Table 1. Patient characteristics before and after propensity score matching.
| Characteristics | Before matching, n (%) | After matching, n (%) | |||||
|---|---|---|---|---|---|---|---|
| PORT | Non-PORT | P value | PORT | Non-PORT | P value | ||
| Total number | 1,092 | 1,255 | 877 | 877 | |||
| Age (years) | |||||||
| <65 | 521 (47.7) | 529 (42.2) | <0.01 | 392 (44.7) | 392 (44.7) | 1 | |
| ≥65 | 571 (52.3) | 726 (57.8) | 485 (55.3) | 485 (55.3) | |||
| Sex | |||||||
| Female | 601 (55.0) | 722 (57.5) | 0.241 | 507 (57.8) | 507 (57.8) | 1 | |
| Male | 491 (45.0) | 533 (42.5) | 370 (42.2) | 370 (42.2) | |||
| Grade | |||||||
| I–II | 593 (54.3) | 691 (55.1) | 0.745 | 485 (55.3) | 485 (55.3) | 1 | |
| III–IV | 499 (45.7) | 564 (44.9) | 392 (44.7) | 392 (44.7) | |||
| Histology | |||||||
| Adenocarcinomas | 755 (69.1) | 875 (69.7) | 0.556 | 636 (72.5) | 636 (72.5) | 1 | |
| Squamous cell neoplasms | 183 (16.8) | 221 (17.6) | 134 (15.3) | 134 (15.3) | |||
| Others | 154 (14.1) | 159 (12.7) | 107 (12.2) | 107 (12.2) | |||
| AJCC T | |||||||
| T1 | 413 (37.8) | 513 (40.9) | 0.142 | 315 (35.9) | 315 (35.9) | 1 | |
| T2 | 679 (62.2) | 742 (59.1) | 562 (64.1) | 562 (64.1) | |||
| Laterality | |||||||
| Left | 472 (43.2) | 575 (45.8) | 0.223 | 372 (42.4) | 372 (42.4) | 1 | |
| Right | 620 (56.8) | 680 (54.2) | 505 (57.6) | 505 (57.6) | |||
| LNR | |||||||
| <0.31 | 562 (51.5) | 792 (63.1) | <0.001 | 497 (56.7) | 497 (56.7) | 1 | |
| ≥0.31 | 530 (48.5) | 463 (36.9) | 380 (43.3) | 380 (43.3) | |||
PORT, postoperative radiotherapy; AJCC, American Joint Committee on Cancer; LNR, lymph node ratio.