Table 2.
Breast tumor characteristics among case subjects
| Tumor characteristics | Category | No. | % |
|---|---|---|---|
| Tumor classification* | Tis | 63 | 21.14 |
| T1 | 146 | 48.99 | |
| T2 | 44 | 14.77 | |
| T3 | 6 | 2.01 | |
| TX | 14 | 4.70 | |
| Missing | 25 | 8.39 | |
| Lymph nodes classification* | pN0 | 210 | 70.47 |
| pN1 | 48 | 16.11 | |
| pN2 | 8 | 2.68 | |
| pN3 | 3 | 1.01 | |
| pNX | 4 | 1.34 | |
| Missing | 25 | 8.39 | |
| Metastasis classification* | M0 | 270 | 90.60 |
| MX | 3 | 1.01 | |
| Missing | 25 | 8.39 | |
| Breast cancer stage* | 0 | 55 | 18.46 |
| I | 118 | 39.60 | |
| II | 63 | 21.14 | |
| III | 13 | 4.36 | |
| Cannot stage | 24 | 8.05 | |
| Missing | 25 | 8.39 | |
| Estrogen receptor assay | Positive | 217 | 72.82 |
| Negative | 43 | 14.43 | |
| Missing | 38 | 12.75 | |
| Progesterone receptor assay | Positive | 168 | 56.38 |
| Negative | 75 | 25.17 | |
| Missing | 55 | 18.46 | |
| Location | Ductal | 225 | 75.50 |
| Lobular | 25 | 8.39 | |
| Both | 16 | 5.37 | |
| Other | 2 | 0.67 | |
| Missing | 30 | 10.07 | |
| HER-2/NEU | Overexpression | 23 | 7.72 |
| Not overexpression | 150 | 50.34 | |
| Missing | 125 | 41.95 |
* Breast cancer staging in the Sister Study used a modification of Tumor, Node, Metastasis (TNM 7) (31).