Trastuzumab Use in Breast Cancer: Clinical Issues

John Horton, MB, ChB


Cancer Control. 2002;9(6) 

In This Article

Trastuzumab in Adjuvant Therapy

The effectiveness of trastuzumab plus chemotherapy in patients with HER2-positive metastatic breast tumors,[4] particularly since survival was prolonged, has generated great interest in the adjuvant arena. The largest currently active trials are summarized in Figure 1.

Accrual to these studies has been rapid, with over 1,000 patients having been entered onto many of the studies. An important concern with these studies is, of course, cardiac toxicity, and only patients screened to exclude those with preexisting cardiac problems are entered. Concern was heightened when accrual to arm 3 of the Breast Intergroup Trial N9831 was interrupted in early 2002 because of an apparent excess of cardiac events in that arm of the study. The study protocol safety and monitoring board has since lifted the proscription on case entry, however, suggesting that cardiac events were either not severe or not occurring at high rates or both. In addition, accrual to this protocol will soon include high-risk node-negative patients. Initial reporting on cardiac toxicity from the studies (E. Perez, MD, personal communication, September 2002) indicates that some patients have experienced a minor decline in LVEF after standard-dose doxorubicin plus cyclophosphamide therapy. Overall, the rates of cardiac events from trastuzumab alone or trastuzumab plus chemotherapy in these adjuvant or neoadjuvant studies seem to be low.

Most adjuvant studies in the United States are studying a 1-year duration of trastuzumab treatment, although the HERA study includes an arm with 2 years of treatment. One can speculate if a longer duration of adjuvant therapy should be studied using the example of tamoxifen where a 5-year treatment duration is appreciably superior to 1 year of treatment.[40]


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