Data from the St. Jude lifetime cohort study (St. Jude LIFE) revealed that two common biomarkers of cardiac function and damage could better predict cardiomyopathy within five years than routine clinical evaluations in high-risk, asymptomatic childhood cancer survivors. Early detection through screening using these two biomarkers may lead to earlier treatment to prevent and protect against further heart damage. The findings were published today in the Journal of Clinical Oncology.
Cardiomyopathy is often asymptomatic at onset and thus “invisible” to routine clinical evaluations. St. Jude Children’s Research Hospital scientists found that two common biomarkers, global longitudinal strain (GLS) and N-terminal-pro-B-type natriuretic peptide (NT-proBNP), could identify survivors with otherwise normal appearing heart function who are at elevated risk of decline in heart muscle function.
The results showed an increase in predicting asymptomatic heart damage in patients treated with potent anthracycline chemotherapy drugs, such as doxorubicin. The study found that these biomarkers did not improve prediction models in patients who only received radiation. This knowledge may help physicians limit testing to only anthracycline-exposed survivors, saving time and resources while maximizing utility.
“This means doing more for patients at greatest risk while avoiding unnecessary tests for patients who will not benefit from them,” Ehrhardt said.
Two signs point to invisible heart problems
The key to helping survivors with asymptomatic cardiomyopathy is to detect dysfunction early. Cardiac function is typically assessed using echocardiograms, which look at the volume of blood pumped through part of the heart. The most common measure of that volume is called left ventricular ejection fraction. Many childhood cancer survivors appear to have a normal ejection fraction, only to later develop cardiomyopathy. Findings showed that even in survivors with normal ejection fraction, abnormal GLS and NT-proBNP improved the ability to predict cardiomyopathy risk.
“A survivor with a normal ejection fraction at baseline with abnormal ranges of both biomarkers was at a fourfold increased risk for a worsening ejection fraction in the next five years,” Ehrhardt said.
GLS is an additional measure of heart function obtained from an echocardiogram. GLS is more sensitive for detecting cardiac muscle injury than the traditionally reported ejection fraction. It is a software-derived mathematical estimation of the heart muscle fibers’ ability to contract, rather than the more rudimentary measure of ejection fraction, or blood volume pumped at a specific time. An institution that performs echocardiograms to measure ejection fraction can theoretically also routinely measure GLS.
NT-proBNP is a serum biomarker, a chemical released into the bloodstream in greater quantities when the heart is injured or overworked. It is frequently used in adult cardiac patients to identify potential heart injury and is thus widely available, though its application in pediatric oncology is relatively novel.
Practical measures to predict and protect the heart earlier
“One of the promising aspects of our findings is that both of these measures are readily available and, therefore, have the potential to impact care more immediately. Most cardiologists are already using GLS,” Ehrhardt said, “and NT-proBNP has been around for a long time.”
Together, these two common and easy-to-implement measures may help identify survivors at elevated risk of cardiomyopathy earlier, leading to earlier therapeutic interventions. Early detection helps protect against cardiac damage in adults with other diseases; it may extend the same benefits to childhood cancer survivors.
Authors and funding
The study’s other authors are Qi Liu, University of Alberta; Isaac B. Rhea, University of Tennessee Health Science Center; Daniel Mulrooney, Stephanie Dixon, John Lucas, Yadav Sapkota, Kyla Shelton, Kirsten Ness, Deo Kumar Srivastava, Aaron McDonald, Leslie Robison, Melissa Hudson, Yutaka Yasui and Gregory Armstrong, of St. Jude.
The study was supported by grants from the National Cancer Institute (Cancer Center Support (CORE) grant (P30CA21765), U01CA195547 and R01CA216354) and ALSAC, the fundraising and awareness organization of St. Jude.
St. Jude Children's Research Hospital
St. Jude Children's Research Hospital is leading the way the world understands, treats and cures childhood cancer, sickle cell disease and other life-threatening disorders. It is the only National Cancer Institute-designated Comprehensive Cancer Center devoted solely to children. Treatments developed at St. Jude have helped push the overall childhood cancer survival rate from 20% to 80% since the hospital opened more than 60 years ago. St. Jude shares the breakthroughs it makes to help doctors and researchers at local hospitals and cancer centers around the world improve the quality of treatment and care for even more children. To learn more, visit stjude.org, read St. Jude Progress blog, and follow St. Jude on social media at @stjuderesearch. (VP/Newswise)
