Guest blog post by Professor Mike McConnell, Stanford University School of Medicine, USA.

Chemotherapy can injure heart muscle, leading to heart failure, but this damage may not be apparent until many years later. Children receiving chemotherapy are of particular concern, as the risk of heart failure increases as they age into adulthood. A safe, noninvasive method to detect this damage could identify high risk patients and prompt earlier preventive therapy.

In an article published today in Journal of Cardiovascular Magnetic Resonance, researchers from the University of Alberta, Canada present their result from a study looking at MRI of the heart in 30 children two years after chemotherapy. They found changes in the heart muscle even though overall heart function remained normal. Specifically, they found that the MRI signal representing fibrosis, or scarring, was altered, likely a consequence of heart cells dying at the time of the chemotherapy.

This change in MRI signal was greater in children receiving larger dose of chemotherapy and was also associated with thinning of the heart muscle. Importantly, the researchers also compared MRI to ultrasound measurements of the heart. Only the MRI measurements corresponded to exercise capacity and chemotherapy dose, as well as changes in heart structure.

This curative potential of chemotherapy for childhood cancer has enabled survival well into adulthood, with cardiac damage an unfortunate risk. This study provides hope for a method to detect heart muscle damage long before heart failure symptoms develop. Dr. Edythe Tham and Dr Richard Thompson explained, “In childhood cancer survivors, MRI changes were related to anthracycline dose given to the children. These changes are also mirrored by thinning of the heart wall and a reduction in the exercise capacity. By detecting these changes early we can only hope that future research using these techniques may guide early identification and treatment in attempts to delay the onset of heart damage in children who have survived cancer.”