Table I.
Patient characteristics at the initial diagnosis of breast cancer in the BOM (n=208) and non-BOM (n=1,082) groups.
| Characteristic | BOM group | non-BOM group | P-value |
|---|---|---|---|
| Median age at primary diagnosis (range), years | 48 (24–72) | 48 (21–78) | 0.978 |
| Median age at metastasis or recurrence (range), years | 50 (24–78) | 52 (25–80) | 0.262 |
| Menopausal status, n (%) | 0.062 | ||
| Premenopause | 116 (55.8) | 527 (48.7) | |
| Postmenopause | 92 (44.2) | 555 (51.3) | |
| Lymph node status, n (%) | 0.838 | ||
| Negative | 61 (29.3) | 325 (30.0) | |
| Positive | 147 (70.7) | 757 (70.0) | |
| Tumor stage, n (%) | 0.392 | ||
| T1 | 53 (25.5) | 329 (30.4) | |
| T2 | 103 (49.5) | 515 (47.6) | |
| T3 | 34 (16.3) | 141 (13.0) | |
| T4 | 18 (8.7) | 97 (9.0) | |
| Clinical stage, n (%) | <0.001 | ||
| I | 24 (11.5) | 151 (14.0) | |
| II | 75 (36.1) | 447 (41.3) | |
| III | 61 (29.3) | 382 (35.3) | |
| IV | 48 (23.1) | 102 (9.4) | |
| Tumor type, n (%) | 0.273 | ||
| Invasive ductal carcinoma | 170 (81.7) | 917 (84.8) | |
| Others | 38 (18.3) | 165 (15.2) | |
| HR status, n (%) | <0.001 | ||
| Negative | 39 (18.7) | 422 (39.0) | |
| Positive | 169 (81.3) | 660 (61.0) | |
| HER2 status, n (%) | |||
| Negative | 171 (82.2) | 814 (75.2) | 0.030 |
| Positive | 37 (17.8) | 268 (24.8) | |
| Molecular type, n (%) | <0.001 | ||
| HR+/HER2− | 144 (69.2) | 538 (49.7) | |
| HR/HER2+ | 40 (19.3) | 268 (24.8) | |
| HR−/HER2− | 24 (11.5) | 276 (25.5) |
HER2, human epidermal growth factor receptor 2; HR, hormone receptor; BOM, bone-only metastases.