Table 1.
Study cohort of patients with breast cancer with BM (N=2427) by stage of disease at BC diagnosis
| Stage of disease at BC diagnosis |
|||||
|---|---|---|---|---|---|
| Localised BC N=420 N (%) |
Regional BC N=1204 N (%) |
Metastatic BC N=606 N (%) |
Unknown N=197 N (%) |
Overall N=2427 N (%) |
|
| Age at BC diagnosis (years) | |||||
| 25–49 | 94 (22%) | 319 (27%) | 89 (15%) | 30 (15%) | 532 (22%) |
| 50–59 | 103 (25%) | 340 (28%) | 129 (21%) | 45 (23%) | 617 (25%) |
| 60–69 | 120 (29%) | 321 (27%) | 201 (33%) | 56 (28%) | 698 (29%) |
| ≥70 | 103 (25%) | 224 (19%) | 187 (31%) | 66 (34%) | 580 (24%) |
| Time period of BC diagnosis | |||||
| 1997–2001 | 211 (50%) | 492 (41%) | 135 (22%) | 36 (18%) | 874 (36%) |
| 2002–2006 | 161 (38%) | 528 (44%) | 242 (40%) | 80 (41%) | 1011 (42%) |
| 2007–2011 | 48 (11%) | 184 (15%) | 229 (38%) | 81 (41%) | 542 (22%) |
| Hormone receptor and HER2 status | |||||
| ER-positive | 313 (75%) | 890 (74%) | 500 (83%) | 156 (79%) | 1859 (77%) |
| ER-negative | 99 (24%) | 295 (25%) | 98 (16%) | 35 (18%) | 527 (22%) |
| Unknown | 8 (2%) | 19 (2%) | 8 (1%) | 6 (3%) | 41 (2%) |
| ER/PR-positive and HER2-negative | 61 (15%) | 200 (17%) | 180 (30%) | 50 (25%) | 491 (20%) |
| HER2-positive (any ER/PR status) | 46 (11%) | 216 (18%) | 97 (16%) | 34 (17%) | 393 (16%) |
| ER/PR-negative and HER2-negative | 42 (10%) | 128 (11%) | 51 (8%) | 17 (9%) | 238 (10%) |
| Unknown | 271 (65%) | 660 (55%) | 278 (46%) | 96 (49%) | 1305 (54%) |
| Charlson Comorbidity Index score | |||||
| 0 | 316 (75%) | 925 (77%) | 476 (79%) | 145 (74%) | 1862 (77%) |
| 1–2 | 87 (21%) | 245 (20%) | 111 (18%) | 42 (21%) | 485 (20%) |
| >2 | 17 (4%) | 34 (3%) | 19 (3%) | 10 (5%) | 80 (3%) |
| Median age (range) at BM diagnosis | 64 years (28–92) | 62 years (28–97) | 65 years (28–95) | 67 years (34–92) | 63 years (28–97) |
| Length of BMFI | |||||
| 0 to <1 year | 79 (19%) | 264 (22%) | 491 (81%) | 84 (43%) | 918 (38%) |
| 1 to <3 years | 131 (31%) | 426 (35%) | 71 (12%) | 58 (29%) | 686 (28%) |
| 3 to <5 years | 108 (26%) | 281 (23%) | 38 (6%) | 35 (18%) | 462 (19%) |
| ≥5 years | 102 (24%) | 233 (19%) | 6 (1%) | 20 (10%) | 361 (15%) |
| 25th centile | 1.43 years | 1.16 years | 0.02 years | 0.12 years | 0.16 years |
| Median | 3.01 years | 2.54 years | 0.07 years | 1.52 years | 1.85 years |
| 75th centile | 4.87 years | 4.34 years | 0.44 years | 3.30 years | 3.78 years |
| Other metastases recorded at or before BM diagnosis | 200 (48%) | 691 (57%) | 296 (49%) | 105 (53%) | 1292 (53%) |
| Skeletal-related events at BM diagnosis* | |||||
| Radiation to bone | 81 (19%) | 258 (21%) | 124 (20%) | 21 (11%) | 484 (20%) |
| Pathological fracture | 11 (3%) | 41 (3%) | 14 (2%) | 1 (1%) | 67 (3%) |
| Spinal cord compression | 12 (3%) | 33 (3%) | 12 (2%) | 6 (3%) | 63 (3%) |
| Surgery to bone | 10 (2%) | 29 (2%) | 19 (3%) | 5 (3%) | 63 (3%) |
*Categories not mutually exclusive.
BC, breast cancer; BM, bone metastasis; BMFI, bone metastasis-free interval; ER, estrogen receptor; HER2, human epidermal growth factor receptor 2; PR, progesterone receptor.