Risk of congestive heart failure in women treated with trastuzumab (Herceptin) and combination chemotherapy for early-stage breast cancer did not increase over time according to a five-year follow-up of National Surgical Adjuvant Breast and Bowel Project (NSABP) trial B-31, presented at the annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago.
Based on the findings, the research team developed a prediction model to help oncologists assess the risk of heart failure in individual breast cancer patients prior to treatment with Herceptin and chemotherapy.
Their findings will be announced at the Women?s Cancers press briefing at the meeting and published in Abstract LBA513 in the ASCO proceedings.
?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., study presenter and 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 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 compared between the two groups. Initial three-year follow-up results reported that although Herceptin provides a clear and notable benefit to women with HER-2 positive breast cancer, it also causes an increased risk for congestive heart failure ? a 4.1 percent incidence of congestive health failure was reported in the Herceptin and chemotherapy group compared to a 0.8 percent increase in the control group.
The current study found that after five years follow-up, the incidence of congestive heart failure was virtually unchanged ? 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. Congestive heart failure was measured using a Multiple Gated Acquisition scan, or a MUGA scan ? a noninvasive tool that produces a moving image of the beating heart to determine the health of the cardiac ventricles.
The research team also identified possible risk factors for breast cancer patients more likely to develop congestive heart failure from adding Herceptin to combination chemotherapy. They developed a prediction model based on these factors, including hypertension, age and baseline cardiac function.
?It is our hope that this model will help to individualize care for women in terms of choice of Herceptin-containing treatment regimens based on their personal risk and benefits,? said Dr. Rastogi.