Table 1.
General characteristics of patients with oral cavity squamous cell carcinoma enrolled from Hospital 1 and Hospital 2 before (n = 3028) and after (n = 1598) propensity score matching.
| Before PS matching | After PS matching | ||||||
|---|---|---|---|---|---|---|---|
| Characteristic (n, %; before PS matching) | Hospital 1 (n = 2009)n (%) | Hospital 2 (n = 1019)n (%) | SMD (%) | p a | Hospital 1 (n = 799)n (%) | Hospital 2 (n = 799)n (%) | SMD (%) |
| Margin status (mm) | <0.0001 | ||||||
| <5 (1357, 44.8) | 693 (34.5) | 664 (65.2) | -64.44 | 276 (34.5) | 528 (66.1) | -66.47 | |
| ≥5 (1671, 55.2) | 1316 (65.5) | 355 (34.8) | 64.44 | 523 (65.5) | 271 (33.9) | 66.47 | |
| Tumor subsite | <0.0001 | ||||||
| Lip (99, 3.3) | 74 (3.7) | 25 (2.5) | 7.14 | 20 (2.5) | 21 (2.6) | -0.79 | |
| Tongue (1272, 42.0) | 775 (38.6) | 497 (48.8) | -20.67 | 368 (46.1) | 371 (46.4) | -0.75 | |
| Gum (386, 12.7) | 267 (13.3) | 119 (11.7) | 4.88 | 87 (10.9) | 92 (11.5) | -1.98 | |
| Mouth floor (129, 4.3) | 91 (4.5) | 38 (3.7) | 4.02 | 36 (4.5) | 35 (4.4) | 0.61 | |
| Hard palate (48, 1.6) | 24 (1.2) | 24 (2.4) | -8.8 | 16 (2.0) | 15 (1.9) | 0.97 | |
| Buccal (888, 29.3) | 625 (31.1) | 263 (25.8) | 11.77 | 231 (28.9) | 218 (27.3) | 3.62 | |
| Retromolar (140, 4.6) | 104 (5.2) | 36 (3.5) | 8.06 | 27 (3.4) | 31 (3.9) | -2.68 | |
| Other sites (66, 2.2) | 49 (2.4) | 17 (1.6) | 5.44 | 14 (1.7) | 16 (2.0) | -1.84 | |
| Sex | <0.0001 | ||||||
| Men (2703, 89.3) | 1843 (91.7) | 860 (84.4) | 22.79 | 702 (87.9) | 705 (88.2) | -1.16 | |
| Women (325, 10.7) | 166 (8.3) | 159 (15.6) | -22.79 | 97 (12.1) | 94 (11.8) | 1.16 | |
| Age (years) | 0.0003 | ||||||
| <65 (2511, 82.9) | 1701 (84.7) | 810 (79.5) | 13.54 | 646 (80.9) | 662 (82.9) | -5.2 | |
| ≥65 (517, 17.1) | 308 (15.3) | 209 (20.5) | -13.54 | 153 (19.1) | 137 (17.1) | 5.2 | |
| Pathologic T status | <0.0001 | ||||||
| T1 (587, 19.4) | 328 (16.3) | 259 (25.4) | -22.51 | 189 (23.7) | 180 (22.5) | 2.67 | |
| T2 (962, 31.8) | 620 (30.9) | 342 (33.6) | -5.78 | 252 (31.5) | 262 (32.8) | -2.68 | |
| T3 (468, 15.5) | 313 (15.6) | 155 (15.2) | 1.02 | 137 (17.1) | 129 (16.1) | 2.69 | |
| T4 (1011, 33.4) | 748 (37.2) | 263 (25.8) | 24.77 | 221 (27.7) | 228 (28.6) | -1.95 | |
| Pathologic N status | 0.0009 | ||||||
| pN0 (1988, 65.7) | 1301 (64.8) | 687 (67.4) | -5.62 | 546 (68.3) | 535 (67.0) | 2.94 | |
| pN1 (309, 10.2) | 194 (9.7) | 115 (11.3) | -5.32 | 93 (11.6) | 88 (11.0) | 1.97 | |
| pN2 (272, 9.0) | 173 (8.6) | 99 (9.7) | -3.83 | 64 (8.0) | 75 (9.4) | -4.89 | |
| pN3 (459, 15.2) | 341 (16.9) | 118 (11.6) | 15.46 | 96 (12.1) | 101 (12.6) | -1.9 | |
| Pathologic stage | <0.0001 | ||||||
| I (518, 17.1) | 291 (14.5) | 227 (22.3) | -20.22 | 166 (20.8) | 159 (19.9) | 2.18 | |
| II (705, 23.3) | 464 (23.1) | 241 (23.7) | -1.31 | 179 (22.4) | 187 (23.4) | -2.38 | |
| III (465, 15.4) | 302 (15.0) | 163 (16.0) | -2.66 | 148 (18.5) | 130 (16.3) | 5.95 | |
| IV (1340, 44.3) | 952 (47.4) | 388 (38.0) | 18.9 | 306 (38.3) | 323 (40.4) | -4.36 | |
| Tumor differentiation | <0.0001 | ||||||
| Well (812, 26.8) | 375 (18.7) | 437 (42.9) | -54.38 | 286 (35.8) | 296 (37.0) | -2.6 | |
| Moderately (1902, 62.8) | 1359 (67.6) | 543 (53.3) | 29.69 | 473 (59.2) | 465 (58.2) | 2.03 | |
| Poorly (314, 10.4) | 275 (13.7) | 39 (3.8) | 35.43 | 40 (5.0) | 38 (4.8) | 1.16 | |
| Depth of invasion (mm) | <0.0001 | ||||||
| <10 (1554, 51.3) | 971 (48.3) | 583 (57.2) | -17.86 | 444 (55.6) | 436 (54.6) | 2.01 | |
| ≥10 (1474, 48.7) | 1038 (51.7) | 436 (42.8) | 17.86 | 355 (44.4) | 363 (45.4) | -2.01 | |
| Extra-nodal extension | 0.0006 | ||||||
| No (2564, 84.7) | 1669 (83.1) | 895 (87.8) | -13.52 | 706 (88.4) | 700 (87.6) | 2.31 | |
| Yes (464, 15.3) | 340 (16.9) | 124 (12.2) | 13.52 | 93 (11.6) | 99 (12.4) | -2.31 | |
| Neck nodal yield | <0.0001 | ||||||
| <15 nodes (228, 7.5) | 35 (1.7) | 193 (18.9) | -58.88 | 35 (4.4) | 30 (3.8) | 3.17 | |
| ≥15 nodes (2800, 92.5) | 1974 (98.3) | 826 (81.1) | 58.88 | 764 (95.6) | 769 (96.2) | -3.17 | |
| Treatment modality | 0.0075 | ||||||
| S alone (1540, 50.9) | 987 (49.1) | 553 (54.3) | -10.3 | 466 (58.3) | 444 (55.6) | 5.56 | |
| S plus adjuvant therapyb
(1488, 49.1) |
1022 (50.9) | 466 (45.7) | 10.3 | 333 (41.7) | 355 (44.4) | -5.56 | |
PS, propensity score; S, surgery; CT, chemotherapy; RT, radiotherapy; SMD, standardized mean difference.
aChi-square test; bS plus CT + S plus RT+ S plus CT and RT.