Table 3.
Correlation analyses for multiple parameters in accordance to CTCAE score, maximum L* value and maximum a* value. Values indicate p-values for the slope deviances of respective linear regressions, a + or − (in brackets) indicates whether the regression was positive or negative. Values in bold indicate statistically significant differences (p < 0.05).
| Parameter | CTCAE | L* Max. | a* Max. |
|---|---|---|---|
| Age [a] | 0.1289 (−) | 0.0825 (+) | 0.5491 (−) |
| BMI [kg/m2] | 0.2282 (+) | 0.9428 (−) | 0.1212 (+) |
| Breast volume [mL] | 0.0047 (+) | 0.9379 (+) | 0.0509 (+) |
| Boost (y/n) | 0.0635 (+) | 0.5084 (−) | 0.9629 (+) |
| Boost vol. [mL] | 0.6119 (+) | 0.6456 (−) | 0.4453 (+) |
| Mean Dose to PTV [%] | 0.4435 (−) | 0.9059 (−) | 0.9889 (+) |
| rel. D2% | 0.5635 (−) | 0.1062 (−) | 0.1147 (+) |
| rel. D50% | 0.5532 (−) | 0.1087 (−) | 0.1210 (+) |
| rel. D98% | 0.5595 (−) | 0.1011 (−) | 0.1178 (+) |
| V≥107% [mL] | 0.8424 (+) | 0.5715 (−) | 0.9127 (+) |
| HIRTOG | 0.8209 (+) | 0.8924 (+) | 0.3468 (+) |
| HI(D2%–D98%)/D50% | 0.7125 (+) | 0.7217 (+) | 0.7711 (+) |
| L* baseline | 0.2848 (−) | <0.0001 (+) | 0.0155 (−) |
| a* baseline | 0.2892 (+) | <0.0001 (−) | 0.0006 (+) |
| b* baseline | 0.3702 (−) | 0.0002 (−) | 0.5846 (+) |
| CTCAE | <0.0001 (−) | <0.0001 (+) | |
| L* max. | <0.0001 (−) | <0.0001 (−) | |
| a* max. | <0.0001 (+) | <0.0001 (−) | |
| b* max. | 0.5229 (−) | 0.1258 (−) | 0.4628 (+) |
| Pain (RISRAS) | <0.0001 (+) | 0.0115 (−) | 0.002 (+) |
| Burning (RISRAS) | 0.0003 (+) | 0.025 (−) | 0.0856 (+) |
| Itching (RISRAS) | 0.1517 (+) | 0.8369 (−) | 0.7335 (−) |
| Activities (RISRAS) | <0.0001 (+) | 0.0011 (−) | 0.0409 (+) |
Abbreviations: BMI = Body Mass Index; IMRT = Intensity-modulated Radiotherapy (sliding-window); VMAT = Volumetric (partial-) arc therapy; PTV = Planning Target Volume; V≥107% = Volume receiving ≥ 107% of prescribed dose; HIRTOG = Homogeneity index (Radiation Oncology Therapy Group); HI(D2%–D98%)/D50% = Homogeneity index [(D2%–D98%)/D50%]; CTCAE = Common Terminology Criteria for Adverse Effects; RISRAS = Radiation Induced Skin Reaction Assessment Scale; rel. D2%, rel. D50%, rel. D98% = Dose received by 2%, 50%, or 98% of the target volume relative to the prescribed dose, respectively.