Table 2.
Patient and Tumor Characteristics for T1a,bN0M0 Breast Cancer by Subtype, Iowa, 2010–2012
| Subtypea | P valueb | |||
|---|---|---|---|---|
|
| ||||
| HER2+ | HR+ | TNBC | ||
|
| ||||
| N | 128 | 1,233 | 93 | |
|
| ||||
| Median age at diagnosis | 59 | 66 | 64 | P<0.0001 |
| Age at diagnosis | ||||
| ≤39 | 5 (3.9%) | 7 (0.6%) | 3 (3.2%) | |
| 40–49 | 22 (17.2%) | 100 (8.1%) | 7 (7.5%) | |
| ≥50 | 101 (78.9%) | 1,126 (91.3%) | 83 (89.3%) | |
|
| ||||
| AJCC Stage at diagnosis | P=0.021 | |||
| T1aN0M0 | 52 (40.6%) | 359 (29.1%) | 25 (26.9%) | |
| T1bN0M0 | 76 (59.4%) | 874 (70.9%) | 68 (73.1%) | |
|
| ||||
| Tumor grade | P<0.0001 | |||
| Well differentiated | 17 (13.3%) | 629 (51.0%) | 4 (4.3%) | |
| Moderately differentiated | 66 (51.6%) | 481 (39.0%) | 31 (33.3%) | |
| Poorly differentiated | 42 (32.8%) | 108 (8.8%) | 58 (62.4%) | |
| Unknown | 3 (2.3%) | 15 (1.2%) | 0 | |
|
| ||||
| Histology | P=0.110 | |||
| Ductal | 118 (92.2%) | 1,067 (86.5%) | 86 (92.5%) | |
| Lobular | 4 (3.1%) | 93 (7.6%) | 2 (2.1%) | |
| Other | 6 (4.7%) | 73 (5.9%) | 5 (5.4%) | |
|
| ||||
| Race | P=0.571 | |||
| Caucasian | 124 (96.9%) | 1,210 (98.1%) | 93 (100.0%) | |
| Non-Caucasian | 3 (2.3%) | 18 (1.5%) | 0 | |
| Unknown | 1 (0.8%) | 5 (0.4%) | 0 | |
Abbreviations: HER2 = human epidermal growth factor receptor 2; HR=estrogen or progesterone hormone receptor; TNBC=triple negative breast cancer; AJCC = American Joint Committee on Cancer
a
Subtype data missing for T1aN0M0 (n=83) and T1bN0M0 (n=150).
b
Calculated using χ2 test, “unknown” categories not included.