Table 1. Patient and tumor characteristics.
| Variable | No-RT group (n = 54) No. (%) | RT group (n = 232) No. (%) | p-value |
|---|---|---|---|
| Age (yr) | 0.950 | ||
| ≤ 40 | 20 (37) | 87 (38) | |
| > 40 | 34 (63) | 145 (63) | |
| Tumor size (cm) | < 0.001 | ||
| ≤1 | 38 (70) | 70 (30) | |
| >1 | 16 (30) | 142 (61) | |
| Unknown | 0 | 20 (9) | |
| Nuclear grade | < 0.001 | ||
| 1 | 31 (57) | 62 (27) | |
| 2 | 14 (26) | 89 (38) | |
| 3 | 5 (9) | 47 (20) | |
| Unknown | 4 (7) | 34 (15) | |
| Margin involvement | 0.034 | ||
| Negative | 54 (100) | 214 (92) | |
| Positive | 0 | 18 (8) | |
| Margin width (mm) | < 0.001 | ||
| <2 | 13 (24) | 146 (63) | |
| ≥2 | 41 (76) | 86 (37) | |
| ER | 0.010 | ||
| Negative | 2 (4) | 26 (11) | |
| Positive | 50 (93) | 170 (73) | |
| Unknown | 2 (4) | 36 (16) | |
| PR | 0.001 | ||
| Negative | 2 (4) | 41 (18) | |
| Positive | 50 (93) | 154 (66) | |
| Unknown | 2 (4) | 37 (16) | |
| HER2 | 0.004 | ||
| Negative | 33 (61) | 107 (46) | |
| Equivocal | 4 (7) | 38 (16) | |
| Positive | 15 (28) | 41 (18) | |
| Unknown | 2 (4) | 46 (20) | |
| Tamoxifen | 0.167 | ||
| No | 15 (28) | 92 (40) | |
| Yes | 39 (72) | 137 (59) | |
| Unknown | 0 | 3 (1) |
RT=radiation therapy; ER=estrogen receptor; PR=progesterone receptor; HER2=human epidermal growth factor receptor 2.