Abstract P5-13-07: Tolerance of HER-2 directed therapy for early stage breast cancer in a predominantly Hispanic population with high prevalence of cardiovascular risk factors
Authors: Gaur S , McAlice M , Alshaban A , Mahfoud A , Corral J , Philipovskiy A 
Published: May 2019

Introduction:

Trastuzumab based therapy is recommended for patients with early stage HER-2 overexpressing breast cancer, because it improves survival. Significant racial disparities exist in the receipt of trastuzumab with minorities being 25% less likely than whites in being treated with it. (Reeder-Hayes K et al, JCO 2016; 34:2003-2009).

Trastuzumab can affect cardiac function. Cardiac complications associated with trastuzumab are influenced by age and pre-existing risk factors including obesity, hypertension and diabetes mellitus. These co-morbidities occur more frequently in medically underserved minority populations and might influence the practitioner's decision regarding withholding the drug.

We previously identified a high prevalence of metabolic syndrome and obesity in our predominantly Hispanic, medically underserved patient population (SABCC 2015 abstract P1-09-07)). For this study, we analyzed the echocardiographic data and cardiac complications associated with trastuzumab use in this patient population.

Methods:

All patients diagnosed with early stage (stage 1, 2 or 3) HER 2 positive breast cancer between Jan 1st, 2010 and Jan 1st, 2015 at our institution were identified. Age, race, body mass index, pre-existing cardiovascular risk factors, and antihypertensive medication use was collected. Tumor size, nodal status, ER, PR and HER 2 status was recorded. All echocardiograms obtained were reviewed for ejection fraction changes. Repeated measures one sided ANOVA was used to analyze changes in EF. Hospitalization for cardiac complications was recorded. Early interruption of planned therapy and its reasons were recorded. Study was approved by the institutional IRB.

Results:

Sixty patient were treated with trastuzumab based chemo immunotherapy over the study period. 93% were Hispanic, median age was 61 years (Range 31-83), 40% had hypertension, 35% had dyslipidemia, 35% had glucose intolerance or type II diabetes mellitus and 70% were overweight or obese. 33% were dependent on charity care. 26% had stage 1, 37% had stage 2 and 37% had stage 3 cancer. Docetaxel, carboplatin, trastuzumab (TCH) was the most commonly used regimen (63%) followed by doxorubicin, cyclophosphamide, paclitaxel and transtuzumab (28%).

Ten patients (16.6%) required early discontinuation of cytotoxic chemotherapy. Only 1 patient was unable to complete planned 1 year of trastuzumab due to declining ejection fraction. There were no hospitalizations related to cardiac events during therapy.

Trastuzumab based treatment elicited statistically significant changes in LVEF over time, F (2,98) =13.974, p&lt;.0005, with LVEF decreasing from 65.4±.844 prior to therapy to 64.7±.724 during 3-6months of therapy and 62.2±.81 at the end of therapy. Two patients had a decline in LVEF ≥ 10%. Of these, 1 resolved at follow up ECHO in 6 weeks.

Conclusion

In a predominantly Hispanic, HER 2+ breast cancer cohort, with a high prevalence of cardiovascular risk factors and limited health care access, we found that the vast majority were able to complete 1 year of trastuzumab without significant cardiac complications. As trastuzumab improves survival, practitioners should adhere to national guidelines regarding its use as much as possible.

Citation Format: Gaur S, McAlice M, Alshaban A, Mahfoud A, Corral J, Philipovskiy A. Tolerance of HER-2 directed therapy for early stage breast cancer in a predominantly Hispanic population with high prevalence of cardiovascular risk factors [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 P5-13-07.