Table 1 The patient demographics and clinic-pathologic characteristics before and after PSM.
Demographic or characteristic | Before PSM | After PSM | ||||||
|---|---|---|---|---|---|---|---|---|
Total | Surgery | Non-surgery | P-value | Total | Surgery | Non-surgery | P-value | |
n = 7759 | n = 3199 (N%) | n = 4560 (N%) | n = 2036 | n = 1018 (N%) | n = 1018 (N%) | |||
Age | ||||||||
  < 60 | 3962 | 1777 (55.5%) | 2185 (47.9%) |  < 0.001 | 1067 | 533 (52.4%) | 534 (52.5%) | 0.965 |
  ≥ 60 | 3797 | 1422 (44.5%) | 2375 (52.1%) | 969 | 485 (47.6%) | 484 (47.5%) | ||
Race | ||||||||
 White | 5756 | 2377 (74.3%) | 3379 (74.1%) | 0.229 | 1519 | 763 (75%) | 756 (74.3%) | 0.357 |
 Black | 1349 | 536 (16.8%) | 813 (17.8%) | 321 | 166 (16.3%) | 155 (15.2%) | ||
 Other1 | 654 | 286 (8.9%) | 368 (8.1%) | 196 | 89 (8.7%) | 107 (10.5%) | ||
Sex | ||||||||
 Male | 93 | 43 (1.3%) | 50 (1.1%) | 0.324 | 22 | 14 (1.4%) | 8 (0.8%) | 0.198 |
 Female | 7666 | 3156 (98.7%) | 4510 (98.9%) | 2014 | 1004 (98.6%) | 1010 (99.2%) | ||
Year of diagnosis | ||||||||
 2010–2012 | 3594 | 1716 (53.6%) | 1878 (41.2%) |  < 0.001 | 993 | 498 (48.9%) | 495 (48.6%) | 0.894 |
 2013–2015 | 4165 | 1483 (46.4%) | 2682 (58.8%) | 1043 | 520 (51.1%) | 523 (51.4%) | ||
Socioeconomic status | ||||||||
 High SES | 3136 | 1212 (37.9%) | 1924 (42.2%) |  < 0.001 | 735 | 362 (35.6%) | 373 (63.6%) | 0.612 |
 Low SES | 4623 | 1987 (62.1%) | 2636 (57.8%) |  | 1301 | 656 (64.4%) | 645 (63.4%) | |
Grade | ||||||||
 Grade I | 549 | 182 (5.7%) | 367 (8.0%) |  < 0.001 | 85 | 45 (4.4%) | 40 (3.9%) | 0.684 |
 Grade II | 3135 | 1084 (33.9%) | 2051 (45.0%) | 875 | 429 (42.1%) | 446 (43.8%) | ||
 Grade III | 4025 | 1911 (59.7%) | 2114 (46.4%) | 1076 | 544 (53.4%) | 532 (52.3%) | ||
 Grade IV | 50 | 22 (0.7%) | 28 (0.6%) | 0 | 0 (0%) | 0 (0%) | ||
Tumor size (mm) | ||||||||
  < 20 | 937 | 354 (11.1%) | 583 (12.8%) | 0.047 | 180 | 94 (9.2%) | 86 (8.4%) | 0.100 |
 20–50 | 3880 | 1637 (51.2%) | 2243 (49.2%) | 1128 | 540 (53.0%) | 588 (57.8%) | ||
  > 50 | 2942 | 1208 (37.8%) | 1734 (38%) | 728 | 384 (37.7%) | 344 (33.8%) | ||
T stage | ||||||||
 T1 | 948 | 368 (11.5%) | 580 (12.7%) |  < 0.001 | 188 | 96 (9.4%) | 92 (9.0%) | 0.821 |
 T2 | 2879 | 1300 (40.6%) | 1579 (34.6%) | 876 | 428 (42.0%) | 448 (44.0%) | ||
 T3 | 1498 | 616 (19.3%) | 882 (19.3%) | 310 | 160 (15.7%) | 150 (14.7%) | ||
 T4 | 2434 | 915 (28.6%) | 1519 (33.3%) | 662 | 334 (32.8%) | 328 (32.2%) | ||
N stage | ||||||||
