Table 2.
Characteristics of patients before and after PSM according to whether or not PORT.
| Characteristics | Entire patients | Propensity-matched patients | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| PORT(+) | PORT(−) | P value | PORT (+) | PORT(−) | P value | |||||
| (n = 322) | % | (n = 1686) | % | (n = 318) | % | (n = 318) | % | |||
| Age | .236 | .231 | ||||||||
| 23–66 | 219 | 68.0 | 1085 | 64.35 | 216 | 67.92 | 212 | 66.67 | ||
| 67–74 | 64 | 19.88 | 409 | 24.26 | 64 | 20.13 | 78 | 24.53 | ||
| 75–97 | 39 | 12.11 | 192 | 11.39 | 38 | 11.95 | 28 | 8.81 | ||
| Gender | .311 | .651 | ||||||||
| Female | 43 | 13.35 | 265 | 15.72 | 43 | 13.52 | 48 | 15.09 | ||
| Male | 279 | 86.65 | 1421 | 84.28 | 275 | 86.48 | 270 | 84.91 | ||
| Tumor size (mm) | .858 | .688 | ||||||||
| 1–44 | 153 | 47.52 | 773 | 45.85 | 152 | 47.80 | 142 | 44.65 | ||
| 45–70 | 119 | 37.0 | 645 | 38.26 | 116 | 36.48 | 120 | 37.74 | ||
| 71–550 | 50 | 15.53 | 268 | 15.90 | 50 | 15.72 | 56 | 17.61 | ||
| Marital status | .964 | .796 | ||||||||
| Unmarried | 101 | 31.37 | 531 | 31.49 | 98 | 30.82 | 94 | 29.56 | ||
| Married | 221 | 68.63 | 1155 | 68.51 | 220 | 69.18 | 224 | 70.44 | ||
| Race | .064 | .132 | ||||||||
| White | 283 | 87.89 | 1523 | 90.33 | 280 | 88.05 | 277 | 87.11 | ||
| Black | 27 | 8.39 | 87 | 5.16 | 26 | 8.18 | 19 | 5.97 | ||
| Other | 12 | 3.73 | 76 | 4.51 | 12 | 3.77 | 22 | 6.91 | ||
| Grade | .131 | .169 | ||||||||
| Grade I | 16 | 4.97 | 66 | 3.9 | 16 | 5.03 | 6 | 1.89 | ||
| Grade II | 117 | 36.34 | 662 | 39.26 | 115 | 36.16 | 117 | 36.79 | ||
| Grade III | 178 | 55.28 | 930 | 55.16 | 176 | 55.35 | 186 | 58.49 | ||
| Grade IV | 11 | 3.42 | 28 | 1.66 | 11 | 3.46 | 9 | 2.83 | ||
| T stage | .112 | .826 | ||||||||
| T3 | 268 | 83.23 | 1462 | 86.71 | 268 | 84.28 | 271 | 85.22 | ||
| T4 | 54 | 16.77 | 224 | 13.29 | 50 | 15.72 | 47 | 14.78 | ||
| N stage | .132 | .317 | ||||||||
| N0 | 19 | 5.90 | 67 | 3.97 | 16 | 5.03 | 10 | 3.14 | ||
| N1 | 303 | 94.10 | 1619 | 96.03 | 302 | 94.97 | 308 | 96.86 | ||
| Chemotherapy recode | .005 | .796 | ||||||||
| Yes | 287 | 89.13 | 1397 | 82.86 | 283 | 88.99 | 286 | 89.94 | ||
| No | 35 | 10.87 | 289 | 17.1 | 35 | 11.01 | 32 | 10.06 | ||
| Primary_site | .06 | .190 | ||||||||
| Upper | 8 | 2.48 | 23 | 1.36 | 8 | 2.52 | 3 | 0.94 | ||
| Middle | 28 | 8.70 | 170 | 10.08 | 28 | 8.81 | 36 | 11.32 | ||
| Lower | 244 | 75.78 | 1339 | 79.4 | 241 | 75.79 | 248 | 77.99 | ||
| Other | 42 | 13.04 | 154 | 9.13 | 41 | 12.89 | 31 | 9.75 | ||
| Histologic | .215 | .726 | ||||||||
| Adenocarcinoma | 209 | 64.91 | 1172 | 69.51 | 207 | 65.09 | 199 | 62.58 | ||
| Squamous cell carcinoma | 64 | 19.88 | 307 | 18.2 | 63 | 19.81 | 64 | 20.13 | ||
| Other | 49 | 15.22 | 207 | 12.28 | 48 | 15.09 | 55 | 17.30 | ||
Although most variables did not show statistical differences between PORT(+) and PORT(−) (P > .05), we still performed PSM to remove potential effects of other variables.
PORT = postoperative radiotherapy, PSM = propensity score matching.