Table 1.
Selected baseline characteristics for the SEER database study population divided per study groups before and after PSM
| Characteristics | Before PSM (2267) | After PSM (1066) | ||||
|---|---|---|---|---|---|---|
| No RT | RT | P-value | No RT | RT | P-value | |
| Age at diagnosis | < 0.05 | 0.057 | ||||
| < 60 | 504 (42.7%) | 592 (54.5%) | 264 (49.5%) | 296 (55.5%) | ||
| ≥ 60 | 677 (57.3%) | 494 (45.5%) | 269 (50.5%) | 237 (44.5%) | ||
| Ethnicity | < 0.05 | 0.667 | ||||
| White | 929 (78.7%) | 825 (76.0%) | 402 (75.4%) | 408 (76.5%) | ||
| Black | 163 (13.8%) | 190 (17.5%) | 95 (17.8%) | 85 (15.9%) | ||
| Others | 89 (7.5%) | 71 (6.5%) | 36 (6.8%) | 40 (7.5%) | ||
| Marital status | 0.263 | 0.736 | ||||
| Single | 185 (15.7%) | 151 (13.9%) | 86 (16.1%) | 81 (15.2%) | ||
| Married | 996 (84.3%) | 935 (86.1%) | 447 (83.9%) | 452 (84.8%) | ||
| Grade | 0.539 | 0.472 | ||||
| G1 | 64 (5.4%) | 56 (5.2%) | 23 (4.3%) | 24 (4.5%) | ||
| G2 | 173 (14.6%) | 137 (12.6%) | 66 (12.4%) | 69 (12.9%) | ||
| G3 | 888 (75.2%) | 839 (77.3%) | 416 (78.0%) | 400 (75.0%) | ||
| G4 | 56 (4.7%) | 54 (5.0%) | 28 (5.3%) | 40 (7.5%) | ||
| ER status | 0.413 | 0.456 | ||||
| Negative | 979 (82.9%) | 885 (81.5%) | 451 (84.6%) | 441 (82.7%) | ||
| Positive | 202 (17.1%) | 201 (18.5%) | 82 (15.4%) | 92 (17.3%) | ||
| PR status | 0.058 | 0.192 | ||||
| Negative | 1044 (88.4%) | 930 (85.6%) | 475 (89.1%) | 460 (86.3%) | ||
| Positive | 137 (11.6%) | 156 (14.4%) | 58 (10.9%) | 73 (13.7%) | ||
| Stage T | < 0.05 | 0.457 | ||||
| ≤ 5 cm | 937 (79.3%) | 814 (75.0%) | 373 (70.0%) | 385 (72.2%) | ||
| > 5 cm | 244 (20.7%) | 272 (25.0%) | 160 (30.0%) | 148 (27.8%) | ||
| Stage N | 0.090 | 0.202 | ||||
| N0 | 929 (78.7%) | 811 (74.7%) | 381 (71.5%) | 382 (71.7%) | ||
| N1 | 173 (14.6%) | 195 (18.0%) | 96 (18.0%) | 112 (21.0%) | ||
| N2 | 51 (4.3%) | 45 (4.1%) | 35 (6.6%) | 22 (4.1%) | ||
| N3 | 28 (2.4%) | 35 (3.2%) | 21 (3.9%) | 17 (3.2%) | ||
| Stage TNM | < 0.05 | 0.848 | ||||
| I | 247 (20.9%) | 283 (26.1%) | 109 (20.5%) | 115 (21.6%) | ||
| II | 779 (66.0%) | 605 (55.7%) | 314 (58.9%) | 314 (58.9%) | ||
| III | 155 (13.1%) | 198 (18.2%) | 110 (20.6%) | 104 (19.5%) | ||
| Breast operation | < 0.05 | 0.667 | ||||
| Lumpectomy | 254 (21.5%) | 692 (63.7%) | 248 (46.5%) | 240 (45.0%) | ||
| Mastectomy | 927 (78.5%) | 394 (36.3%) | 285 (53.5%) | 293 (55.0%) | ||
| Chemotherapy | < 0.05 | 0.111 | ||||
| Not done/unknown | 548 (46.4%) | 254 (23.4%) | 176 (33.0%) | 151 (28.3%) | ||
| Done | 633 (53.6%) | 832 (76.6%) | 357 (67.0%) | 382 (71.7%) | ||
| Axilla LN operation | 0.050 | 0.425 | ||||
| SLNB | 581 (49.2%) | 580 (53.4%) | 261 (49.0%) | 247 (46.3%) | ||
| ALND | 600 (50.8%) | 506 (46.6%) | 272 (51.0%) | 286 (53.7%) | ||
SLNB Sentinel lymph node biopsy, ALND axillary lymph node dissection
Significant results are in italic