Table 2. Descriptive statistics of study variables .
| Categorical variables | Number | Percent |
| Primary site of tumor | ||
| Central | 104 | 18.3 |
| Upper inner quadrant | 217 | 38.1 |
| Lower inner quadrant | 83 | 14.6 |
| Upper outer quadrant | 112 | 19.7 |
| Lower outer quadrant | 53 | 9.3 |
| Metastases of tumor | ||
| Yes | 158 | 27.8 |
| No | 411 | 72.2 |
| Behavior of tumor | ||
| In situ | 208 | 36.6 |
| Malignant | 361 | 63.4 |
| Grade of tumor | ||
| I | 187 | 32.9 |
| II | 302 | 53.1 |
| III | 80 | 14.1 |
| Histology of tumor | ||
| Adenoid | 6 | 1.1 |
| Ductal carcinoma in situ | 17 | 3.0 |
| Epithelial | 3 | 0.5 |
| Invasive ductal carcinoma | 486 | 85.4 |
| Paget disease | 7 | 1.2 |
| Comedo | 6 | 1.1 |
| Invasive lobular carcinoma | 15 | 2.6 |
| Inflammatory | 2 | 0.4 |
| Mucinous | 5 | 0.9 |
| Papillary | 5 | 0.9 |
| Micropapillary | 5 | 0.9 |
| Medullary | 10 | 1.8 |
| Phyllodes | 2 | 0.4 |
| Stage of tumor | ||
| 1 | 18 | 3.2 |
| 2A | 123 | 21.6 |
| 2B | 102 | 17.9 |
| 3A | 151 | 26.5 |
| 3C | 26 | 4.6 |
| 4 | 149 | 26.2 |
| Surgery of tumor | ||
| No | 109 | 19.2 |
| Lumpectomy | 2 | 0.4 |
| Quadrantectomy | 7 | 1.2 |
| Modified radical mastectomy | 447 | 78.6 |
| Radical mastectomy | 4 | 0.7 |
| Radiation of tumor | ||
| Yes | 506 | 88.9 |
| No | 63 | 11.1 |
| Human epidermal growth factor receptor 2 (Her2) | ||
| Yes | 255 | 44.8 |
| No | 314 | 55.2 |
| Estrogen receptor | ||
| Yes | 261 | 45.9 |
| No | 308 | 54.1 |
| Progesterone receptor | ||
| Yes | 288 | 50.6 |
| No | 281 | 49.4 |
| Survival | ||
| Yes | 384 | 67.5 |
| No | 185 | 32.5 |
| Continuous variables | Mean | SD |
| Age | 48.6 | 10.6 |
| Tumor size | 4.0 | 1.9 |
| Number of positive regional nodes | 3.6 | 4.3 |
| Number of removed regional nodes | 8.4 | 5.7 |