Table 3.
Associations between percentage of heart volume receiving ≥5 to ≥25 Gray (V5 to V25) and heart failure risk in patients treated with anthracyclines and without trastuzumab
| Percentage of heart volume receiving 5–25 Gy (V5 to V25) | Cases (n = 29)a | Controls (n = 51)a | RR | Floating 95% CI | P‐value |
|---|---|---|---|---|---|
| V5 | |||||
| Median value [IQR] | 35.4% [11.2–67.1] | 3.0% [0–43.7] | |||
| 0–9% |
6 (20.7) |
28 (54.9) |
1.0b | 0.31–3.3 | |
| 10–19% |
4 (13.8) |
5 (9.8) |
1.1 | 0.29–4.3 | 0.90 |
| ≥20% |
19 (65.5) |
18 (35.3) |
2.7 | 1.2–6.2 | 0.11 |
| V10 | |||||
| Median value [IQR] | 30.7% [7.0–59.2] | 1.7% [0–38.5] | |||
| 0–9% | 10 (34.5) | 32 (62.8) | 1.0b | 0.40–2.5 | |
| 10–19% | 3 (10.3) | 4 (7.8) | 0.7 | 0.15–3.6 | 0.74 |
| ≥20% | 16 (55.2) | 15 (29.4) | 2.8 | 1.1–7.0 | 0.06 |
| V20 | |||||
| Median value [IQR] | 15.0% [3.2–26.0] | 1.1% [0–13.8] | |||
| 0–9% |
13 (44.8) |
36 (70.6) |
1.0b | 0.43–2.3 | |
| 10–19% |
4 (13.8) |
10 (19.6) |
1.4 | 0.36–5.3 | 0.65 |
| ≥20% |
12 (41.4) |
5 (9.8) |
5.7 | 1.7–19.4 | 0.01 |
| V25 | |||||
| Median value [IQR] | 11.2% [2.0–20.1] | 1.0% [0.1–8.9] | |||
| 0–9% |
14 (48.3) |
43 (84.3) |
1.0b | 0.43–2.3 | |
| 10–19% |
7 (24.1) |
5 (9.8) |
4.1 | 1.0–15.9 | 0.05 |
| ≥20% |
8 (27.6) |
3 (5.9) |
7.8 | 1.8–34.6 | 0.01 |
CI, confidence interval; IQR, interquartile range; RR, rate ratio; V5‐V25, dose–volume parameters.
Dose–volume estimation was not possible for the three patients treated with anthracyclines and without trastuzumab, all cases, who had been treated with a combination of orthovoltage and electron/megavoltage radiotherapy, and for the four patients treated with anthracyclines without trastuzumab, all controls, for whom the radiotherapy charts were unavailable.
Reference category.