Table 2.
Baseline characteristics, cardiac doses, GLS and ST2 levels compared according to the >15% (group 1) and ≤15% (group 2) relative change in GLS.
| Group 1 (n = 14) | Group 2 (n = 47) | p | |||
|---|---|---|---|---|---|
| Baseline characteristics | |||||
| Age, Md (IQR) | 67.0 | (59.0–73.5) | 64.0 | (58.0–66.0) | 0.049 |
| BMI, Md (IQR) | 28.8 | (24.8–30.7) | 25.8 | (23.9–27.7) | 0.081 |
| Left-sided BC, n (%) | 14 | (100.0) | 35 | (74.5) | 0.052 |
| AI, n (%) | 9 | (64.3) | 11 | (23.4) | 0.008 |
| Tam, n (%) | 0 | (0.0) | 6 | (12.8) | 0.321 |
| Hypertension, n (%) | 5 | (35.7) | 18 | (38.3) | 1.000 |
| ACE, n (%) | 3 | (21.4) | 13 | (27.7) | 0.742 |
| Beta-blockers, n (%) | 4 | (28.6) | 7 | (14.9) | 0.256 |
| ASA, n (%) | 1 | (7.1) | 4 | (8.5) | 1.000 |
| Statins, n (%) | 2 | (14.3) | 10 | (21.3) | 0.715 |
| CAD, n (%) | 1 | (7.1) | 2 | (4.3) | 0.549 |
| Diabetes, n (%), n = 14 and 44 | 1 | (7.1) | 3 | (6.8) | 1.000 |
| Smoking, n (%) | 1 | (7.1) | 5 | (10.6) | 1.000 |
| Hypothyreosis, n (%) | 4 | (28.6) | 6 | (12.8) | 0.245 |
| Radiation doses to the heart | |||||
| Dmean heart ≥2 Gy, n (%) | 11 | (78.6) | 23 | (48.9) | 0.068 |
| Dmean heart (Gy); Md (IQR) | 3.4 | (2.0–4.0) | 1.9 | (1.0–3.8) | 0.082 |
| V20 Gy to heart (%); Md (IQR) | 4.6 | (1.5–5.3) | 1.4 | (0–4.5) | 0.052 |
| Dmean LV (Gy); Md (IQR) | 4.6 | (3.0–5.6) | 2.7 | (1.1–5.9) | 0.148 |
| V20 Gy to LV (%), Md (IQR) | 6.8 | (1.9–8.0) | 1.8 | (0–8.4) | 0.150 |
| Dmean RV (Gy), Md (IQR) | 2.4 | (1.7–3.0) | 1.5 | (1.0–2.9) | 0.073 |
| Dmean LAD (Gy), Md (IQR) | 23.7 | (10.5–28.9) | 9.4 | (1.4–24.8) | 0.012 |
| V20 GY to LAD (%), Md (IQR) | 50.3 | (14.7–71.9) | 12.8 | (0–55.0) | 0.015 |
| GLS at different time points | |||||
| GLS baseline (%), Md (IQR) | ─20.0 | (─23.3-─17.0) | ─17.0 | (─19.0-─15.0) | 0.036 |
| GLS after RT (%), Md (IQR) | ─16.5 | (─19.3-─14.8) | ─17.0 | (─20.0-─15.0) | 0.704 |
| GLS at 3 years (%), Md (IQR) | ─14.0 | (─16.3-─11.0) | ─18.0 | (─20.0-─16.0) | < 0.001 |
| ST2 levels | |||||
| ST2 baseline (ng/ml), Md (IQR) | 17.8 | (12.3–22.5) | 17.8 | (12.3–22.0) | 0.803 |
| ST2 after RT (ng/ml), Md (IQR) | 18.4 | (15.6–22.6) | 17.7 | (12.6–23.5) | 0.561 |
| ST2 at 3 years (ng/ml), Md (IQR) | 19.9 | (16.0–25.1) | 18.0 | (15.5–22.4) | 0.383 |
GLS, global longitudinal strain; RT, radiotherapy; Md, median; IQR, interquartile range; BMI, body mass index; BC, breast cancer; AI, aromatase inhibitor; ACE, angiotensin converting enzyme inhibitor; ARB, angiotensin II receptor blocker; ASA, low dose acetylsalicylic acid; CAD, coronary artery disease; Diabetes, use of diabetes medication; Dmean; mean dose to the structure; V20, the percentage of volume of the structure receiving 20 Gy; LV, left ventricle; RV, right ventricle; LAD, left anterior descending coronary artery; p, p-value from the Mann-Whitney U test.
Statistical significance is shown in bold (p < 0.05).