Table 1.
Tumor characteristics at diagnosis according to breast cancer phenotypes in the Nurses' Health Studies
| Luminal A | Luminal B | HER2-enriched | Basal-like | Unclassified | |
|---|---|---|---|---|---|
|
|
|||||
| N (%) | 2063 (54.8) | 1008 (26.8) | 209 (5.6) | 378 (10.0) | 110 (2.9) |
| Mean age at diagnosis, years | 56.9 | 58.3 | 57.7 | 54.1 | 54.4 |
| Median age at diagnosis, years | 56.9 | 58.2 | 57.2 | 53.3 | 54.8 |
| Tumor size, N (%)a,c | |||||
| 0.1 to 1.0 cm | 535 (26.9) | 223 (23.8) | 34 (17.0) | 47 (13.1) | 20 (19.8) |
| 1.1 to less than 2.0 cm | 816 (41.1) | 402 (41.1) | 56 (28.0) | 120 (33.4) | 36 (35.6) |
| 2.0 to less than 4 cm | 449 (22.6) | 269 (27.5) | 85 (42.5) | 165 (46.0) | 30 (29.7) |
| >4+ cm | 186 (9.4) | 74 (7.6) | 25 (12.5) | 27 (7.5) | 15 (14.9) |
| Missing | 77 | 30 | 9 | 19 | 9 |
| Nodal involvement, N (%)a,c | |||||
| No nodes | 1276 (65.9) | 601 (64.3) | 103 (51.8) | 218 (61.4) | 59 (59.6) |
| 1–3 nodes | 398 (20.6) | 204 (21.8) | 48 (24.1) | 90 (25.4) | 14 (14.1) |
| 4–9 nodes | 153 (7.9) | 84 (9.0) | 25 (12.6) | 32 (9.0) | 11 (11.1) |
| 10+ nodes/metastatic | 110 (5.7) | 46 (4.9) | 23 (11.6) | 15 (4.2) | 15 (15.2) |
| Missing | 126 | 73 | 10 | 23 | 11 |
| Stage, N (%)a,c | |||||
| Stage I/II | 1572 (83.9) | 768 (83.9) | 137 (71.4) | 289 (85.0) | 68 (72.3) |
| Stage III/IV | 302 (16.1) | 147 (16.1) | 55 (28.7) | 51 (15.0) | 26 (27.7) |
| Missing | 189 | 93 | 17 | 38 | 16 |
| Grade, N (%)b,c | |||||
| Well-differentiated | 580 (28.2) | 148 (14.8) | 4 (2.0) | 7 (1.9) | 17 (15.5) |
| Intermediate differentiated | 1328 (64.7) | 522 (52.4) | 96 (47.1) | 97 (25.8) | 43 (39.1) |
| Poorly differentiated | 146 (7.1) | 327 (32.8) | 104 (51.0) | 272 (72.3) | 50 (45.5) |
| Missing | 9 | 11 | 5 | 2 | 0 |
| Histologic type, N (%)a,c | |||||
| Invasive ductal | 1637 (79.9) | 863 (85.6) | 203 (97.1) | 351 (95.4) | 95 (88.8) |
| Invasive lobular | 291 (14.2) | 83 (8.3) | 2 (1.0) | 4 (1.1) | 7 (6.5) |
| Invasive ductal/lobular | 109 (5.3) | 42 (4.2) | 0 (0.0) | 2 (0.5) | 2 (1.9) |
| Invasive NOS | 13 (0.6) | 9 (0.9) | 2 (1.0) | 11 (3.0) | 3 (2.8) |
| Missing | 13 | 11 | 2 | 10 | 3 |
| Race, N (%) | |||||
| White | 1965 (95.3) | 950 (94.3) | 203 (97.1) | 349 (92.3) | 106 (96.4) |
| Black | 23 (1.1) | 7 (0.7) | 1 (0.5) | 13 (3.4) | 1 (0.9) |
| Other | 75 (3.6) | 51 (5.1) | 5 (2.4) | 16 (4.2) | 3 (2.7) |
Percentages calculated among non-missing only, may not sum to 100 due to rounding
a
From hospital pathology reports;
b
From centralized pathology review;
c
Proportions calculated among non-missing