Findings from an international clinical trial suggest a new treatment option for some women with aggressive types of breast cancer. In the trial, women treated with trastuzumab (Herceptin) and chemotherapy before surgery (neoadjuvant) and trastuzumab again after surgery (adjuvant) had a reduced risk of the disease recurring or progressing after 3 years compared with women who received pre-surgical chemotherapy but no trastuzumab. The findings were published in the January 30, 2010, Lancet.
The 230 women enrolled in the trial had either locally advanced or inflammatory breast cancer that was HER2-positive. Although trastuzumab has been shown to improve overall survival in women with HER2-positive early stage and metastatic breast cancer, the drug has not been closely studied in women with these intermediate stages of breast cancer, the research team wrote.
Patients who were randomly assigned to receive trastuzumab took the drug for a total of 1 year. Three-year event-free survival—with an event defined as disease recurrence, progression, or death from any cause—was 71 percent in patients treated with trastuzumab and 56 percent in those who did not receive it. The pathologic complete response rate, or no detectable presence of cancer, was nearly doubled among the women who received trastuzumab.
To date, there is no statistically significant improvement in overall survival among the women who received trastuzumab. This could be due to the fact that 17 percent of the women in the chemotherapy-alone arm also received adjuvant trastuzumab, while some other patients received the drug following a recurrence, explained the trial’s principal investigator, Luca Gianni, M.D., of the Italian National Cancer Institute, in a Lancet podcast.
There were no significant issues with cardiac side effects, which have been a recurring problem in other breast cancer trials involving trastuzumab and doxorubicin , a drug that was part of the chemotherapy regimen used in the trial.
According to Massimo Cristofanilli, M.D., chair of the Department of Medical Oncology at Fox Chase Cancer Center, pathologic complete response “is the most important prognostic factor” in women with these breast cancer types. The low rates of cardiac side effects, he noted, were likely due to the fact that patients in the trial had not been pretreated, had optimal heart function, and the cumulative doses of doxorubicin were below those typically associated with cardiotoxicity.