Table 1. Baseline characteristics and treatment patterns for all patients.
| IMPC (n = 188) | IDC (n = 1289) | ||||
| Characteristics | n | % | n | % | P value |
| Age, year (Mean±SD) | 52.7±11.3 | 51.7±10.4 | 0.196 | ||
| Menopausal status | 0.480 | ||||
| Premenopausal | 81 | 43.1 | 582 | 46.0 | |
| Postmenopausal | 107 | 56.9 | 682 | 54.0 | |
| Unknown | 25 | ||||
| Tumor size, cm | 0.002 | ||||
| T≤2 | 65 | 34.8 | 609 | 48.3 | |
| 2<T≤5 | 104 | 55.6 | 567 | 45.0 | |
| T>5 | 18 | 9.6 | 84 | 6.7 | |
| Unknown | 1 | 29 | |||
| Node status | <0.001 | ||||
| 0 | 50 | 26.6 | 702 | 55.3 | |
| 1–3 | 51 | 27.1 | 310 | 24.4 | |
| 4–9 | 48 | 25.5 | 158 | 12.5 | |
| ≥10 | 39 | 20.7 | 99 | 7.8 | |
| Unknown | 20 | ||||
| TNM stage | <0.001 | ||||
| I | 27 | 14.4 | 396 | 31.4 | |
| II | 64 | 34.2 | 593 | 47.0 | |
| III | 96 | 51.3 | 274 | 21.7 | |
| Unknown | 1 | 26 | |||
| ER status | <0.001 | ||||
| Positive | 160 | 85.1 | 908 | 72.5 | |
| Negative | 28 | 14.9 | 345 | 27.5 | |
| Unknown | 36 | ||||
| PR status | <0.001 | ||||
| Positive | 147 | 78.2 | 864 | 69.0 | |
| Negative | 41 | 21.8 | 389 | 31.0 | |
| Unknown | 36 | ||||
| HER2 status | 0.122 | ||||
| Positive | 55 | 29.9 | 307 | 24.5 | |
| Negative | 129 | 70.1 | 946 | 75.5 | |
| Unknown | 4 | 36 | |||
| Lymphovascular invasion | <0.001 | ||||
| Yes | 135 | 75.4 | 405 | 36.5 | |
| No | 44 | 24.6 | 706 | 63.5 | |
| Unknown | 9 | 178 | |||
| Subtype | <0.001 | ||||
| Luminal | 163 | 88.6 | 972 | 77.6 | |
| Non-luminal | 21 | 11.4 | 281 | 22.4 | |
| Unknown | 4 | 36 | |||
| Surgery | <0.001 | ||||
| Mastectomy | 179 | 95.2 | 1088 | 84.4 | |
| BCS | 9 | 4.8 | 201 | 15.6 | |
| Neoadjuvant chemotherapy | 0.026 | ||||
| Yes | 56 | 29.8 | 287 | 22.3 | |
| No | 132 | 70.2 | 1002 | 77.7 | |
| Adjuvant chemotherapy | 0.656 | ||||
| Yes | 176 | 93.6 | 1162 | 92.4 | |
| No | 12 | 6.4 | 96 | 7.6 | |
| Unknown | 31 | ||||
| Adjuvant radiotherapy | 0.005 | ||||
| Yes | 103 | 57.5 | 572 | 46.3 | |
| No | 76 | 42.5 | 663 | 53.7 | |
| Unknown | 9 | 50 | |||
| Adjuvant endocrine therapy | 0.023 | ||||
| Yes | 154 | 87.5 | 1016 | 80.4 | |
| No | 22 | 12.5 | 248 | 19.6 | |
| Unknown | 12 | 25 | |||
Abbreviations: IMPC, invasive micropapillary carcinoma; IDC, invasive ductal carcinoma; TNM, tumor, node, metastasis; ER, estrogen receptor; PR, progesterone receptor; HER-2, human epidermal growth factor receptor 2; BCS, breast-conserving surgery;
P-value is calculated by two-sided χ2 test;
Bold values denote P<0.05.