Table 1.
Patients’ baseline characteristics before and after propensity score matching.
| Variables | Before PSM | After PSM | |||||||
|---|---|---|---|---|---|---|---|---|---|
| n | No RT (%) | RT (%) | Refused RT (%) | P | n | No RT | RT | P | |
| Age (years) | |||||||||
| 70-74 | 9742 | 2276 (23.4) | 7136 (45.8) | 330 (26.0) | <0.001 | 4510 | 2255 | 2255 | 1 |
| 75-79 | 7545 | 2321 (23.9) | 4889 (31.4) | 335 (26.4) | 4590 | 2295 | 2295 | ||
| 80-84 | 5305 | 2428 (25.0) | 2569 (16.5) | 308 (24.3) | 4390 | 2195 | 2195 | ||
| ≥85 | 3994 | 2700 (27.8) | 997 (6.4) | 297 (23.4) | 1952 | 976 | 976 | ||
| Race | |||||||||
| Non-Hispanic White | 21687 | 7915 (81.4) | 12707 (81.5) | 1065 (83.9) | 0.015 | 12548 | 6274 | 6274 | 1 |
| Non-Hispanic Black | 1627 | 611 (6.3) | 957 (6.1) | 59 (4.6) | 932 | 466 | 466 | ||
| Hispanic (All Races) | 1692 | 656 (6.7) | 954 (6.1) | 82 (6.5) | 1062 | 531 | 531 | ||
| Other | 1580 | 543 (5.6) | 973 (6.2) | 64 (5.0) | 900 | 450 | 450 | ||
| Histology | |||||||||
| Invasive ductal carcinoma | 21483 | 7834 (80.6) | 12608 (80.9) | 1041 (82.0) | <0.001 | 12632 | 6313 | 6313 | 1 |
| Invasive lobular carcinoma | 2830 | 892 (9.2) | 1829 (11.7) | 109 (8.6) | 1408 | 704 | 704 | ||
| Other | 2273 | 999 (10.3) | 1154 (7.4) | 120 (9.4) | 1402 | 701 | 701 | ||
| Grade | |||||||||
| Well differentiated | 10491 | 4117 (42.3) | 5806 (37.2) | 568 (44.7) | <0.001 | 6456 | 3228 | 3228 | 1 |
| Moderately differentiated | 13127 | 4657 (47.9) | 7893 (50.6) | 577 (45.4) | 7532 | 3766 | 3766 | ||
| Poorly/undifferentiated | 2968 | 951 (9.8) | 1892 (12.1) | 125 (9.8) | 1454 | 727 | 727 | ||
| Tumor stage | |||||||||
| T1 | 22238 | 8192 (84.2) | 12974 (83.2) | 1072 (84.4) | 0.077 | 13314 | 6657 | 6657 | 1 |
| T2 | 4348 | 1533 (15.8) | 2617 (16.8) | 198 (15.6) | 2128 | 1064 | 1064 | ||
| PR status | |||||||||
| Negative | 3021 | 1045 (10.7) | 1830 (11.7) | 146 (11.5) | 0.053 | 1598 | 799 | 799 | 1 |
| Positve | 23565 | 8680 (89.3) | 13761 (88.3) | 1124 (88.5) | 13844 | 6922 | 6922 | ||
| Chemotherapy | |||||||||
| No | 25876 | 9576 (98.5) | 15039 (96.5) | 1261 (99.3) | <0.001 | 15186 | 7593 | 7593 | 1 |
| Yes | 710 | 149 (1.5) | 552 (3.5) | 9 (0.7) | 256 | 128 | 128 | ||