Minority of Medicare Patients Have Adequate Cardiac Monitoring During Adjuvant Trastuzumab-Based Chemotherapy for Breast Cancer
In a study reported in the Journal of Clinical Oncology, Chavez-MacGregor et al found that the majority of older breast cancer patients receiving trastuzumab (Herceptin)-based chemotherapy do not receive adequate cardiac monitoring.
Study Details
The study involved 2,203 patients aged ≥ 66 years with full Medicare coverage who were diagnosed with stage I to III breast cancer between 2005 and 2009 and treated with adjuvant trastuzumab-based chemotherapy identified from the Surveillance, Epidemiology, and End Results (SEER)–Medicare and Texas Cancer Registry–Medicare databases. Adequate cardiac monitoring was defined as a baseline evaluation (within 4 months before first trastuzumab dose) with echocardiogram or multigated acquisition scan and follow-up evaluation at least every 4 months while receiving trastuzumab therapy. Current guidelines recommend baseline evaluation and evaluation every 3 months during trastuzumab therapy.
Multivariate analysis for factors associated with cardiac evaluation included age, year of diagnosis, race/ethnicity, marital status, education and poverty levels, SEER region, urban/rural area, stage, estrogen and progesterone receptor status, type of surgery, radiation, anthracycline use, taxane use, Charlson comorbidity score, and history of hypertension and coronary artery disease. Physician-related variables included in the multivariate model were decade of graduation, U.S. vs other training location, degree, board certification status, and sex of physician.
Likelihood of Adequate Evaluation
Patients had a median age of 72 years. Adequate monitoring was identified in 793 patients (36.0%). On multivariate analysis, factors associated with optimal cardiac monitoring included more recent year of diagnosis (hazard ratio [HR] = 1.83, 95% confidence interval [CI] = 1.32–2.54), anthracycline use (HR = 1.39, 95% CI = 1.14–1.71), female prescribing physician (HR = 1.37, 95% CI = 1.10–1.70), and physician graduation after 1990 (HR = 1.66, 95% CI = 1.29–2.12). Presence of cardiac comorbidities was not a significant factor in likelihood of cardiac monitoring.
It was estimated that of variance in the adequacy of cardiac monitoring, 15.3% was attributable to physician factors and 5.2% to patient factors.
The investigators concluded: “A large proportion of patients had suboptimal cardiac monitoring. Physician characteristics had more influence than measured patient-level factors in the adequacy of cardiac monitoring. Because trastuzumab-related cardiotoxicity is reversible, efforts to improve the adequacy of cardiac monitoring are needed, particularly in vulnerable populations.”
Mariana Chavez-MacGregor, MD, of The University of Texas MD Anderson Cancer Center, is the corresponding author for the Journal of Clinical Oncology article.
The study was supported by Cancer Prevention and Research Institute of Texas, National Institutes of Health, and Duncan Family Institute. For full disclosures of the study authors, visit jco.ascopubs.org.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
