Abstract P3-12-11: Cardiac toxicity in breast cancer patients: A single centre, retrospective review
Authors: Rushton Moira , Crawley Freya , Sulpher Jeffrey , Dent Susan 
Published: May 2015

Background: While advances in breast cancer treatment, including targeted therapies (e.g trastuzumab) have improved patient outcomes, such treatments may also be associated with both short and long term toxicity. In 2008, the Ottawa Hospital Cardiac Oncology Clinic (COC) was established with the goal of providing timely access and care to cancer patients experiencing cancer therapy-related cardiac toxicity. The purpose of this observational study is to review demographics, baseline characteristics, referral patterns and clinical outcomes of breast cancer patients referred to a dedicated COC.

Methods: Breast cancer patients referred to the COC between October 2008 and December 2012 were reviewed. Data collected included: age, sex, date of diagnosis, date of referral to COC, stage of breast cancer at diagnosis and referral, cardiac history, medications, cancer therapy, treatment delays and completion rates, cardiac complications, cardiac test results and cardiology interventions. Descriptive statistical analysis was performed.

Results: 263 breast cancer patients were assessed at the COC (median age = 57; range 23-87). The majority of patients (64%) had early stage (I-II) disease and 215 (81.4 %) of patients had at least one identifiable cardiac risk factor. The most common cardiac risk factors included: smoking (99/263, 37.6%), hypertension (87/263, 33.1%) and dyslipidemia (64/263, 24.3%). Reasons for referral to the COC included reduced left ventricular ejection fraction (LVEF) (137/263, 52.1%) followed by pre-treatment assessment (33/263, 12.5%) and cardiac arrhythmia (21/263, 8.0%). The majority of patients (243/263, 92.4%) received chemotherapy, 188 (77.4%) with first line anthracycline regimens, of those a minority 10/263 (3.8%) stopped chemotherapy for cardiac related toxicity, while 21/263 (8.0%) patients experienced cardiac related chemotherapy delays. The majority of patients 160/263 (60.8%) received first-line trastuzumab and of these, 66/160 (41.2%) suffered cardiac toxicity, 55/66 due to reduced LVEF. 23/160 (14.4%) discontinued therapy due to cardiac toxicity.

164/263 patients were on cardioprotective medications at time of COC referral. 100/263 referred patients had new cardiac medications initiated, most commonly ACE inhibitors (n=67), beta-blockers (n=54) and angiotensin receptor blockers (n =15). 15 patients (5.7%) had invasive testing/procedures, such as cardiac catheterization. After COC assessment/treatment, 117/263 (44.5%) of patients experienced full recovery of LVEF; 27/263 (10.3%) experienced partial recovery, 104/263 (39.5%) had no change, and 13/263 (4.9%) experienced continued decline. 39/263 (14.8%) patients were hospitalized for cardiac toxicity and 3/263 (1.1%) died of cardiac complications. Discussion: While the majority of breast cancer patients referred to a dedicated COC complete systemic therapy, there remains a significant population who require delay or discontinuation of treatment secondary to cardiac dysfunction. Tools to identify patients at higher risk of developing cardiac toxicity are urgently needed, so that appropriate monitoring and treatment can be initiated. Future studies will also determine the impact of this clinic on the delivery of cancer therapy and cardiac health, compared with non-COC referred patients.

Citation Format: Moira Rushton, Freya Crawley, Jeffrey Sulpher, Susan Dent. Cardiac toxicity in breast cancer patients: A single centre, retrospective review [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-12-11.