TABLE 1.
Patients’ demographics, clinical characteristics, and therapeutic interventions among bone metastatic breast cancer patients.
| Characteristic | Overall | Groups | p | |
|---|---|---|---|---|
| Training cohort | Validation cohort | |||
| n | 16,189 | 14,582 | 1,607 | |
| Age, mean (SD) | 61.67 (14.04) | 61.65 (14.04) | 61.87 (14.10) | 0.547 |
| Sex (%) | 0.116 | |||
| Female | 15,998 (98.8) | 14,403 (98.8) | 1,595 (99.3) | |
| Male | 191 (1.2) | 179 (1.2) | 12 (0.7) | |
| Race (%) | 0.368 | |||
| American Indian/Alaska Native | 105 (0.6) | 92 (0.6) | 13 (0.8) | |
| Asian or Pacific Islander | 1,218 (7.5) | 1,104 (7.6) | 114 (7.1) | |
| Black | 2,356 (14.6) | 2,130 (14.6) | 226 (14.1) | |
| White | 12453 (76.9) | 11201 (76.8) | 1,252 (77.9) | |
| Unknown | 57 (0.4) | 55 (0.4) | 2 (0.1) | |
| Marital status (%) | 0.866 | |||
| Married (which includes common law) | 7,055 (43.6) | 6,370 (43.7) | 685 (42.6) | |
| Separated, divorced, or widowed | 4,627 (28.6) | 4,157 (28.5) | 470 (29.2) | |
| Single (never married) | 3,554 (22.0) | 3,199 (21.9) | 355 (22.1) | |
| Others | 953 (5.9) | 856 (5.9) | 97 (6.0) | |
| Geographic areas (%) | 0.800 | |||
| Metropolitan counties | 14,345 (88.6) | 12,927 (88.7) | 1,418 (88.2) | |
| Nonmetropolitan counties | 1,821 (11.2) | 1,635 (11.2) | 186 (11.6) | |
| Unknown | 23 (0.1) | 20 (0.1) | 3 (0.2) | |
| Laterality (%) | 0.575 | |||
| Bilateral, single primary | 95 (0.6) | 90 (0.6) | 5 (0.3) | |
| Left—origin of primary | 7,734 (47.8) | 6,970 (47.8) | 764 (47.5) | |
| Only one side—side unspecified | 55 (0.3) | 48 (0.3) | 7 (0.4) | |
| Paired site, but no information concerning laterality | 776 (4.8) | 697 (4.8) | 79 (4.9) | |
| Right—origin of primary | 7,529 (46.5) | 6,777 (46.5) | 752 (46.8) | |
| Brain metastasis (%) | 0.179 | |||
| No | 14,443 (89.2) | 13,031 (89.4) | 1,412 (87.9) | |
| Unknown | 569 (3.5) | 504 (3.5) | 65 (4.0) | |
| Yes | 1,177 (7.3) | 1,047 (7.2) | 130 (8.1) | |
| Liver metastasis (%) | 0.609 | |||
| No | 12,043 (74.4) | 10,843 (74.4) | 1,200 (74.7) | |
| Unknown | 422 (2.6) | 375 (2.6) | 47 (2.9) | |
| Yes | 3,724 (23.0) | 3,364 (23.1) | 360 (22.4) | |
| Lung metastasis (%) | 0.823 | |||
| No | 11,422 (70.6) | 10,279 (70.5) | 1,143 (71.1) | |
| Unknown | 563 (3.5) | 506 (3.5) | 57 (3.5) | |
| Yes | 4,204 (26.0) | 3,797 (26.0) | 407 (25.3) | |
| T stage (%) | 0.754 | |||
| T0 | 346 (2.1) | 313 (2.1) | 33 (2.1) | |
| T1 | 1,841 (11.4) | 1,655 (11.3) | 186 (11.6) | |
| T2 | 4,219 (26.1) | 3,795 (26.0) | 424 (26.4) | |
| T3 | 2,233 (13.8) | 2,004 (13.7) | 229 (14.3) | |
