Table 1.
Patient characteristics for entire study population.
| Total patients | N = 1297 |
|---|---|
| Median age at diagnosis (years, range) | 37 (17–40) |
| N (%) | |
| Race* | |
| American Indian or Alaskan native | 6 (0.5) |
| Asian | 88 (6.8) |
| Black, Haitian or African American | 48 (3.7) |
| White | 1101 (84.9) |
| Other/unknown | 38 (2.9) |
| Multiracial | 16 (1.2) |
| First-degree family history breast or ovarian cancer** | |
| Yes | 176 (15.8) |
| No | 936 (84.0) |
| Unsure | 2 (0.2) |
| Missing | 183 |
| Bilateral | |
| Yes | 21 (1.6) |
| No | 1276 (98.4) |
| Stage | |
| 0 | 98 (7.6) |
| I | 413 (31.8) |
| II | 525 (40.5) |
| III | 197 (15.2) |
| IV | 64 (4.9) |
| Tumour grade | |
| Grades 1 and 2 | 534 (41.2) |
| Grade 3 | 752 (58.0) |
| Missing | 11 (0.9) |
| Oestrogen receptor (ER) | |
| Positive | 945 (72.9) |
| Negative | 351 (27.1) |
| Missing | 1 (0.1) |
| Progesterone receptor (PR) | |
| Positive | 848 (65.4) |
| Negative | 441 (34.0) |
| Missing | 8 (0.6) |
| HER2 (any ER status) | |
| Positive | 360 (27.8) |
| Negative | 880 (67.9) |
| Missing/not performed*** | 57 (4.4) |
| Subtype | |
| Luminal A-like (ER and/or PR + , HER2−, grade 1 or 2) | 395 (30.5) |
| Luminal B-like (ER and/or PR + , HER2−, grade 3) | 269 (20.7) |
| Luminal B/HER2 (ER and/or PR + , HER2 + ) | 255 (19.7) |
| HER2-enriched (ER−, PR−, HER2 + ) | 105 (8.1) |
| Triple-negative | 210 (16.2) |
| Missing/unknown subtype | 63 (4.9) |
| Genetic testing | |
| BRCA1 positive | 90 (6.9%) |
| BRCA2 positive | 54 (4.2%) |
| No mutation detected/VUS**** | 973 (75.0%) |
| No testing/Unknown | 180 (13.9%) |
*In total, 56 (4.3%) women self-identified as Hispanic or Latina.
**Mother or sister.
***Missing/unknown subtype includes cases of DCIS for which HER2 was not performed.
****VUS = variant of unknown significance, VUS = 4.2% (54/1297).