Table 2. Univariate analysis for ipsilateral breast tumor recurrence.
| Variable | No. of patients | 7-yr IBTR rate (%) | p-value |
|---|---|---|---|
| Age (yr) | 0.389 | ||
| ≤ 40 | 107 | 6.4 | |
| > 40 | 179 | 4.9 | |
| Tumor size (cm) | 0.653 | ||
| ≤1 | 108 | 6.1 | |
| >1 | 158 | 5.5 | |
| Unknown | 20 | 0.0 | |
| Nuclear grade | 0.975 | ||
| 1 | 93 | 3.8 | |
| 2 | 103 | 4.0 | |
| 3 | 52 | 12.6 | |
| Unknown | 38 | 6.2 | |
| Margin involvement | 0.340 | ||
| Negative | 268 | 5.8 | |
| Positive | 18 | 0.0 | |
| Margin width (mm) | 0.534 | ||
| <2 | 159 | 5.4 | |
| ≥2 | 127 | 5.4 | |
| ER | 0.278 | ||
| Negative | 28 | 10.6 | |
| Positive | 220 | 5.3 | |
| Unknown | 38 | 3.0 | |
| PR | 0.299 | ||
| Negative | 43 | 4.3 | |
| Positive | 204 | 6.3 | |
| Unknown | 39 | 2.9 | |
| HER2* | 0.003 | ||
| Negative | 140 | 3.9 | |
| Positive | 56 | 13.6 | |
| Tamoxifen | 0.597 | ||
| No | 107 | 3.8 | |
| Yes | 176 | 6.5 | |
| Unknown | 3 | 0.0 | |
| RT | 0.008 | ||
| No | 54 | 13.1 | |
| Yes | 232 | 3.6 |
IBTR=ipsilateral breast tumor recurrence; ER=estrogen receptor; PR=progesterone receptor; HER2=human epidermal growth factor receptor 2; RT=radiation therapy.
*Ninety patients with unknown or equivocal HER2 status were excluded.