Table 1.
Characteristics of patients before and after PSM according to whether or not surgery.
| Characteristics | Entire patients | Propensity-matched patients | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Surgery (+) | Surgery (−) | P value | Surgery (+) | Surgery (−) | P value | |||||
| (n = 2008) | % | (n = 1932) | % | (n = 1192) | % | (n = 1192) | % | |||
| Age at diagnosis | <.001 | .343 | ||||||||
| 23–66 | 1304 | 64.9 | 944 | 48.8 | 660 | 55.37 | 661 | 55.45 | ||
| 67–74 | 473 | 23.5 | 481 | 24.8 | 329 | 27.60 | 305 | 25.59 | ||
| 75–97 | 231 | 11.5 | 507 | 26.2 | 203 | 17.03 | 226 | 18.96 | ||
| Gender | <.001 | .756 | ||||||||
| Female | 308 | 15.3 | 456 | 23.6 | 234 | 19.63 | 227 | 19.04 | ||
| Male | 1700 | 84.6 | 1476 | 76.3 | 958 | 80.37 | 965 | 80.96 | ||
| Tumor size (mm) | <.001 | .799 | ||||||||
| 1–44 | 926 | 46.1 | 647 | 33.4 | 462 | 38.76 | 472 | 39.60 | ||
| 45–70 | 764 | 38.0 | 807 | 41.7 | 484 | 40.60 | 468 | 39.26 | ||
| 71–550 | 318 | 15.8 | 478 | 24.7 | 246 | 20.64 | 252 | 21.14 | ||
| Marital status | <.001 | .313 | ||||||||
| Unmarried | 632 | 31.4 | 861 | 44.5 | 475 | 39.85 | 450 | 37.75 | ||
| Married | 1376 | 68.5 | 1071 | 55.4 | 717 | 60.15 | 742 | 62.25 | ||
| Race | <.001 | .573 | ||||||||
| White | 1806 | 89.9 | 1506 | 77.9 | 1021 | 85.65 | 1005 | 84.31 | ||
| Black | 114 | 5.6 | 283 | 14.6 | 95 | 7.97 | 109 | 9.14 | ||
| Other | 88 | 4.3 | 143 | 7.4 | 76 | 6.38 | 78 | 6.54 | ||
| Grade | <.001 | .857 | ||||||||
| Well differentiated; Grade I | 82 | 4 | 116 | 6.0 | 66 | 5.54 | 64 | 5.37 | ||
| Moderately differentiated; Grade II | 779 | 38.7 | 843 | 43.6 | 493 | 41.36 | 485 | 40.69 | ||
| Poorly differentiated; Grade III | 1108 | 55.1 | 936 | 48.4 | 605 | 50.76 | 620 | 52.01 | ||
| Undifferentiated; anaplastic; Grade IV | 39 | 1.9 | 37 | 1.9 | 28 | 2.35 | 23 | 1.93 | ||
| T-stage | <.001 | .372 | ||||||||
| T3 | 1730 | 81.6 | 1184 | 61.2 | 923 | 77.43 | 942 | 79.03 | ||
| T4 | 278 | 13.8 | 748 | 38.7 | 269 | 22.57 | 250 | 20.97 | ||
| N-stage | <.001 | .464 | ||||||||
| N0 | 86 | 4.2 | 320 | 16.5 | 86 | 7.21 | 76 | 6.38 | ||
| N1 | 1922 | 95.7 | 1612 | 83.4 | 1106 | 92.79 | 1116 | 93.62 | ||
| Radiation recode | .010 | .046 | ||||||||
| YES | 1549 | 77.1 | 1556 | 80.5 | 914 | 76.68 | 955 | 80.12 | ||
| None/Unknown | 459 | 22.8 | 376 | 19.4 | 278 | 23.32 | 237 | 19.88 | ||
| Chemotherapy recode | <.001 | .08 | ||||||||
| YES | 1684 | 83.8 | 1526 | 78.9 | 957 | 80.29 | 991 | 83.14 | ||
| No/Unknown | 324 | 16.1 | 406 | 21.0 | 235 | 19.71 | 201 | 16.86 | ||
| Primary_site | <.001 | <.001 | ||||||||
| Upper | 31 | 1.5 | 186 | 9.6 | 25 | 2.10 | 69 | 5.79 | ||
| Middle | 198 | 9.8 | 417 | 21.5 | 171 | 14.35 | 199 | 16.69 | ||
| Lower | 1583 | 78.8 | 967 | 50.0 | 875 | 73.41 | 695 | 58.31 | ||
| Other | 196 | 9.7 | 362 | 18.7 | 121 | 10.15 | 229 | 19.21 | ||
| Histologic | <.001 | <.001 | ||||||||
| Adenocarcinoma | 1381 | 68.7 | 777 | 40.2 | 682 | 57.21 | 603 | 50.59 | ||
| Squamous cell carcinoma | 371 | 18.4 | 947 | 49.0 | 305 | 25.59 | 480 | 40.27 | ||
| Other | 256 | 12.7 | 208 | 10.7 | 205 | 17.20 | 109 | 9.14 | ||
The optimal cutoffs for age and tumor size were determined according to X-tile v3.6.1. Most variables did not show remarkably statistical differences between surgery and nonsurgery (P > .05) in the postPSM cohort.
PSM = propensity score matching.