Table 1.
Baseline characteristics. BMI = body mass index; SD = standard deviation; 3D-CRT = 3D-conformal radiotherapy; IMRT = intensity-modulated radiotherapy. Relevant comorbidities were defined as morbidities that may impair treatment conduct (e.g., unstable cardiac disease).
| Mean (SD) | Median | Range | ||
|---|---|---|---|---|
| Age (years) | 61.68 (9.98) | 61.5 | 33–85 | |
| BMI (kg/m2) | 27.29 (4.78) | 26.7 | 17.1–43.9 | |
| ECOG performance status | 0 | 0–2 | ||
| Tumor size (mm) | 15.46 (8.86) | 13 | 2–55 | |
| N (%) | ||||
| Comorbidity | Relevant | Not relevant | None | Unknown |
| Heart | 0 (0) | 36 (13.1) | 209 (76.3) | 29 (10.6) |
| Lung | 0 (0) | 14 (5.1) | 231 (84.3) | 29 (10.6) |
| Kidney | 0 (0) | 7 (2.5) | 238 (86.9) | 29 (10.6) |
| Axillary surgery | ||||
| Sentinel lymph node biopsy | 236 (86.1) | |||
| Axillary dissection | 37 (13.5) | |||
| No axillary staging | 1 (0.4) | |||
| (y)pT category | ||||
| T0 (after neoadjuvant treatment) | 6 (2.2) | |||
| T1a | 12 (4.4) | |||
| T1b | 73 (26.6) | |||
| T1c | 130 (47.4) | |||
| T2 | 52 (19.0) | |||
| T3 | 1 (0.4) | |||
| T4 | 0 (0) | |||
| pN category | ||||
| N0 | 255 (93.0) | |||
| N1mic | 4 (1.5) | |||
| N1 | 15 (5.5) | |||
| cM stage | ||||
| M0 | 266 (97.1) | |||
| M1 | 0 (0) | |||
| Unknown | 8 (2.9) | |||
| Laterality | ||||
| Right | 132 (48.2) | |||
| Left | 142 (51.8) | |||
| Histological type | ||||
| Invasive-ductal | 213 (77.8) | |||
| Invasive-lobular | 45 (16.4) | |||
| Medullary | 2 (0.7) | |||
| Other | 11 (4.0) | |||
| Unknown | 3 (1.1) | |||
| Estrogen receptor | ||||
| Negative | 37 (13.5) | |||
| Positive | 222 (81.0) | |||
| Unknown | 15 (5.5) | |||
| Progesterone receptor | ||||
| Negative | 50 (18.3) | |||
| Positive | 207 (75.5) | |||
| Unknown | 17 (6.2) | |||
| HER2-status | ||||
| 0 | 122 (44.5) | |||
| 1+ | 90 (32.9) | |||
| 2+ | 33 (12.0) | |||
| 3+ | 14 (5.1) | |||
| Unknown | 15 (5.5) | |||
| Chemotherapy-status | ||||
| None | 165 (60.2) | |||
| Neoadjuvant | 16 (5.8) | |||
| Adjuvant | 85 (31.1) | |||
| Unknown | 8 (2.9) | |||
| Endocrine therapy | ||||
| None | 35 (12.8) | |||
| Started at time of radiotherapy | 82 (29.9) | |||
| Planned | 137 (50) | |||
| Unknown | 20 (7.3) | |||
| Type of endocrine therapy | ||||
| Tamoxifen | 117 (42.7) | |||
| Aromatase inhibitors | 65 (23.7) | |||
| Unknown | 57 (20.8) | |||
| Not applicable | 35 (12.8) | |||
| Radiotherapy technique | ||||
| 3D-CRT | 120 (43.8) | |||
| IMRT | 150 (54.7) | |||
| Unknown | 4 (1.5) | |||
| Boost | ||||
| 6 MeV photons only | 137 (50) | |||
| 6-MeV photons and other photon energies | 128 (46.7) | |||
| Photons and electrons | 1 (0.4) | |||
| Others | 2 (0.7) | |||
| Unknown | 6 (2.2) | |||