Potential for Significant Cardiovascular Effects with Newer Biologic Therapies
While heart failure is known to be a common complication in older women with breast cancer, another new study just recently published in the Journal of the American College of Cardiology shows the risk for heart failure is even higher in older women with breast cancer treated with trastuzumab.3 This study specifically looked at older women who were treated with trastuzumab, which is used to treat breast tumors that overexpress HER-2.
“Clinical trials exclude older patients with comorbidities,” said lead study author Jersey Chen, MD, Assistant Professor of Cardiology at Yale University School of Medicine, New Haven, Connecticut. “The major clinical trials showed heart failure is an issue but in our study with older women the rates were much higher.”
Dr. Chen and his colleagues used SEER-Medicare data from 2000 through 2007 and identified women who were 67 to 94 years of age with early-stage breast cancer. The group included 45,537 women (mean age: 76.2 years) and the researchers calculated 3-year incidence rates of heart failure or cardiomyopathy. Dr. Chen said compared with patients who received no adjuvant chemotherapy or trastuzumab, the use of trastuzumab was associated with a 14% higher adjusted incidence rate for heart failure or cardiomyopathy over 3 years. The study also showed that older breast cancer patients who received both trastuzumab and anthracycline had a 23.8% higher rate for heart failure or cardiomyopathy, and those treated with anthracycline chemotherapy alone had a 2.1% higher rate of heart failure or cardiomyopathy events over 3 years.
“Patients and doctors need to get more information and they need to know the potential side effects down the road. We may need to do tighter monitoring,” said Dr. Jersey in an interview with ChemotherapyAdvisor.com. “I do think the issue of heart failure will be even greater in the future because of newer cancer agents, and of most concern are the new tyrosine kinase inhibitors like sunitinib. As more of these drugs are introduced into the market the problem is going to get worse.”
Dr. Chen noted that the use of trastuzumab has increased over time from 2.6% of the women who received any adjuvant therapy in 2000 to 22.6% in 2007. Furthermore, h noted studies are now needed that specifically look at newer agents for treating breast cancer and how they may affect rates of heart failure and/or cardiomyopathy. Currently, there is not enough scientific evidence to set up guidelines about cardiac monitoring for breast cancer survivors.
Predicting Chemotherapy-induced Cardiac Damage Through Biomarkers
An effective screening tool for identifying cardiac damage in breast cancer survivors may not be too far off. By using a blend of high-definition cardiac imaging and biomarkers, researchers have now found a way to catch early heart disease damage caused by anthracyclines. Oncologists and cardiologists have teamed up and looked at patients with breast cancer being treated with doxorubicin and found that it may be possible to identify at-risk patients and then introduce cardioprotective agents or therapies.
Investigators at Ohio State University recently conducted a study in which they measured epithelial progenitor cells (EPC), a rare cell type found in the bloodstream that can indicate cardiac reserve. EPC levels already are a well-established predictor of outcomes in individuals who have had heart attacks, but the Ohio researchers are the first to explore their use in predicting which chemotherapy patients may be at highest risk for developing cardiac injury after exposure to anthracyclines. In addition to looking at EPC levels, the researchers also analyzed cardiac function and physical changes to the heart using cardiac magnetic resonance imaging (CMR) as well as measuring blood levels of troponin and brain natriuretic peptide (BNP), which are two biomarkers that indicate cardiac damage.