Table 1. Baseline Patient Demographics and Clinicopathologic Characteristics.
| Characteristic | Participants, %a | P valueb | ||
|---|---|---|---|---|
| Total (N = 1 136 016) | ERBB2-negative status (n = 392 246) | ERBB2-low status (n = 743 770) | ||
| Age, mean (SD), y | ||||
| <40 | 4.1 | 4.5 | 3.9 | <.001 |
| 40-49 | 13.9 | 14.2 | 13.8 | |
| 50-59 | 22.5 | 22.5 | 22.5 | |
| 60-69 | 28.8 | 28.4 | 28.9 | |
| 70-79 | 20.9 | 20.8 | 20.9 | |
| ≥80 | 9.8 | 9.6 | 10.0 | |
| Sex | ||||
| Female | 99.1 | 99.3 | 99.0 | <.001 |
| Male | 0.9 | 0.7 | 1.0 | |
| Race and ethnicity (9325c) | ||||
| Asian | 3.7 | 3.6 | 3.7 | <.001 |
| Hispanic | 5.6 | 6.3 | 5.2 | |
| Native American | 0.3 | 0.2 | 0.3 | |
| Non-Hispanic Black | 11.3 | 12.1 | 10.8 | |
| Non-Hispanic White | 78.6 | 77.1 | 79.5 | |
| Otherd | 0.5 | 0.6 | 0.5 | |
| Facility type (46 482c) | ||||
| Academic or research | 30.6 | 34.1 | 28.8 | <.001 |
| Community cancer program | 7.2 | 7.0 | 7.3 | |
| Comprehensive community cancer program | 41.4 | 39.0 | 42.6 | |
| Integrated network cancer program | 20.8 | 19.9 | 21.3 | |
| Charlson-Deyo Comorbidity Index score | ||||
| 0 | 82.0 | 82.2 | 81.9 | .003 |
| ≥1 | 18.0 | 17.8 | 18.1 | |
| Grade (48 845c) | ||||
| 1 | 26.1 | 24.4 | 27.0 | <.001 |
| 2 | 47.3 | 44.6 | 48.7 | |
| 3 | 26.6 | 31.0 | 24.3 | |
| Tumor histological characteristics | ||||
| Ductal | 77.7 | 75.5 | 78.9 | <.001 |
| Ductal and lobular | 5.3 | 5.2 | 5.3 | |
| Inflammatory | 0.2 | 0.2 | 0.1 | |
| Lobular | 11.7 | 12.4 | 11.3 | |
| Medullary | 0.1 | 0.2 | 0.1 | |
| Metaplastic | 0.5 | 1.0 | 0.3 | |
| Mucinous | 2.0 | 2.7 | 1.6 | |
| Paget disease | 0.1 | 0 | 0.1 | |
| Papillary | 0.3 | 0.3 | 0.3 | |
| Sarcoma | 0 | 0 | 0 | |
| Tubular | 0.6 | 0.5 | 0.6 | |
| Other | 1.6 | 2.0 | 1.4 | |
| T stage (96 912c) | ||||
| 0 | 0.3 | 0.3 | 0.3 | <.001 |
| 1 | 65.2 | 64.3 | 65.7 | |
| 2 | 27.3 | 27.8 | 27.1 | |
| 3 | 5.0 | 5.4 | 4.8 | |
| 4 | 2.1 | 2.2 | 2.1 | |
| N stage (134 296c) | ||||
| 0 | 72.2 | 72.8 | 71.9 | <.001 |
| 1 | 21.6 | 21.0 | 21.9 | |
| 2 | 4.0 | 3.9 | 4.1 | |
| 3 | 2.2 | 2.3 | 2.2 | |
| Stage | ||||
| I | 59.7 | 58.8 | 60.2 | <.001 |
| II | 27.2 | 27.5 | 27.1 | |
| III | 8.7 | 9.1 | 8.5 | |
| IV | 4.4 | 4.6 | 4.3 | |
| Bone metastasis at diagnosis (11 995c) | ||||
| No | 97.7 | 97.7 | 97.7 | .13 |
| Yes | 2.3 | 2.3 | 2.3 | |
| Brain metastasis at diagnosis (12 354c) | ||||
| No | 99.8 | 99.7 | 99.8 | <.001 |
| Yes | 0.2 | 0.3 | 0.2 | |
| Liver metastasis at diagnosis (12 270c) | ||||
| No | 99.3 | 99.3 | 99.4 | <.001 |
| Yes | 0.7 | 0.7 | 0.6 | |
| Lung metastasis at diagnosis (12 403c) | ||||
| No | 99.0 | 99.0 | 99.1 | .001 |
| Yes | 1.0 | 1.0 | 0.9 | |
| ERBB2/CEP17 ratio (793 991), mean (SD) | 1.3 (1.3) | 1.3 (2.2) | 1.3 (1.0) | .73 |
| ERBB2 copies (1 050 922c), mean (SD) | 2.7 (4.2) | 2.4 (4.7) | 2.8 (4.0) | <.001 |
| Receptor status (7217c) | ||||
| ER positive, PR positive | 75.8 | 69.2 | 79.3 | <.001 |
| ER positive, PR negative | 9.7 | 9.8 | 9.6 | |
| ER negative, PR positive | 0.8 | 1.1 | 0.7 | |
| ER negative, PR negative | 13.6 | 19.9 | 10.3 | |
| Percentage ER positive (860 499c), mean (SD) | 78.1 (35.2) | 70.8 (40.2) | 82.5 (31.1) | <.001 |
| Percentage PR positive (860 403c), mean (SD) | 53.9 (40.8) | 49.8 (42.2) | 56.4 (39.7) | <.001 |
| Percentage Ki67 positive (997 909c), mean (SD) | 24.6 (26.8) | 27.6 (30.1) | 22.8 (24.5) | <.001 |
| Oncotype Dx score (853 587c) | ||||
| High (≥26) | 12.5 | 12.4 | 12.6 | <.001 |
| Intermediate (11-25) | 62.5 | 61.6 | 62.9 | |
| Low (0-10) | 25.0 | 26.1 | 24.5 | |
| Receipt of chemotherapy (13 635c) | ||||
| Yes | 34.5 | 37.2 | 33.0 | <.001 |
| No | 65.5 | 62.8 | 67.0 | |
| Receipt of hormonal therapy (26 355c) | ||||
| Yes | 73.3 | 67.4 | 76.4 | <.001 |
| No | 26.7 | 32.6 | 23.6 | |
Abbreviations: CEP17, centromeric chromosome 17; ER, estrogen receptor; ERBB2, erb-b2 receptor tyrosine kinase 2; PR, progesterone receptor.
a
Percentages reflect the number of participants missing, as shown in the left column.
b
P values are listed for a χ2 test for categorical variables and a 2-sided t test for continuous variables.
c
Indicates number of patients for whom data were missing.
d
Other is a subcategory listed in the National Cancer Database (NCDB) and represents patients who were coded as such by the local cancer registry. No explicitly defined racial or ethnic subgroup categorized by the NCDB was collapsed into this category.