Abstract PS10-48: Cardiovascular (CV) risk profile in patients with estrogen receptor (ER) positive HER2 negative advanced breast cancer (ABC): A retrospective cohort study (CAREB)
Authors: Dent Susan , Broadwater Gloria , Hyslop Terry , Oeffinger Kevin , Khouri Michel , Balu Sanjeev , Kimmick Gretchen 
Published: February 2021

Background: CDK 4/6 inhibitors in patients (pts) with HR+/HER2- ABC has led to significant improvements in clinical outcomes, however our understanding of the impact of these treatments on CV health is unknown. Gains in overall survival should not be offset by increased CV morbidity and mortality; a particular concern given the shared risk factors for both breast cancer and CV disease. Objective: The aim of this study was to describe patient characteristics, treatment patterns and cardiovascular risk factors and disease in pts with ABC treated with endocrine therapy (ET) or ET + CDK 4/6 inhibitor. Methods: We retrospectively studied pts with HR+/HER2- ABC who were receiving first line endocrine therapy. Post-menopausal (PM) women, pre-menopausal women on ovarian suppression (OS), and men were included. Two cohorts were included: Group A - treated with ET alone (2012-2014; prior to US approval of CDK 4/6 inhibitors) and Group B - treated with ET+ CDK 4/6 inhibitor (2015-2017). The following data was extracted from Duke University Health System’s electronic medical record (EPIC) and entered into a REDCap database: demographics, baseline cardiovascular risk factors, and co-morbidities. Pt characteristics are summarized using medians and interquartile ranges for continuous variables and categorical descriptions are summarized using frequencies and percentages. Results: In total 103 patients were included with 57 in Group A (ET alone) and 46 in Group B (ET + CDK 4/6 inhibitor). Median age was 62.0 and 63.5 years in Group A and B, respectively. Fifty-three (93%) of pts in Group A were PM women compared to 37 (80%) PM women and 1 (3%) male in Group B. The groups seemed to be similar in terms of race (white 70% vs 72%), baseline body mass index (28.2 vs 27.6), baseline systolic blood pressure (132.0 vs 135.5) and diastolic blood pressure (79.0 vs 77.5). Similarly, the groups seemed to be similar in baseline hypertension (68% vs 62%); diabetes (23% vs 24%); Hemoglobin A1c (7.2% vs 6.4%) or family history of CV disease (56% vs 55%), Group A versus Group B, respectively. There were slightly more current/past smokers in Group B than Group A (48% vs 35%) and more pts in Group A with a history of hyperlipidemia relative to Group B (52% vs 31%). Conclusions: In this retrospective descriptive cohort study there seemed to be no differences in demographics or baseline CV risk factors between the ET and ET + CDK 4/6 inhibitor cohorts with the exception of more baseline hyperlipidemia in the ET cohort. This might suggest that baseline CV risk factors did not dissuade practioners from prescribing ET + CDK 4/6 inhibitor therapy. We plan to expand our cohort to collect information on type and duration of ET and CDK 4/6 inhibitors, reason for treatment discontinuation, and CV events (eg heart failure, arrhythmias, stroke, myocardial infarction), to better understand the impact that cardiovascular risk factors have on outcomes in breast cancer patients taking ET+ CDk 4/6 inhibitor. Table 1: Demographics and CV risk factors in ABC patients treated with ET or ET + CDK4/6 inhibitor

Median (IQR) unless otherwise indicatedGroup A ET (n=57)Group B ET+ CDK 4/6 inhibitor (n=46)Age median (range)62.0 (27-84)63.5 (30-82)Menopausal status, n (%) Post menopausal Premenopausal + OS Male53 (93) 4 (7) 037 (80) 8 (17) 1 (3)Race, n (%) White Other40 (70) 17 (30)33 (72) 13 (28)Type of Insurance, n (%) Private Medicare Medicare and Private Medicaid Medicaid and Medicare Vererans Sponsored Self-Pay Unknown19 (33) 14 (25) 16 (28) 1 (2) 4 (7) 0 3 (5) 019 (41) 4 (9) 15 (33) 1 (2) 4 (9) 1 (2) 0 2 (4)BMI (kg/m2)28.2 (24.9, 30.6)27.6 (24.4, 34.5)Baseline BP (mmHg) Systolic Diastolic132.0 (118.0, 145.0) 79.0 (73.0, 84.0)135.5 (124.0, 149.0) 77.5 (72.0, 84.0)HgbA1c (%)7.2 (6.4, 7.4)6.4 (5.4, 6.4)CVRF, n (%) Hypertension Diabetes FH CVD Current/past smokers Hyperlipidemia36 (68) 13 (23) 28 (56) 20 (35) 29 (52)28 (62) 11 (24) 22 (55) 22 (48) 14 (31)OS = ovarian suppression; BMI = body mass index; BP = blood pressure; HgbA1c = hemoglobin A1c; CVRF = cardiovascular risk factors; FH = family history; CVD = cardiovascular disease; IQR = Interquartile range

Citation Format: Susan Dent, Gloria Broadwater, Terry Hyslop, Kevin Oeffinger, Michel Khouri, Sanjeev Balu, Gretchen Kimmick. Cardiovascular (CV) risk profile in patients with estrogen receptor (ER) positive HER2 negative advanced breast cancer (ABC): A retrospective cohort study (CAREB) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS10-48.