Cardiac MRI-based Subclinical Cardiac Dysfunction during 2 Years after Breast Cancer Irradiation: The MEDIRAD...

Area of Science:

• Cardiology
• Oncology
• Radiology

Background:

• Breast cancer radiation therapy can impact cardiac function.
• Subclinical cardiac changes are important indicators of potential cardiotoxicity.
• Long-term follow-up is crucial for understanding radiation-induced cardiac effects.

Purpose of the Study:

• To evaluate the relationship between cardiac radiation doses and subclinical changes in cardiac function.
• To assess changes in cardiac function using cardiac MRI over a 2-year follow-up.
• To identify adverse subclinical cardiac changes in breast cancer patients treated with radiation therapy.

Main Methods:

• Prospective multicenter study (NCT03297346) of 138 female breast cancer patients.
• Cardiac MRI performed at baseline, 6 months, and 24 months.
• Assessed whole heart (WH) and left ventricular (LV) radiation doses; defined persistent LV global longitudinal strain (GLS) decrease as an adverse outcome.

Main Results:

• All participants showed reduced LV end-diastolic volume and stroke volume, preserved LV ejection fraction, and increased LV mass/EDV ratio.
• Twenty-three participants (16.6%) had a persistent LV GLS decrease, associated with higher WH and LV radiation doses.
• Higher WH cardiac radiation dose increased the risk of persistent LV GLS decrease (OR, 1.09).

Conclusions:

• A modest, persistent reduction in LV GLS over 2 years is associated with cardiac radiation dose in breast cancer patients.
• Radiation therapy without chemotherapy can lead to subclinical cardiac changes.
• Cardiac MRI is valuable for detecting early signs of cardiotoxicity after radiotherapy.