Based on emails that I receive from women taking Herceptin (trastuzumab), I know that many have real fears about the drug causing heart damage. The annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago took place recently and some fascinating news was announced there concerning Herceptin.
The risk of congestive heart failure in women treated with Herceptin and combination chemotherapy for early-stage breast cancer did not increase over time, according to a five-year follow-up of the National Surgical Adjuvant Breast and Bowel Project (NSABP) trial B-31.
Based on its findings, the research team has developed a prediction model to help oncologists assess the risk of heart failure in individual breast cancer patients before starting treatment with Herceptin and chemotherapy. (If you are already on this medication, ask your oncologist about this.)
"The information we obtained from this study is essential to understanding women's risks for congestive heart failure associated with adding Herceptin to combination chemotherapy for breast cancer treatment," said Priya Rastogi, M.D., assistant professor, University of Pittsburgh School of Medicine and assistant director of medical affairs, NSABP.
"We're encouraged that we found no increase in heart failure risks [over the] long-term, and now are able to use this knowledge to individualize women's treatment based on their specific cardiac risk factors."
The study assessed cardiac side effects in 1,850 women with HER-2-positive breast cancer — those who have abnormally high levels of the HER2/neu protein — for five years. Study participants were initially randomized to receive four cycles of a standard combination chemotherapy regimen: doxorubicin and cyclophosphamide followed by paclitaxel; or doxorubicin and cyclophosphamide followed by paclitaxel and Herceptin. The incidence of congestive heart failure was then compared between the two groups.
The initial results, from a three-year follow-up study, had revealed that although Herceptin provided a clear and notable benefit to women with HER-2-positive breast cancer, it also caused an increased risk for congestive heart failure: A 4.1 percent incidence of congestive health failure in the Herceptin and chemotherapy group compared to a 0.8 percent increase in the control group.
The current study, however, found that after five years of follow-up, the incidence of congestive heart failure was virtually unchanged in the two groups: 3.8 percent of patients who received Herceptin and chemotherapy experienced congestive heart failure, compared to 0.9 percent of patients in the control group.
The researchers measured congestive heart failure by using a multiple gated acquisition, or MUGA, scan — a noninvasive tool that produces a moving image of the beating heart to determine the health of the cardiac ventricles.
Since it is well known how effective targeted Herceptin therapy has proven to be for increasing survival, this is good news. So ladies, if you are being treated with Herceptin, or about to be, worry less about the side effect of potential heart problems!