Table 2.
Comparison of average dose parameters for targets and OARs for left-sided breast cancers by treatment cohort
| Parameter | WBRT | WBRT FB vs. DIBH p-value* | B/CWRT + RNI | B/CWRT FB vs. DIBH p-value*** | All Patients | FB vs. DIBH p-value* |
|---|---|---|---|---|---|---|
| CTVb Volume (cc) | ||||||
| FB | 515.5 ± 356.9 | 0.577 | 489.2 ± 200.8 | 0.496 | 503.7 ± 290.2 | 0.349 |
| DIBH | 511.8 ± 354.6 | 491.3 ± 218.6 | 502.6 ± 294.0 | |||
| D95 for CTVb (%) | ||||||
| FB | 97.3 ± 1.4 | 0.286 | 92.2 ± 8.1 | 0.030 | 95.0 ± 5.9 | 0.013 |
| DIBH | 97.7 ± 1.3 | 96.2 ± 3.0 | 97.0 ± 2.3 | |||
| V80 IMC (%) | ||||||
| FB | N/A | N/A | 99.7 ± 0.9 | 1.000 | N/A | N/A |
| DIBH | N/A | 98.9 ± 3.3 | N/A | |||
| Dmean Heart (cGy) | ||||||
| FB | 166.1 ± 71.0 | 0.001** | 375.7 ± 186.0 | 0.004** | 260.5 ± 169.3 | <0.001** |
| DIBH | 110.8 ± 32.1 | 145.0 ± 37.7 | 126.2 ± 38.0 | |||
| V25 Heart (%) | ||||||
| FB | 0.8 ± 1.4 | 0.059 | 4.0 ± 3.4 | 0.014 | 2.2 ± 2.9 | 0.002** |
| DIBH | 0.1 ± 0.4 | 0.0 ± 0.1 | 0.1 ± 0.3 | |||
| Dmean LAD (cGy) | ||||||
| FB | 1004.6 ± 892.4 | 0.002** | 1802.8 ± 917.8 | 0.004** | 1363.8 ± 969.4 | <0.001** |
| DIBH | 420.0 ± 277.4 | 396.2 ± 81.5 | 409.3 ± 208.4 | |||
| V20 Left Lung (%) | ||||||
| FB | 10.5 ± 4.6 | 0.067 | 18.3 ± 5.1 | 0.250 | 14.0 ± 6.2 | 0.029 |
| DIBH | 8.5 ± 3.6 | 16.3 ± 2.8 | 12.0 ± 5.1 | |||
| Patients meeting | ||||||
| Dmean < 4Gy (fraction, %) | ||||||
| FB | 11/11 (100) | N/A | 5/9 (56) | 0.134 | 16/20 (80) | 0.134 |
| DIBH | 11/11 (100) | 9/9 (100) | 20/20 (100) |
Wilcoxon signed-rank test is used for comparison of all continuous variables, and McNemar's test is applied for discrete variables
Significant p-values after adjusting for multiple testing are indicated by a double asterisk (**)
Abbreviations: WBRT = whole breast RT ± boost cohort, B/CWRT + RNI = breast or chest wall + regional nodal RT cohort, FB = free-breathing, DIBH = deep inspiration breath hold, CTVb = CTV for breast or chest wall, IMC = internal mammary chain nodes, D95 = Dose to 95 % target volume,V80 = % volume of organ receiving 80 % of the prescription dose, V25 = % volume of organ receiving 25 Gy, Dmean = Mean dose, LAD = left anterior descending coronary artery, V20 = % volume of organ receiving 20 Gy, N/A = not applicable. Data shown are mean values with one standard deviation. *In this group, to achieve significance p-values must be < 0.0083 to account for multiple testing. ***In this group, to achieve significance p-values must be < 0.0071 to account for multiple testing. **Indicates significance when compared to the Bonferroni adjusted criterion