Table 1.
Baseline characteristics.
| Hypofractionated radiotherapy (HFRT) (n = 903) | Conventionally fractionated radiotherapy (CFRT) (n = 107) | p-value | |
|---|---|---|---|
| Age | <0.05 | ||
| Median (range)—year | 47 (26, 86) | 42 (24, 78) | |
| Menopausal status—no. (%) | 0.01 | ||
| Premenopausal | 656 (72.6%) | 90 (84.1%) | |
| postmenopausal | 247 (27.4%) | 17 (15.9%) | |
| Tumor laterality—no. (%) | 0.38 | ||
| left | 444 (49.2%) | 60 (56.1%) | |
| right | 458 (50.7%) | 47 (43.9%) | |
| bilateral | 1 (0.1%) | 0 (0%) | |
| Modified T stage—no. (%) | 0.08 | ||
| T1 | 440 (48.7%) | 32 (29.9%) | |
| T2 | 390 (43.2%) | 49 (45.8%) | |
| T3 | 49 (5.4%) | 17 (15.9%) | |
| T4 | 24 (2.7%) | 9 (8.4%) | |
| Modified N stage—no. (%) | <0.05 | ||
| N0 | 364 (40.3%) | 13 (12.1%) | |
| N1 | 328 (36.3%) | 43 (40.2%) | |
| N2 | 135 (15.0%) | 22 (20.6%) | |
| N3 | 76 (8.4%) | 29 (27.1%) | |
| Modified stage—no. (%) | <0.05 | ||
| I (IA/IB) | 246 (27.2%) | 6 (5.6%) | |
| II (IIA/IIB) | 419 (46.4%) | 41 (38.3%) | |
| III (IIIA/IIIB/IIIC) | 238 (26.4%) | 60 (56.1%) | |
| ER positive—no. (%) | 682 (75.5%) | 72 (67.3%) | 0.08 |
| PR positive—no. (%) | 604 (66.9%) | 70 (65.4%) | 0.84 |
| HER2 positive—no. (%) | 250 (27.7%) | 31 (29.0%) | 0.87 |
| Subgroups—no. (%) | 0.28 | ||
| HR+/HER2− | 539 (59.7%) | 56 (52.3%) | |
| HER2+/HR− | 101 (11.2%) | 11 (10.3%) | |
| HER2+/HR+ | 149 (16.5%) | 20 (18.7%) | |
| HR−/HER2− | 114 (12.6%) | 20 (18.7%) | |
| Breast surgery procedure—no. (%) | <0.05 | ||
| Breast conserving therapy (BCT) | 470 (52.0) | 7 (6.5%) | |
| Mastectomy | 433 (48.0%) | 100 (93.5%) | |
| Axillary nodes procedure—no. (%) | <0.05 | ||
| Sentinel lymph node biopsy only | 353 (39.1%) | 8 (7.5%) | |
| Axillary lymph node dissection (ALND) | 550 (60.9%) | 99 (92.5%) | |
| Close or positive margin—no. (%) | 47 (5.2%) | 5 (4.7%) | 1.00 |
| Chemotherapy—no. (%) | 812 (89.9%) | 104 (97.2%) | <0.05 |
| Chemotherapy strategy— no. (%) | <0.05 | ||
| None | 91 (10.1%) | 3 (2.8%) | |
| Neoadjuvant | 124 (13.7%) | 34 (31.8%) | |
| Adjuvant | 665 (73.6%) | 66 (61.7%) | |
| Neoadjuvant + adjuvant | 23 (2.6%) | 4 (3.7%) | |
| Anti-HER2 target therapy—no. (%) | 236 (26.1%) | 30 (28.0%) | 0.58 |
| Endocrine therapy—no. (%) | 688 (76.2%) | 76 (71.0%) | 0.29 |
| Radiotherapy technique—no. (%) | <0.05 | ||
| VMAT | 130 (14.4%) | 34 (31.8%) | |
| 2-field | 348 (38.5%) | 5 (4.7%) | |
| 3DCRT | 425 (47.1%) | 68 (63.5%) | |
| RT fields—no. (%) | <0.05 | ||
| Breast alone | 350 (38.8%) | 5 (4.7%) | |
| Breast/chest wall + SCF | 411 (45.5%) | 56 (52.3%) | |
| Breast/chest wall + SCF + IMN | 137 (15.2%) | 44 (41.1%) | |
| Breast/chest wall + SCF + Axillary | 5 (0.5%) | 2 (1.9%) | |
| RT Dose and fractions—no. (%) | <0.05 | ||
| 40.5 Gy/15 fx | 903 (100%) | 0 (0%) | |
| 50 Gy/25 fx | 0 (0%) | 95 (88.8%) | |
| 60–62.5 Gy/25–26 fx | 0 (0%) | 12 (11.2%) | |
| Electron boost | <0.05 | ||
| 10 Gy/5 frs | 437 (48.4%) | 8 (7.5%) | |
| 16 Gy/8 frs | 51 (5.6%) | 5 (4.7%) | |
| Use of RPM—no. (%) | 13 (1.4%) | 8 (7.5%) | <0.05 |
T, Tumor; N, Nodal; ER, estrogen receptor; PR, progesterone receptor; HR, hormone receptor; HER2, human epidermal growth factor receptor 2; 2D-fields, 2-field tangential opposing technique; 3DCRT, three-dimensional conformal technique; VMAT, volume modulated arc therapy; SCF, supraclavicular lymph nodes; IMN, internal mammary nodal; RT, radiotherapy; fx, fractions; RPM, real-time position management.