Adjuvant trastuzumab provides substantial benefits to patients with human epidermal growth factor receptor 2 positive breast cancer, but competing immediate and long-term cardiovascular risks are a great concern, so continued cardiac follow-up of these women is of critical importance.
Such are the conclusions of a paper published in the Journal of Clinical Oncology.
The research assessed the spectrum and reversibility of cardiotoxicity observed in the following adjuvant trastuzumab trials:
• National Surgical Adjuvant Breast and Bowel Project (NSABP) B-31.
• North Central Cancer Treatment Group N9831.
• Herceptin Adjuvant Breast Cancer International Research Group 006.
• Finland Herceptin trials.
The following findings were reported:
• Up to 4% of patients enrolled in the adjuvant trials experienced severe congestive heart failure during treatment.
• Early-stopping rules in the trials that identified an unacceptable level of cardiotoxicity were never reached, but despite this a large number of patients on these trials experienced some form of cardiotoxicity that ultimately required discontinuation of trastuzumab.
• Some 14% of patients in the NSABP B-31 trial discontinued trastuzumab because of asymptomatic decreases in left ventricular ejection fraction (LVEF).
• Results of follow-up cardiac evaluations of patients diagnosed with any degree of cardiotoxicity in the NSABP B-31 trial document that a clinically significant proportion of patients have sustained decreases in their LVEF to <50%.
J Clin Oncol 2007;25:3525-33