Abstract P2-11-16: Cardiac Morbidity After Adjuvant Chemotherapy (CT) for Early Breast Cancer in the Community Setting.

Abstract

Abstract Cardiac morbidity after exposure to CT is a known and previously described risk. Anthracycline exposure can be complicated by acute or chronic cardiac toxicity. Trastuzumab exposure is largely associated with acute and reversible cardiac morbidity. Methods: We retrospectively queried the electronic health record (EHR) from our network of community oncology practices, iKnowMed, for patients (pts) diagnosed with Stage I-III breast cancer (BC) from 2007–2010 with at least 5 visits and follow-up (f/u) through 2012. We stratified this group by CT utilization (yes/no), regimen type, age, and characterized the incidence of cardiac disease or initiation of cardiac medication through the f/u period to determine the association of cardiac disease or treatment with CT utilization. Cardiac diseases analyzed included congestive heart failure, valvular and ischemic heart disease, arrythmias, and hypertension. Cardiac medications included beta blockers, angiotensin-converting-enzyme inhibitors, angiotensin receptor II blockers, loop and thiazide diuretics. Hazard ratios by prespecified risk parameters were then analyzed by multivariate analysis for all pts who did not have cardiac disease preceding their diagnosis of BC. Results: We identified 20,900 pts with a median f/u of 3.2 yrs (1.4–5.4). 11,295 (54%) pts received adjuvant CT and 9,605 (46%) did not. Median age at diagnosis in the CT-treated arm and non CT-treated arm was 54 and 64 yrs, respectively (p < 0.0001). Among both the non-CT and CT-treated group, the baseline prevalence of cardiac disease was 14%. Among the CT-treated group, 3475 pts or 31% (95% CI, 30 %−32%) had or developed cardiac disease within the study period. In the non-CT group, 3790 pts or 39% (95% CI, 38%−40%) had or developed cardiac disease with the study period (p < 0.01). Receiving CT conveyed a lower risk of cardiac morbidity overall, HR 0.86 (p < 0.01). Incidence of cardiac disease was higher among pts who were in the non-CT treated arm (39%) than among the various CT-treated arms: anthracycline and trastuzumab (30%), anthracycline without trastuzumab (26%), non-anthracycline with trastuzumab (33%), and non-anthracycline without trastuzumab (34%). Incidence of cardiac disease increased proportionally over time in all age groups as expected in both cohorts. Conclusions: Age was a strong determinant of development of cardiac morbidity. Adjuvant CT did not increase the risk of cardiac morbidity compared to pts who did not receive CT in the community setting. Similarly, anthracycline and trastuzumab exposure did not increase cardiac morbidity when compared to no CT or other CT regimen types. While baseline cardiac comorbid illness was similar among both cohorts, the lack of increase in cardiac morbidity among pts who received CT may be due to confounding factors such as comorbid illness and age as they are often determinants of appropriate CT utilization. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-11-16.