Prospective Multimodal Assessment of Radiation-Induced Subclinical Cardiac Changes in Patients with Left Breast Cancer Using Hematologic Biomarkers, Echocardiography, and 18F-FDG PET/CT: A Pilot Study

Figures

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  Figure 1. Changes in hematologic inflammatory biomarkers before and after breast RT; (a) neutrophil-lymphocyte ratio, (b) platelet-lymphocyte ratio, (c) lymphocyte-monocyte ratio. There were significant changes in all the inflammatory biomarkers before and after breast RT, and they reverted to baseline levels from 3 months to 1 year.

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  Figure 2. Changes in cardiac-specific biomarkers before and after breast RT; (a) troponin T (TnT), (b) N-terminal prohormone of brain natriuretic peptide (NT-pro BNP), (c) soluble suppression of tumorigenicity 2 (sST2). There were significant changes in all cardiac-specific biomarkers before and after breast RT, except for NT-pro BNP. TnT increased immediately and subsequently recovered, whereas sST2 showed the most substantial changes at 6 months post-RT and slightly recovered at the 1-year follow-up.

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  Figure 3. Images of 18F-FDG PET/CT 12 weeks after RT completion in a 46-year-old woman with left breast cancer (a–c). An irradiated area more than 30 Gy is indicated by the pink thin solid line; A segment with an irradiated myocardium more than 30 Gy (irradiated myocardium of 30) is indicated by the blue thick solid line. Less than 30 Gy (non-irradiated myocardium of 30) is indicated by the cyan thin solid line. The metabolic activity of the ‘irradiated myocardium of 30’ is substantially different from that of the ‘non-irradiated myocardium of 30’ after RT.

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  Figure 4. Changes in the SUVmax on 18F-FDG PET/CT before and after breast RT; the ratio of irradiated myocardium to non-irradiated area receiving more than 30 Gy (a) and 47.5 Gy (b). In both groups, statistically significant increases were observed in Pre-RT and Post-2, and between Pre-RT and Post-4, whereas no significant differences were found between Post-2 and Post-4. These findings suggest that metabolic changes in regions receiving more than 30 Gy may persist for up to one year after RT.

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  Figure 5. Axial, coronal, and sagittal images of RT planning (a–c) of a 46−year−old woman with left breast cancer and her bull’s eye plot of echocardiography before (d) and 12 weeks after (e) RT completion; the heart is indicated by the cyan translucent area; the blue translucent area indicates the whole left ventricular myocardium; the irradiated area more than 30 Gy is indicated by the pink translucent area; and the irradiated myocardium more than 30 Gy (irradiated myocardium of 30 Gy) is indicated by the blue thick solid line (a–c). The segments representing the normal strain before RT (d, green circles) were changed to hypokinetic (e, green circles) 3 months after RT, and the segments representing the hypokinetic strain (d, yellow circles) were changed to akinetic (e, yellow circles). The changed segments are mainly the apex, apical−anterior, and mid-anterior regions, corresponding to the irradiated myocardium of the 30 Gy.