 N0 | 1655 | 520 (16.3%) | 1135 (24.9%) |  < 0.001 | 401 | 203 (19.9%) | 198 (19.4%) | 0.681 |
 N1 | 3649 | 1218 (38.1%) | 2431 (53.3%) | 1050 | 521 (51.2%) | 529 (52.0%) | ||
 N2 | 1064 | 653 (20.4%) | 411 (9.0%) | 231 | 123 (12.1%) | 108 (10.6%) | ||
 N3 | 1391 | 808 (25.3%) | 583 (12.8%) | 354 | 171 (16.8%) | 183 (18.0%) | ||
Chemotherapy | ||||||||
 Yes | 2938 | 931 (29.1%) | 2007 (44.0%) |  < 0.001 | 778 | 395 (38.8%) | 383 (37.6%) | 0.584 |
 No/unknown | 4821 | 2268 (70.9%) | 2553 (56.0%) | 1258 | 623 (61.2%) | 635 (62.4%) | ||
Radiotherapy | ||||||||
 Yes | 4967 | 1711 (53.5%) | 3256 (71.4%) |  < 0.001 | 1391 | 694 (68.2%) | 697 (68.5%) | 0.886 |
 No/unknown | 2792 | 1488 (46.5%) | 1304 (28.6%) | 645 | 324 (31.8%) | 321 (31.5%) | ||
Metastasis pattern (yes vs. no) | ||||||||
 Liver metastasis | 1965 | 633 (19.8%) | 1332 (29.2%) |  < 0.001 | 335 | 161 (15.8%) | 174 (17.1%) | 0.437 |
 Brain metastasis | 473 | 113 (3.5%) | 360 (7.9%) |  < 0.001 | 35 | 17 (1.7%) | 18 (1.8%) | 0.865 |
 Bone metastasis | 4947 | 1805 (56.4%) | 3142 (68.9%) |  < 0.001 | 1336 | 670 (65.8%) | 666 (65.4%) | 0.852 |
 Lung metastasis | 2367 | 791 (24.7%) | 1576 (34.6%) |  < 0.001 | 505 | 237 (23.3%) | 268 (26.3%) | 0.112 |
 Multiple sites | 2295 | 579 (18.1%) | 1716 (37.6%) |  < 0.001 | 353 | 174 (17.1%) | 179 (17.6%) | 0.770 |
Breast subtype | ||||||||
 HR + /HER2- | 4445 | 1730 (54.0%) | 2720 (59.5%) |  < 0.001 | 1329 | 661 (64.9%) | 668 (65.6%) | 0.727 |
 HR + /HER2 +  | 1383 | 569 (17.8%) | 819 (17.9%) | 295 | 142 (13.9%) | 153 (15.0%) | ||
 HR-/HER2 +  | 739 | 325 (10.1%) | 411 (9.0%) | 154 | 79 (7.8%) | 75 (7.4%) | ||
 HR-/HER2- | 1192 | 581 (18.1%) | 618 (13.5%) | 258 | 136 (13.4%) | 122 (12.0%) | ||
Location | ||||||||
 Central2 | 562 | 233 (7.3%) | 329 (7.2%) | 0.536 | 132 | 74 (7.3%) | 58 (5.7%) | 0.638 |
 Upper | 2684 | 1111 (34.7%) | 1573 (34.5%) | 687 | 340 (33.4%) | 347 (34.1%) | ||
 Lower | 823 | 353 (11.0%) | 470 (10.3%) | 231 | 115 (11.3%) | 116 (11.4%) | ||
 Axillary tail | 48 | 22 (0.7%) | 26 (0.6%) | 11 | 5 (0.5%) | 6 (0.6%) | ||
 Overlapping | 1750 | 733 (22.9%) | 1017 (22.3%) | 476 | 245 (24.1%) | 231 (22.7%) | ||
 Other3 | 1892 | 747 (23.4%) | 1145 (25.1%) | 499 | 239 (23.5%) | 260 (25.5%) | ||
Marital status | ||||||||
 Unmarried | 4057 | 1528 (47.8%) | 2529 (55.5%) |  < 0.001 | 1065 | 536 (52.7%) | 529 (52.0%) | 0.756 |
 Married | 3702 | 1671 (52.2%) | 2031 (44.5%) | 971 | 482 (47.3%) | 489 (48.0%) | ||
