Abstract P4-16-12: Does initial cardiac imaging impact clinical outcomes in patients with breast cancer?
Authors: Parent S , Xu L , Becher H , Mackey J , King K , Pituskin E , Paterson I 
Published: May 2019

Background: Echocardiography (echo) and multigated acquisition (MUGA) scans are the most commonly used modalities to assess cardiac function during breast cancer (BC) treatment. However, a case series of 176 patients with cancer suggests enhanced cardiac care with echo surveillance. We hypothesized that patients with early BC imaged by echo have improved cardiac outcomes compared to those imaged by MUGA.

Methods: Consecutive patients with stage I to III breast cancer undergoing pre-treatment echo or MUGA were retrospectively screened from January 2010 to December 2014. Patients participating in clinical trials with mandated imaging and/or cardiac reviews were excluded. Demographics, medical history and clinical events were collected via chart review and electronic health records. All patients had a minimum 1 year of follow-up. The primary outcome was a composite of death, cardiac hospitalization or cardiac emergency room visit.

Results: 598 patients were identified as having a baseline echo and 636 had had baseline MUGA. Mean follow-up was 4.5±1.4 years. Patients undergoing MUGA were younger, had more advanced stage of disease and received more anthracycline and trastuzumab (table1). Patients imaged by MUGA had lower cardiac function at baseline compared to echo, LVEF 64% vs. LVEF 65% respectively, P &lt;0.001. Cancer therapy related cardiac dysfunction was similar between groups, 10% vs. 11%, p=0.81. Patients in the echo group were more likely to be seen by cardiology, 7% vs. 3%, p&lt;0.0001, and to be initiated on beta blocker, 4% vs. 1%, p=0.006, or angiotensin converting enzyme inhibitor, 3% vs. 1%, p=0.002.However, there was no difference between groups for the primary outcome, 10% event rate in each group, even after adjustment for age, BC stage, chemotherapy and cardiac medications, hazard ratio 1.04 (CI 0.72-1.49), p=0.842.

Conclusion: For patients with early stage BC, the choice of cardiac imaging modality at baseline does not impact adverse cardiac events. However, patients undergoing echo were more likely to be evaluated and managed by cardiology.

Table 1.Baseline Characteristics Echo (N=598)MUGA (N=636)Age mean54±1053±10*BMI mean29±629±7Cardiovascular HistoryDiabetes66(11%)56(9%)Hypertension154(26%)155(24%)Dyslipidemia83(14%)75(12%)CAD9(2%)6(1%)CHF7(1%)4(1%)Beta Blocker22(4%)28(4%)ACE-Inhibitor51(9%)64(10%)Angiotensin Receptor Blocker69(12%)44(7%)*Cancer HistoryStage*Stage I65(11%)56(9%)Stage II377(63%)361(57%)Stage III155(26%)219(34%)Receptor StatusTriple negative64(11%)76(12%)HER2 negative, hormone positive342(58%)387(61%)HER2 positive192(32%)173(27%)Cancer TherapyChemotherapy (any)528(88%)594(93%)*Anthracycline310(52%)394(62%)*Trastuzumab170(28%)148(23%)*Anthracycline & trastuzumab6(1%)19(3%)*Hormone therapy459(77%)487(77%)Radiation (any)487(81%)527(83%)Radiation left side237(49%)259(49%)Surgery597(100%)633(100%)* p&lt;0.05 for comparison between echo and MUGA groups

Citation Format: Parent S, Xu L, Becher H, Mackey J, King K, Pituskin E, Paterson I. Does initial cardiac imaging impact clinical outcomes in patients with breast cancer? [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-16-12.