Pilot study probes earlier markers of doxorubicin cardiac injury in dogs

An exploratory study published in Veterinary Sciences suggests that circulating cardiac biomarkers, especially H-FABP and cardiac troponin I, may detect doxorubicin-associated myocardial injury in dogs earlier than more conventional monitoring tools. The prospective pilot study followed 14 dogs with hemangiosarcoma receiving doxorubicin and compared biomarker changes with echocardiography and 24-hour Holter monitoring. Investigators reported significant post-treatment increases in H-FABP and troponin I, while NT-proBNP, standard echo variables, and Holter-derived heart rate variability measures did not shift significantly at the group level. (mdpi.com)

That question matters because doxorubicin remains one of veterinary oncology's most effective drugs, but its cardiac risk has never been easy to manage. Earlier canine literature has documented clinical cardiotoxicity in a minority of treated dogs and has repeatedly highlighted the lack of sensitive, practical tools for catching injury before structural or symptomatic disease emerges. Small prior studies have explored troponin, NT-proBNP, and advanced echocardiographic techniques, with mixed results on which markers are most useful and when they should be measured. (pmc.ncbi.nlm.nih.gov)

In the new study, the authors prospectively evaluated dogs before treatment and after doxorubicin exposure, focusing on five monitoring domains: H-FABP, cardiac troponin I, NT-proBNP, conventional echocardiography, and Holter-derived heart rate variability. Their central finding was that H-FABP and troponin I rose significantly after treatment, supporting the idea that biochemical evidence of myocardial injury may appear even when more familiar imaging and rhythm metrics still look stable. At the same time, the paper emphasizes its own constraints: only 14 dogs were included, between-dog variability was substantial, and the design used a single post-treatment assessment, which means transient, delayed, or cumulative cardiac effects could have been missed. (mdpi.com)

The broader literature gives that result some context. A 2016 pilot study similarly suggested that cardiac troponin I may be useful for monitoring dogs receiving doxorubicin, while noting that the optimal timing of measurement remains uncertain. Other reports have found that standard-dose doxorubicin is not always associated with clear evidence of significant myocardial damage in every canine cancer population, underscoring how heterogeneous risk may be across tumor types, cumulative doses, and baseline cardiac status. A larger retrospective analysis also found too little consistent troponin testing to support firm clinical recommendations, even as it confirmed that clinically important cardiotoxicity does occur. (sciencedirect.com)

Direct outside commentary on this new paper was limited in the sources available during reporting, but the study's conclusions align with a wider cardio-oncology trend toward biomarker-based surveillance. In both veterinary and human medicine, anthracycline cardiotoxicity is increasingly understood as a process that may begin at the cellular level before conventional functional decline becomes obvious on imaging. That doesn't mean H-FABP is ready for routine adoption in general practice, but it does help explain why investigators are looking beyond echo alone for earlier warning signals. (mdpi.com)

Why it matters: For veterinary professionals, the practical takeaway is cautious, not disruptive. This study does not establish a new standard of care, and it does not show that H-FABP-guided monitoring improves outcomes. What it does offer is another piece of evidence that relying only on conventional echocardiography or Holter data may underestimate early anthracycline-related injury in some dogs. For referral oncology teams, that may support more nuanced discussions with pet parents about cardiac surveillance, especially in dogs with preexisting heart disease, breed-related concerns, or treatment plans that increase cumulative anthracycline exposure. For general practitioners involved in shared care, it is a reminder to watch for subtle cardiac changes and to coordinate closely with oncology and cardiology colleagues when troponin or other biomarkers begin to trend upward. (mdpi.com)

What to watch: The key unanswered questions are whether H-FABP outperforms troponin in real-world monitoring, what sampling schedule is most informative, and whether biomarker elevations predict clinically meaningful endpoints such as reduced systolic function, arrhythmias, treatment modification, or heart failure. Larger prospective studies, ideally with serial measurements across multiple doxorubicin cycles and correlation to cumulative dose and outcomes, will determine whether this remains an interesting pilot signal or becomes a clinically useful monitoring strategy. (mdpi.com)