Table 2.
Univariate and multivariable Cox analyses of disease-free survival (DFS).
| Univariate | multivariable | ||||
|---|---|---|---|---|---|
| n (%) | HR | p-value | HR | p-value | |
| RT fractionation | |||||
| CFRT | 861 (89.5%) | 1 | 1 | ||
| HFRT | 101 (10.5%) | 1.60 (0.82, 3.15) | 0.17 | 0.79 (0.38, 1.64) | 0.53 |
| Age | |||||
| 45 y | 494 (51.4%) | 1 | |||
| >45 y | 468 (48.6%) | 1.00 (0.98, 1.03) | 0.83 | ||
| Menopausal status | |||||
| Premenopausal | 711 (73.9%) | 1 | |||
| postmenopausal | 251 (26.1%) | 1.09 (0.63, 1.88) | 0.75 | ||
| Modified T stage | |||||
| T1–2 | 868 (90.2%) | 1 | 1 | ||
| T3–4 | 94 (9.8%) | 4.06 (2.36, 6.99) | <0.05 | 2.50 (1.38, 4.54) | <0.05 |
| Modified N stage | |||||
| N0 | 360 (37.4%) | 1 | 1 | ||
| N1 | 355 (36.9%) | 1.87 (0.90, 3.90) | 0.10 | 1.54 (0.65, 3.62) | 0.32 |
| N2 | 147 (15.3%) | 3.77 (1.75, 8.12) | <0.05 | 2.95 (1.21, 7.21) | <0.05 |
| N3 | 100 (10.4%) | 6.36 (3.00, 13.47) | <0.05 | 4.70 (1.91, 11.59) | <0.05 |
| Modified N stage | |||||
| N0–1 | 715 (74.3%) | 1 | |||
| N2–3 | 247 (25.7%) | 3.36 (2.07, 5.47) | <0.05 | ||
| Modified stage | |||||
| I | 245 (25.5%) | 1 | |||
| II | 433 (45.0%) | 3.58 (1.25, 10.29) | <0.05 | ||
| III | 284 (29.5%) | 8.33 (2.96, 23.40) | <0.05 | ||
| ER status | |||||
| Negative | 244 (25.4%) | 1 | |||
| Positive | 718 (74.6%) | 0.35 (0.22, 0.58) | <0.05 | ||
| PR status | |||||
| Negative | 318 (33.1%) | 1 | |||
| Positive | 644 (66.9%) | 0.43 (0.27, 0.70) | <0.05 | ||
| HER2 status | |||||
| Negative | 695 (72.2%) | 1 | |||
| Positive | 267 (27.8%) | 1.67 (1.02, 2.76) | <0.05 | ||
| Subtypes | |||||
| HR+/HER2− | 569 (59.1%) | 1 | 1 | ||
| HER2+/HR− | 108 (11.2%) | 3.58 (1.95, 6.57) | <0.05 | 2.66 (1.43, 4.94) | <0.05 |
| HER2+/HR+ | 159 (16.5%) | 1.07 (0.49, 2.35) | 0.87 | 0.95 (0.43, 2.10) | 0.90 |
| HR−/HER2− | 126 (13.1%) | 2.25 (1.16, 4.35) | <0.05 | 2.32 (1.18, 4.55) | <0.05 |
| Breast surgery procedure | |||||
| Breast conserving therapy | 507 (5.7%) | 1 | 1 | ||
| Mastectomy | 455 (47.3) | 0.38 (0.22, 0.66) | <0.05 | 0.86 (0.41, 1.78) | 0.68 |
| Margin | |||||
| Negative | 914 (95.0%) | 1 | |||
| Close or positive | 48 (5.0%) | 0.93 (0.29, 2.95) | 0.90 | ||
| Chemotherapy strategy | |||||
| None | 92 (9.6%) | 1 | |||
| Neoadjuvant | 180 (18.7%) | 0.85 (0.37, 2.07) | 0.71 | ||
| Adjuvant | 690 (71.7%) | 0.67 (0.34, 1.50) | 0.30 | ||
| Radiotherapy technique | |||||
| VAMT | 155 (16.1%) | 1 | |||
| 2-field | 336 (34.9%) | 0.15 (0.07, 0.32) | <0.05 | ||
| 3DCRT | 471 (49.0%) | 0.38 (0.22, 0.64) | <0.05 | ||
| Electron boost | |||||
| None | 484 (50.3%) | 1 | |||
| Yes | 478 (49.7%) | 0.37 (0.22,0.64) | <0.05 | ||
| RT fields | |||||
| Tangential breast only | 338 (35.1%) | 1 | |||
| Breast/chest wall + SCF | 453 (47.1%) | 2.27 (1.07, 4.83) | <0.05 | ||
| Breast/chest wall + SCF + IMN | 171 (17.8%) | 6.96 (3.29, 14.69) | <0.05 | ||
RT, radiotherapy; HFRT, hypofractionated radiotherapy; CFRT, conventionally fractionated radiotherapy; T, Tumor; N, Nodal; ER, estrogen receptor; PR, progesterone receptor; HR, hormone receptor; HER2, human epidermal growth factor receptor 2; 2-field, 2-field tangential opposing technique; 3DCRT, three-dimensional conformal technique; VAMT, volume modulated arc therapy; SCF, supraclavicular lymph nodes; IMN, internal mammary nodal.