Table 2.
Patient characteristics
| Covariate | Statistics | Level | No Treatment N=2517 |
Resection Only N=207 |
Radiation Only N=1619 |
Chemotherapy Only N=602 |
Combination of 2 or More N=1024 |
Overall N=5969 |
|---|---|---|---|---|---|---|---|---|
| Age at BM | N (%) | 66–75 | 1122 (44.6) | 123 (59.4) | 921 (56.9) | 414 (68.8) | 689 (67.3) | 3269 (54.8) |
| N (%) | 76–85 | 1002 (39.8) | 68 (32.9) | 565 (34.9) | 167 (27.7) | 310 (30.3) | 2112 (35.4) | |
| N (%) | 86+ | 393 (15.6) | 16 (7.7) | 133 (8.2) | 21 (3.5) | 25 (2.4) | 588 (9.9) | |
| Race | N (%) | White | 2119 (84.2) | 180 (87) | 1397 (86.3) | 511 (84.9) | 910 (88.9) | 5117 (85.7) |
| N (%) | Not White | 398 (15.8) | 27 (13) | 222 (13.7) | 91 (15.1) | 114 (11.1) | 852 (14.3) | |
| Marital Status | N (%) | Married | 1193 (47.4) | 115 (55.6) | 782 (48.3) | 333 (55.3) | 576 (56.3) | 2999 (50.2) |
| N (%) | Not Married | 1324 (52.6) | 92 (44.4) | 837 (51.7) | 269 (44.7) | 448 (43.8) | 2970 (49.8) | |
| Location of Residence | N (%) | Metro | 2243 (89.1) | 191 (92.3) | 1385 (85.5) | 533 (88.5) | 875 (85.4) | 5227 (87.6) |
| N (%) | Not Metro | 274 (10.9) | 16 (7.7) | 234 (14.5) | * | * | * | |
| N (%) | Missing | 0 (0) | 0 (0) | 0 (0) | * | * | * | |
| Reason for Medicare enrollment | N (%) | Age | 2330 (92.6) | 195 (94.2) | 1512 (93.4) | 569 (94.5) | 963 (94) | 5569 (93.3) |
| N (%) | Disability or ESRD | 187 (7.4) | 12 (5.8) | 107 (6.6) | 33 (5.5) | 61 (6) | 400 (6.7) | |
| Comorbidity | N (%) | 0 | 1239 (49.2) | 129 (62.3) | 939 (58) | 365 (60.6) | 645 (63) | 3317 (55.6) |
| N (%) | 1 | 714 (28.4) | 46 (22.2) | 445 (27.5) | 162 (26.9) | 268 (26.2) | 1635 (27.4) | |
| N (%) | 2+ | 564 (22.4) | 32 (15.5) | 235 (14.5) | 75 (12.5) | 111 (10.8) | 1017 (17) | |
| Cancer Burden | N (%) | 1 | 2248 (89.3) | 181 (87.4) | 1463 (90.4) | 543 (90.2) | 919 (89.7) | 5354 (89.7) |
| N (%) | 2+ | 269 (10.7) | 26 (12.6) | 156 (9.6) | 59 (9.8) | 105 (10.3) | 615 (10.3) | |
| Extracranial Metastasis | N (%) | No | 935 (37.1) | 82 (39.6) | 176 (10.9) | 17 (2.8) | 76 (7.4) | 1286 (21.5) |
| N (%) | Yes | 1582 (62.9) | 125 (60.4) | 1443 (89.1) | 585 (97.2) | 948 (92.6) | 4683 (78.5) | |
| Stage | N (%) | In situ / Localized | 1388 (55.1) | 115 (55.6) | 620 (38.3) | 182 (30.2) | 382 (37.3) | 2687 (45) |
| N (%) | Regional | 746 (29.6) | 76 (36.7) | 581 (35.9) | 257 (42.7) | 360 (35.2) | 2020 (33.8) | |
| N (%) | Distant | 329 (13.1) | * | 388 (24) | 145 (24.1) | 258 (25.2) | * | |
| N (%) | Unknown | 54 (2.1) | * | 30 (1.9) | 18 (3) | 24 (2.3) | * | |
| ER | N (%) | ER+ | 1215 (48.3) | 86 (41.5) | 726 (44.8) | 302 (50.2) | 404 (39.5) | 2733 (45.8) |
| N (%) | ER− | 307 (12.2) | 36 (17.4) | 417 (25.8) | 131 (21.8) | 365 (35.6) | 1256 (21) | |
| N (%) | Unknown | 995 (39.5) | 85 (41.1) | 476 (29.4) | 169 (28.1) | 255 (24.9) | 1980 (33.2) | |
| PR | N (%) | PR+ | 981 (39) | 69 (33.3) | 554 (34.2) | 228 (37.9) | 288 (28.1) | 2120 (35.5) |
| N (%) | PR− | 505 (20.1) | 52 (25.1) | 573 (35.4) | 201 (33.4) | 472 (46.1) | 1803 (30.2) | |
| N (%) | Unknown | 1031 (41) | 86 (41.5) | 492 (30.4) | 173 (28.7) | 264 (25.8) | 2046 (34.3) | |
| Year of BM Diagnosis | N (%) | 1992–1996 | 545 (21.7) | 36 (17.4) | 272 (16.8) | 84 (14) | 103 (10.1) | 1040 (17.4) |
| N (%) | 1997–2002 | 635 (25.2) | 54 (26.1) | 357 (22.1) | 143 (23.8) | 216 (21.1) | 1405 (23.5) | |
| N (%) | 2003–2008 | 777 (30.9) | 71 (34.3) | 557 (34.4) | 229 (38) | 421 (41.1) | 2055 (34.4) | |
| N (%) | 2009–2012 | 560 (22.2) | 46 (22.2) | 433 (26.7) | 146 (24.3) | 284 (27.7) | 1469 (24.6) | |
| AMC Service | N (%) | No | 1500 (59.6) | 119 (57.5) | 1091 (67.4) | 375 (62.3) | 654 (63.9) | 3739 (62.6) |
| N (%) | Yes | 1017 (40.4) | 88 (42.5) | 528 (32.6) | 227 (37.7) | 370 (36.1) | 2230 (37.4) | |
| Status | N (%) | Alive | 492 (19.5) | 52 (25.1) | 90 (5.6) | 56 (9.3) | 60 (5.9) | 750 (12.6) |
| N (%) | Deceased | 2025 (80.5) | 155 (74.9) | 1529 (94.4) | 546 (90.7) | 964 (94.1) | 5219 (87.4) | |
| Age at BM | Mean | 77.0 | 74.6 | 74.8 | 73.2 | 73.1 | 75.3 | |
| Median | 76.3 | 73.7 | 73.5 | 72.2 | 72.0 | 74.1 | ||
| Interval from BC to BM (years) | Mean | 6.5 | 7.3 | 4.9 | 5.6 | 5.0 | 5.7 | |
| Median | 4.5 | 5.8 | 3.1 | 3.5 | 3.3 | 3.7 |
*
Suppressed because of small cell counts
Abbreviations: AMC, academic medical center; BC, breast cancer; BM, brain metastasis; ER, estrogen receptor; ESRD, end stage renal disease; PR, progesterone receptor.