TABLE 1.
Comparisons of clinical characteristics between HER2‐zero and HER2‐low breast cancer (BC) by HR status.
| Characteristics a | Group | Overall BC (N = 11,911) | p value b | HR+ BC (N = 9902) | p value b | HR‐ BC (N = 2009) | p value b | |||
|---|---|---|---|---|---|---|---|---|---|---|
| HER2‐zero (N = 4265) | HER2‐low (N = 7646) | HER2‐zero (N = 3767) | HER2‐low (N = 6135) | HER2‐zero (N = 498) | HER2‐low (N = 1511) | |||||
| Age, years | ≤40 | 586 (13.7) | 1045 (13.7) | <0.001 | 503 (13.4) | 875 (14.3) | <0.001 | 83 (16.7) | 170 (11.3) | <0.001 |
| 41–50 | 1505 (35.3) | 2511 (32.9) | 1345 (35.7) | 2089 (34.1) | 160 (32.1) | 422 (28.0) | ||||
| 51–60 | 1234 (29.0) | 2516 (33.0) | 1058 (28.1) | 1925 (31.4) | 176 (35.3) | 591 (39.2) | ||||
| >60 | 937 (22.0) | 1563 (20.5) | 858 (22.8) | 1237 (20.2) | 79 (15.9) | 326 (21.6) | ||||
| HR | HR− | 498 (11.7) | 1511 (19.8) | <0.001 | — | — | — | — | ||
| HR+ | 3767 (88.3) | 6135 (80.2) | — | — | — | — | ||||
| pTNM | 0–I | 1019 (35.7) | 1943 (32.6) | 0.011 | 912 (36.1) | 1560 (32.5) | 0.007 | 107 (32.6) | 383 (33.2) | 0.148 |
| II | 1308 (45.8) | 2823 (47.4) | 1138 (45.1) | 2282 (47.5) | 170 (51.8) | 541 (46.9) | ||||
| III–IV | 526 (18.4) | 1194 (20.0) | 475 (18.8) | 965 (20.1) | 51 (15.5) | 229 (19.9) | ||||
| Grade | G1/G2 | 1548 (86.5) | 4458 (81.9) | <0.001 | 1372 (94.2) | 3869 (88.8) | <0.001 | 176 (52.9) | 589 (54.3) | 0.646 |
| G3 | 241 (13.5) | 986 (18.1) | 84 (5.8) | 490 (11.2) | 157 (47.1) | 496 (45.7) | ||||
| Ki‐67 | ≤14% | 1389 (32.6) | 1387 (18.1) | <0.001 | 1349 (35.8) | 1296 (21.1) | <0.001 | 40 (8.0) | 91 (6.0) | 0.115 |
| >14% | 2876 (67.4) | 6259 (81.9) | 2418 (64.2) | 4839 (78.9) | 458 (92.0) | 1420 (94.0) | ||||
| Endocrinotherapy | No | 2623 (66.3) | 4833 (71.9) | <0.001 | 2194 (62.2) | 3607 (66.0) | <0.001 | 429 (99.1) | 1226 (97.8) | 0.100 |
| Yes | 1336 (33.7) | 1888 (28.1) | 1332 (37.8) | 1861 (34.0) | 4 (0.9) | 27 (2.2) | ||||
| Chemotherapy | No | 691 (16.4) | 877 (11.7) | <0.001 | 638 (17.2) | 727 (12.1) | <0.001 | 53 (10.8) | 150 (10.1) | 0.690 |
| Yes | 3515 (83.6) | 6616 (88.3) | 3076 (82.8) | 5287 (87.9) | 439 (89.2) | 1329 (89.9) | ||||
| Radiotherapy | No | 3123 (77.4) | 5071 (72.1) | <0.001 | 2795 (78.2) | 4081 (72.1) | <0.001 | 328 (71.1) | 990 (72.4) | 0.599 |
| Yes | 912 (22.6) | 1958 (27.9) | 779 (21.8) | 1581 (27.9) | 133 (28.9) | 377 (27.6) | ||||
Note: G1/G2/G3, well/medium/poor differentiation.
a
Missing values in the index variable were not shown.
b
p value was calculated excludes missing values.
The bold values represent p <0.05.