated for 2 years. A symptomatic decline in LVEF occurred in 2 cases, representing a decrease of more than 10%. In addition, 1 case with hypertension manifested symptoms of heart failure and an LVEF value at 41% after 1 year of cardiac treatment. Comparison between adjuvant chemotherapy with anthracycline and chemotherapy without anthracycline obtained the baseline mean LVEF value of 64.38%± 5.25%. The value was 61.58% ± 4.97% after 1 year of trastuzumab treatment and 60.04% ± 5.73% after 5 years of trastuzumab treatment (P > 0.05).

  Conclusion   Trastuzumab administration was generally safe, with reversible cardiac toxicity. However, this treatment should be evaluated and monitored in elderly breast cancer patients with hypertension and heart disease.