Quantitative assessment of early changes in myocardial extracellular volume during postoperative adjuvant chemotherapy in patients with breast cancer via dual-layer spectral detector computed tomography: a cohort study

Background: The major of anticancer therapies induce a wide spectrum of cardiotoxic effects. Early identification of anticancer treatment-associated cardiotoxicity is critical to informing decisions on subsequent interventions. Myocardial extracellular volume (ECV) has been proposed as a useful parameter for quantifying the early cardiotoxicity of cancer-related treatment. This study used dual-layer spectral detector computed tomography (CT) technology to simultaneously assess cardiac function and myocardial ECV, characterizing the early changes in parameters during breast cancer therapy.

Methods: A single-center cohort study was conducted that prospectively enrolled 40 women with breast cancer (mean age 47.5±10.8 years) who underwent postoperative adjuvant chemotherapy between January 12, 2022, and November 2, 2023, with available data from baseline to 3 months after chemotherapy of cardiac computed tomography (CCT), ultrasound cardiography (UCG), electrocardiography, and serum biomarkers. Midventricular and global ECVs of the left ventricle were measured based on an iodine map of the late enhancement phase of dual-layer spectral detector CT. Changes in cardiac function parameters, ECVs, and cardiac biomarkers from baseline to the 3-month follow-up were analyzed. Correlation coefficients between the changes in cardiac function parameters and ECVs were calculated.

Results: Between baseline and 3 months, there was no significant change in left ventricular ejection fraction (LVEF) on UCG (67.1%±3.8% vs. 66.3%±4.3%, P=0.29) or LVEF on CCT (65.4%±5.9% vs. 64.3%±7.4%, P=0.28). Heart rate increased over 3 months of follow-up (75.2±11.5 vs. 81.7±12.3 bpm; P<0.01). After normalization to body surface area (BSA), cardiac output on CCT/BSA ratio (CCT-CO indexed) (3.5±0.6 vs. 3.8±0.6 L/(min·m²); P=0.01) and left ventricular late (active) filling volume/BSA ratio (LVLFV indexed) (13.5±3.7 vs. 15.8±4.2 mL/m²; P<0.01) significantly increased, while there was a significant decrease at the 3-month follow-up in left ventricular early (passive) filling volume/BSA ratio (LVEFV indexed) (33.3±6.6 vs. 30.6±8.2 mL/m²; P=0.01) and LVEFV/LVLFV ratio (2.7±1.1 vs. 2.1±0.9; P<0.01). Midventricular and global ECVs were elevated at 3 months, significantly so for the midanterior ECV (24.0%±4.5% vs. 25.6%±3.1%; P=0.04), midaverage ECV (25.6%±2.5% vs. 27.0%±2.9%; P=0.01) and global ECV (25.4%±2.4% vs. 27.3%±2.7%; P<0.01). Although changes in ECVs were not associated with changes in LVEFs, global ECV changes were moderately correlated with changes in left ventricular end-diastolic volume/BSA ratio (CCT-LVEDV indexed) (r=0.52; P<0.001), left ventricular stroke volume/BSA ratio (CCT-LVSV indexed) (r=0.56; P<0.001), CCT-CO indexed (r=0.40; P=0.01), and LVEFV indexed (r=0.41; P=0.009).

Conclusions: CCT-derived ECV was used to evaluate myocardial changes in the early stage of chemotherapy before LVEF significantly decreased. The increases in ECV were not correlated with LVEF. The changes in myocardial ECVs were moderately correlated with cardiac function parameters. ECV may be a useful biomarker for detecting cardiotoxicity in patients with breast cancer in the early stage of anticancer therapy.