Table 1. Patient demographic and clinical data.
| Characteristic | Entire cohort | Without PMRT (%) | With PMRT (%) | P |
|---|---|---|---|---|
| Age (y) | ||||
| <35 | 83 | 67 (10.8) | 16 (20.3) | 0.015 |
| ≥35 | 614 | 551 (89.2) | 63 (79.7) | |
| Menopausal status | ||||
| Premenopausal | 463 | 398 (64.4) | 66 (83.5) | 0.001 |
| Postmenopausal | 233 | 220 (35.6) | 13 (16.5) | |
| Tumor size | ||||
| pT1 | 218 | 205 (33.2) | 13 (16.5) | 0.003 |
| pT2 | 479 | 413 (66.8) | 66 (83.5) | |
| Positive lymph nodes (n) | ||||
| 1 | 334 | 317 (51.3) | 17 (21.5) | < 0.001 |
| 2 | 194 | 175 (28.3) | 19 (24.1) | |
| 3 | 169 | 126 (20.4) | 43 (54.4) | |
| Lymphatic invasion | ||||
| Negative | 670 | 598 (96.8) | 72 (91.1) | 0.015 |
| Positive | 27 | 20 (3.3) | 7 (8.9) | |
| Molecular subtype | ||||
| Luminal A | 364 | 334 (54.0) | 30 (38.0) | 0.014 |
| Luminal B | 144 | 118 (19.1) | 26 (32.9) | |
| Her2-enriched | 101 | 87 (14.1) | 14 (17.7) | |
| Triple negative | 88 | 79 (12.8) | 9 (11.4) | |
| LNR (%) | ||||
| ≤ 20 | 615 | 562 (90.9) | 53 (67.1) | < 0.001 |
| > 20 | 82 | 56 (9.1) | 26 (32.9) | |
| Chemotherapy | ||||
| No | 30 | 30 (4.9) | 0 (0) | 0.045 |
| Yes | 667 | 588 (95.1) | 79 (100) |
PMRT, postmastectomy radiotherapy; LNR, lymph node ratio.