Abstract P5-08-17: Monitoring for cardiotoxicity in early breast cancer: an Australian experience
Authors: Kirwin Brendan , Pugliano Lina , Hay Sally Baron 
Published: March 2023

Abstract
Background Breast cancer is the most commonly diagnosed cancer in Australia. Patient outcomes continue to improve with current 10 year survival of 86%. Given this, greater focus is needed to minimise potential long term toxicities of prescribed therapies. Anthracyclines and HER2 targeted therapies are commonly prescribed agents for high risk early breast cancers and are associated with acute and long term cardiotoxicity. Despite this, screening of cardiotoxicity in Australian patients receiving these therapies remains variable due to a lack of endorsed national screening guidelines. We conducted a retrospective review of screening procedures for cardiotoxicity in 2 major oncology centres in metropolitan Sydney and compared the findings to current international recommendations from ASCO/ESMO guidelines. Methods Patients were included if they received doxorubicin, epirubicin or trastuzumab with neoadjuvant or adjuvant intent during 2021. Baseline patient and tumour characteristics including cardiovascular risk factors were reviewed. Baseline ECG, transthoracic echocardiogram (TTE) or cardiac biomarkers (cardiac troponin or brain natriuretic peptide) were recorded, as well as frequency of serial monitoring and incidence of cardiotoxicity and cardiology referrals. Results 111 patients receiving initial curative therapy were included of which 45 received anthracycline therapy without trastuzumab. 66 received trastuzumab of which 34 also received anthracycline. 38 patients were aged greater than 60 and 31 had 2 or more cardiovascular risk factors. Of the patients receiving anthracycline only, 96% had a baseline TTE. All patients receiving trastuzumab only had a baseline TTE and of the 34 patients who received anthracycline and trastuzumab 3 did not undergo baseline TTE but underwent one prior to commencing trastuzumab. 3 patients total had a baseline ECG. No patients had baseline biomarkers measured. Only 5 patients had biomarkers measured at 1 year and all 5 had developed grade 1 heart failure on treatment. These 5 patients were referred for cardiology review and 2 required an interruption of trastuzumab. All patients receiving trastuzumab underwent 3 monthly TTEs on treatment. Of the 35 patients now more than 1 year post treatment completion, only 3 patients had a TTE at 12 months. No patients referred to cardiology have reached 12 months post treatment. Discussion International guidelines recommend screening to identify and treat early cardiotoxicity and prevent long term morbidity. ASCO and ESMO guidelines both recommend patients receiving anthracycline undertake a TTE at baseline and at 6-12 months after completing therapy. Both recommend 3 monthly TTEs for patients receiving trastuzumab. The ESMO guidelines recommend a baseline ECG and consideration of further TTE at 2 years post therapy. For high risk patients the ASCO guidelines discuss offering routine TTEs during treatment. The ESMO guidelines recommend measurement of cardiac biomarkers for patients receiving anthracycline prior to each cycle and routine monitoring can be considered for patients receiving anti HER2 therapy. The ASCO guidelines reserve use of cardiac biomarkers for patients who develop signs or symptoms of cardiac dysfunction. Our study demonstrates that while baseline cardiac assessment is well performed a personalised approach to cardiac monitoring during curative therapy is not. These were unexpected findings given both treatment units are located in well resourced areas of Sydney. An outcome of this study has been the development of a cardio-oncology group within our oncology and cardiology departments. This has led to the development of new clinical guidelines to screen and manage high risk breast cancer patients receiving cardiotoxic therapies. This has empowered patients, care coordinators and physicians to proactively manage cardiac risks from therapy and we hope these institutional guidelines will be adopted nationally.
Citation Format: Brendan Kirwin, Lina Pugliano, Sally Baron Hay. Monitoring for cardiotoxicity in early breast cancer: an Australian experience [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-08-17.