| T4 | 4,453 (27.5) | 4,037 (27.7) | 416 (25.9) | |
| TX | 3,097 (19.1) | 2,778 (19.1) | 319 (19.9) | |
| N stage (%) | 0.132 | |||
| N0 | 3,881 (24.0) | 3,468 (23.8) | 413 (25.7) | |
| N1 | 6,894 (42.6) | 6,255 (42.9) | 639 (39.8) | |
| N2 | 1,443 (8.9) | 1,297 (8.9) | 146 (9.1) | |
| N3 | 1,919 (11.9) | 1,730 (11.9) | 189 (11.8) | |
| NX | 2,052 (12.7) | 1,832 (12.6) | 220 (13.7) | |
| Histologic type (%) | 0.471 | |||
| Adenomas and adenocarcinomas | 1,080 (6.7) | 973 (6.7) | 107 (6.7) | |
| Ductal and lobular neoplasms | 13,557 (83.7) | 12,205 (83.7) | 1,352 (84.1) | |
| Epithelial neoplasms, NOS | 1,075 (6.6) | 967 (6.6) | 108 (6.7) | |
| Squamous cell neoplasms | 16 (0.1) | 14 (0.1) | 2 (0.1) | |
| Unspecified neoplasms | 388 (2.4) | 352 (2.4) | 36 (2.2) | |
| Others | 73 (0.5) | 71 (0.5) | 2 (0.1) | |
| Grade (%) | 0.624 | |||
| Grade I | 855 (5.3) | 767 (5.3) | 88 (5.5) | |
| Grade II | 4,170 (25.8) | 3,738 (25.6) | 432 (26.9) | |
| Grade III | 3,705 (22.9) | 3,357 (23.0) | 348 (21.7) | |
| Grade IV | 55 (0.3) | 51 (0.3) | 4 (0.2) | |
| Unknown | 7,404 (45.7) | 6,669 (45.7) | 735 (45.7) | |
| ER status (%) | 0.193 | |||
| Borderline/unknown | 1,483 (9.2) | 1,338 (9.2) | 145 (9.0) | |
| Negative | 2,385 (14.7) | 2,172 (14.9) | 213 (13.3) | |
| Positive | 12,321 (76.1) | 11,072 (75.9) | 1,249 (77.7) | |
| PR status (%) | 0.867 | |||
| Borderline/unknown | 1,656 (10.2) | 1,497 (10.3) | 159 (9.9) | |
| Negative | 4,633 (28.6) | 4,167 (28.6) | 466 (29.0) | |
| Positive | 9,900 (61.2) | 8,918 (61.2) | 982 (61.1) | |
| HER2 (%) | 0.165 | |||
| Borderline/unknown | 2,230 (13.8) | 2,001 (13.7) | 229 (14.3) | |
| Negative | 10,885 (67.2) | 9,784 (67.1) | 1,101 (68.5) | |
| Positive | 3,074 (19.0) | 2,797 (19.2) | 277 (17.2) | |
| Cancer-directed surgery (%) | 0.849 | |||
| No | 12,296 (76.0) | 11,077 (76.0) | 1,219 (75.9) | |
| Unknown | 274 (1.7) | 244 (1.7) | 30 (1.9) | |
| Yes | 3,619 (22.4) | 3,261 (22.4) | 358 (22.3) | |
| Radiation (%) | 0.862 | |||
| No/unknown | 10,725 (66.2) | 9,664 (66.3) | 1,061 (66.0) | |
| Yes | 5,464 (33.8) | 4,918 (33.7) | 546 (34.0) | |
| Chemotherapy (%) | 0.104 | |||
| No/unknown | 7,642 (47.2) | 6,852 (47.0) | 790 (49.2) | |
| Yes | 8,547 (52.8) | 7,730 (53.0) | 817 (50.8) | |
| Early death (%) | 0.329 | |||
| No | 13,374 (82.6) | 12,061 (82.7) | 1,313 (81.7) | |
| Yes | 2,815 (17.4) | 2,521 (17.3) | 294 (18.3) | |
SD, standard deviation; T, tumor; N, nodes; NOS, not otherwise specified; ER, estrogen receptor; PR, progesterone receptor; HER2, human epidermal growth factor receptor-2.