Late Anthracycline Induced Cardiotoxicity- Childhood Cancer Survivors

Overview

Anthracyclines treat up to 60% of childhood malignancies with remarkable improvements survival rates. Unfortunately anthracyclines are associated with an increased cardiomyopathy risk. One study showed an almost six-fold greater risk of developing cardiomyopathy compared to sibling controls. A retrospective pilot study showed evidence of subclinical dysfunction (including impaired global longitudinal strain) in 42/52 childhood cancer survivors. There is limited research in this area, therefore current guidelines are based on expert opinion alone and lack consensus. Current methods of detection diagnose cardiomyopathy at an irreversible stage i.e. when the compensatory mechanisms are exhausted and the left ventricular ejection fraction impaired. Small trials have shown that early treatment with standard heart failure therapy may reverse damage, further validation is however required in this cohort. Newer techniques such as tissue doppler and strain rate imaging have shown promise for early prediction of cardiomyopathy in adult studies. Biomarkers such as troponin and NT-proBNP have also shown a correlation with cardiomyopathy. This study (n=208) aims to use echocardiography, strain imaging, holter monitoring and MRI for early detection of cardiomyopathy. Biomarkers, both currently used (for example, troponin and NTproBNP,) and more novel (for example, IL6, MPO, and sST2) will be assessed to see if early cardiomyopathy can be predicted. This study will explore biomarker discovery by analysing an age/gender matched subgroup for the top differentially expressed microRNA and protein biomarkers. Selected biomarkers will then be validated in a larger cohort.

CLINICAL APPOINTMENT A linked anonymised Case Report Form will be completed using participant answers and relevant aspects of their electronic care record. This will involve questions about the patient's demographics, chemotherapy history, cardiac symptoms, past medical history, medication history and family history. Consenting patients will then have * height, weight and blood pressure taken * cardiovascular and respiratory examination Participants will then undergo * SF36 quality of life questionnaire * 6 minute walk test, grip strength * Electrocardiogram by a trained researcher * Venesection- 40ml blood sample from a peripheral vein by the trained researcher Crevicular fluid sample INVESTIGATIONS Participants will be invited for: 1. 24 hour holter monitor- arrhythmia assessment 2. Echocardiogram- diastolic and systolic function assessment, valvular analysis, global longitudinal strain 3. Magnetic resonance imaging (MRI) scan of the heart- volumetric analysis, late gadolinium enhancement and STIR imaging assessments. As part of the scan the patient will require a venflon to be inserted into a peripheral vein for gadolinium injection. A safety questionnaire will be sent to the patient prior to attendance as part of standard MRI procedure. All safety aspects will be re-assessed on the day of attendance by a trained radiographer BLOOD SAMPLE ANALYSIS Blood samples will be sent for standard of care and cardiovascular risk assessment. Tests include a full blood picture, urea and electrolytes, C-reactive protein, iron profile, B12 and folate, lipid profile, HbA1c, NT-proBNP and high sensitivity troponin. Additional disease associated biomarkers for example sST2, MPO, and IL6 will be quantified using immunoassays. Biomarker discovery, including transcriptomics and proteomics will be carried out to identify signatures that could predict cardiotoxicity, subclinical dysfunction, and cardiomyopathy.