(HealthDay News) — For patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer, trastuzumab improves overall and progression-free survival, according to a review published online June 12 in The Cochrane Library.

Sara Balduzzi, from the University of Modena and Reggio Emilia in Italy, and colleagues conducted a systematic review of the literature to examine the efficacy and safety of therapy with trastuzumab in women with HER2-positive metastatic breast cancer. 

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Data were included from seven published randomized controlled trials (involving 1,497 patients) which compared the efficacy and safety of trastuzumab alone or in combination with chemotherapy, hormone therapy, or targeted agents.

The researchers found that the combined hazard ratios for overall and progression-free survival favored the trastuzumab-containing regimens, with hazard ratios of 0.82 and 0.61, respectively. Trastuzumab was associated with increased risk of congestive heart failure and with left ventricular ejection fraction decline (relative risks, 3.49 and 2.65, respectively).

Trastuzumab seemed to raise the risk of neutropenia, although there was no clear evidence that the risks of hematological toxicities differed between the groups.

“Trastuzumab improved overall survival and progression-free survival in HER2-positive women with metastatic breast cancer, but it also increased the risk of cardiac toxicities,” the researchers wrote. “Studies that administered trastuzumab as first-line treatment, or along with a taxane-based regimen, improved mortality outcomes.”

RELATED: Incidence of Cardiac Events Low With Adjuvant Trastuzumab

All trials in the review were funded by the pharmaceutical industry; one review author and the editorial author disclosed financial ties to pharmaceutical companies, including ones that manufacture and market trastuzumab.

“Overall, this review confirms the impression of clinicians who treat breast cancer that trastuzumab is a very effective treatment for women with metastatic HER2-positive breast cancer, but one needs to be careful about heart function,” the author of an editorial wrote.

“Future updated reviews may have the opportunity to review non-randomised studies, specifically to examine and perhaps more accurately quantify any toxic effects of trastuzumab. Meanwhile, other drugs targeting HER2 are being tested in clinical trials and will be the subject of further systematic reviews.”


  1. Balduzzi S, Mantarro S, Guarneri V et al. Trastuzumab-containing regimens for metastatic breast cancer. Cochrane Database Syst Rev. 2014;doi:10.1002/14651858.CD006242.pub2.
  2. Wilcken N. Treating Metastatic Breast Cancer: The Evidence for Targeted Therapy. Cochrane Database Syst Rev. 2014;(6):ED000083.