Table 2.
Characteristics of the 2492 Asian breast cancer patients treated with breast-conserving therapy (1989–2012)
| Characteristic | Age ≤ 40 years (n = 447) | Age > 40 years (n = 2045) | P value | Strength of association |
|---|---|---|---|---|
| Age (years) | ||||
| Median (range) | 36 (22–40) | 51 (41–92) | ||
| Race [n (%)] | ||||
| Chinese | 342 (76.5) | 1673 (81.8) | ||
| Indian | 21 (4.7) | 94 (4.6) | ||
| Malay | 40 (8.9) | 184 (9.0) | ||
| Others | 44 (9.8) | 94 (4.6) | < 0.001 | 0.089 |
| T category [n (%)] | ||||
| T0/T1/T1a/T1b/T1mic/Tx | 85 (19.0) | 542 (26.5) | ||
| T1c | 203 (45.4) | 912 (44.6) | ||
| T2–T4 | 159 (36.6) | 591 (28.9) | 0.001 | − 0.060 |
| N category [n (%)] | ||||
| N0 | 311 (69.6) | 1525 (74.6) | ||
| N1/N1mic | 100 (22.4) | 391 (19.1) | ||
| N2/N3 | 36 (8.1) | 129 (6.3) | 0.086 | − 0.030 |
| TNM stage [n (%)] | ||||
| Stage 1 | 205 (45.9) | 1163 (56.9) | ||
| Stage 2A/2B | 204 (45.6) | 739 (36.1) | ||
| Stage 3A/3C | 34 (7.6) | 130 (6.4) | < 0.001 | − 0.064 |
| Unknown | 4 (0.9) | 13 (0.6) | ||
| Size (cm) | ||||
| Median (range) | 1.8 (0–7.5) | 1.6 (0–8) | 0.001 | |
| Unknown | 31 (7) | 72 (3.5) | ||
| Grade [n (%)] | ||||
| Grade 1 | 61 (13.6) | 440 (21.5) | ||
| Grade 2 | 149 (33.3) | 769 (37.6) | ||
| Grade 3 | 210 (47.0) | 727 (35.6) | < 0.001 | − 0.086 |
| Unknown | 27 (6.0) | 109 (5.3) | ||
| Extensive intraductal component [n (%)] | ||||
| Not present | 326 (72.9) | 1567 (76.6) | ||
| Present | 74 (16.6) | 372 (18.2) | 0.751 | 0.007 |
| Not mentioned/missing | 47 (10.5) | 106 (5.3) | ||
| Margins (mm) | ||||
| 0–5 | 215 (48.1) | 982 (48.0) | ||
| 6–10 | 112 (25.1) | 533 (26.1) | ||
| > 10 | 87 (19.5) | 442 (21.6) | 0.744 | 0.012 |
| Unknown | 33 (7.4) | 88 (4.3) | ||
| Lymphovascular invasion [n (%)] | ||||
| No | 304 (68.0) | 1562 (76.4) | ||
| Yes | 101 (22.6) | 376 (18.4) | 0.012 | − 0.052 |
| Unknown | 42 (9.4) | 107 (0.2) | ||
| No. of positive nodes | ||||
| Median (range) | 0 (0–28) | 0 (0–40) | 0.024 | − 0.045 |
| Unknown | 0 (0) | 4 (0.2) | ||
| ERa [n (%)] | ||||
| Negative | 126 (28.2) | 476 (23.3) | ||
| Positive | 284 (63.5) | 1467 (71.7) | 0.009 | 0.054 |
| Equivocal | 0 (0) | 4 (0.2) | ||
| Unknown | 37 (8.3) | 98 (4.8) | ||
| PRa [n (%)] | ||||
| Negative | 141 (31.5) | 605 (29.6) | ||
| Positive | 267 (59.7) | 1332 (65.1) | 0.190 | 0.027 |
| Equivocal | 0 (0) | 4 (0.2) | ||
| Unknown | 39 (8.7) | 104 (4.8) | ||
| HER2a [n (%)] | ||||
| Negative | 274 (61.3) | 1365 (66.7) | ||
| Positive | 82 (18.3) | 351 (17.2) | 0.276 | − 0.024 |
| Equivocal | 17 (3.8) | 91 (4.4) | ||
| Unknown | 74 (16.6) | 238 (11.6) | ||
| Histologic subtype [n (%)] | ||||
| Luminal A/B | 266 (59.5) | 1421 (69.5) | ||
| HER2 enriched | 34 (7.6) | 129 (6.3) | ||
| Basal | 68 (15.2) | 202 (9.9) | < 0.001 | 0.087 |
| Unknown | 79 (17.7) | 293 (14.3) | ||
| Chemotherapy [n (%)] | ||||
| No | 168 (37.6) | 1106 (54.1) | ||
| Yes | 277 (62.0) | 934 (45.7) | < 0.001 | − 0.126 |
| Unknown | 2 (0.4) | 5 (0.2) | ||
| First event [n (%)] | ||||
| Locoregional recurrence | 30 (6.7) | 56 (2.7) | ||
| Distant recurrence | 38 (8.5) | 91 (4.5) | ||
| New contralateral breast cancer | 17 (3.8) | 43 (2.1) | ||
| New non-breast or unknown cancers | 5 (1.1) | 40 (2.0) | ||
| Death (any cause) | 2 (0.5) | 23 (1.1) | ||
| Alive without disease | 355 (79.4) | 1792 (87.6) | < 0.001 | 0.125 |
| Follow-up time (years) | ||||
| Median (range) | 4.36 (0.18–24.83) | 4.09 (0.03–22.14) | 0.072 | − 0.036 |
Patients were staged according to the 7th edition of the American Joint Committee on Cancer (AJCC) system
ER estrogen receptor, PR progesterone receptor
aEquivocal was excluded from the test of association