Table 1.
Baseline characteristics and 5-year LRR rates of 4841 pT1–2 N0 breast cancer patients after mastectomy
| Variables | n (%) | 5-year LRR (%) | p |
|---|---|---|---|
| Treatment era | |||
| 1999–2007 | 1915 (39.6) | 5.5 | < 0.001 |
| 2008–2014 | 2926 (60.4) | 2.8 | |
| Age (years) | |||
| Median | 51.1 ± 10.5 | ||
| ≤ 40 | 723 (14.9) | 7.5 | < 0.001 |
| > 40 | 4118 (85.1) | 3.3 | |
| Tumor quadrant | |||
| Inner | 1255 (25.9) | 5.3 | < 0.001 |
| Non-inner | 3486 (72.0) | 3.0 | |
| Unknown | 100 (2.1) | 18.9 | |
| pT stage | |||
| T2 | 1954 (40.4) | 5.3 | 0.003 |
| T1 | 2887 (59.6) | 3.0 | |
| Molecular subtype | |||
| Luminal | 3150 (65.0) | 2.8 | < 0.001 |
| Her2 overexpression | 501 (10.3) | 5.0 | |
| Triple-negative | 1076 (22.2) | 6.5 | |
| Unknown | 114 (2.4) | 5.3 | |
| LVI | |||
| Yes | 184 (3.8) | 8.1 | 0.011 |
| No | 4631 (95.7) | 4.0 | |
| Unknown | 26 (0.5) | 11.6 | |
| Tumor grade | |||
| I and II | 2803 (57.9) | 3.3 | 0.012 |
| III | 1137 (23.5) | 5.1 | |
| Unknown | 901 (18.6) | 4.6 | |
| Histology | |||
| IDC | 4399 (90.9) | 4.0 | 0.356 |
| ILC | 141 (2.9) | 1.9 | |
| IMPC | 26 (0.5) | 0.0 | |
| MBC | 4 (0.1) | 0.0 | |
| Medullary carcinoma | 56 (1.2) | 6.0 | |
| Other | 215 (4.4) | 2.4 | |
| Adjuvant chemotherapy | |||
| Yes | 3236 (66.8) | 2.1 | < 0.001 |
| No | 1605 (33.2) | 4.8 | |
| Endocrine therapy | |||
| Yes | 3113 (64.3) | 2.8 | < 0.001 |
| No | 1682 (34.7) | 6.1 | |
| Unknown | 46 (1.0) | 0.0 | |
| Median time (months) | 44.7 ± 21.6 | ||
| Anti-Her2 target therapy | |||
| Yes | 233 (4.8) | 3.4 | 0.372 |
| No | 4580 (94.6) | 4.0 | |
| Unknown | 28 (0.6) | 0.0 | |
ER Estrogen receptor, Her2 Human epidermal growth factor receptor 2, IDC Invasive ductal carcinoma, ILC Invasive lobular carcinoma, IMPC Invasive micropapillary carcinoma, LRR Locoregional recurrence, LVI Lymphovascular invasion, MBC Metaplastic breast carcinoma, PR Progesterone receptor