Table 8.
Multivariate Cox Proportional Hazard Modelling of Clinical and Treatment Factors
| Variable | Disease-Free Survival | Overall Survival | ||||
|---|---|---|---|---|---|---|
| HR | 95% CI | P valuea | HR | 95% CI | P valuea | |
| Radiation technique | ||||||
| 3D CRT | 1 | 1 | ||||
| IMRT | 1.025 | 0.524 to 2.004 | 0.943 | 0.670 | 0.287 to 1.563 | 0.354 |
| Fractionation | ||||||
| Conventional | 1 | 1 | ||||
| Hypofractionated | 1.090 | 0.527 to 2.257 | 0.816 | 1.298 | 0.544 to 3.096 | 0.556 |
| Surgery | ||||||
| Conserved | 1 | 1 | ||||
| Mastectomy | 2.099 | 0.927 to 4.753 | 0.076 | 2.073 | 0.781 to 5.499 | 0.143 |
| Tumor size | ||||||
| T1 | 1 | 1 | ||||
| T2 | 0.984 | 0.440 to 2.202 | 0.989 | 1.058 | 0.427 to 2.622 | 0.904 |
| T3, T4 | 2.988 | 1.166 to 7.655 | 0.023 | 3.384 | 1.217 to 9.407 | 0.019 |
| Nodal status | ||||||
| N0 | 1 | 1 | ||||
| N1 | 1.558 | 0.601 to 4.038 | 0.362 | 0.985 | 0.338 to 2.870 | 0.978 |
| N2/N3 | 5.529 | 2.187 to 13.977 | 0.0003 | 1.977 | 0.670 to 5.834 | 0.217 |
| Chemotherapy | ||||||
| No | 1 | 1 | ||||
| Yes | 0.638 | 0.234 to 1.737 | 0.379 | 0.689 | 0.249 to 1.907 | 0.473 |
Notes: aP values were adjusted using a multivariate Cox proportional hazard regression model including all factors listed; bold type indicates significance.
Abbreviations: CI, confidence interval; HR, Hazard ratio; IMRT, intensity modulated radiotherapy; 3D CRT, 3-dimensional conformal radiotherapy.