Table 2. Pathological characteristics before and after PSM.
| Parameters | Before PSM | After PSM (1:1) | |||||
|---|---|---|---|---|---|---|---|
| LNM− (N=1,032) | LNM+ (N=256) | P value | LNM− (N=244) | LNM+ (N=244) | P value | ||
| Tumor size (cm) | |||||||
| <2 | 400 (38.8) | 60 (23.4) | <0.001 | 52 (21.3) | 60 (24.6) | NS | |
| ≥2 | 632 (61.2) | 196 (76.6) | 192 (78.7) | 184 (75.4) | |||
| Proximal resection margin (cm) | 12.2±5.97 | 12.4±4.33 | NS | 12.9±8.17 | 12.4±4.37 | NS | |
| Distal resection margin (cm) | 6.53±3.98 | 6.09±4.12 | NS | 6.24±4.04 | 6.17±4.17 | NS | |
| Gross type | |||||||
| Protruding | 658 (63.8) | 115 (44.9) | <0.001 | 118 (48.4) | 113 (46.3) | NS | |
| Infiltrate or ulcerative | 374 (36.2) | 141 (55.1) | 126 (51.6) | 131 (53.7) | |||
| Histology type | |||||||
| Well | 559 (54.2) | 88 (34.4) | <0.001 | 91 (37.3) | 87 (35.7) | NS | |
| Mod, Por, Sig, Muc | 473 (45.8) | 168 (65.6) | 153 (62.7) | 157 (64.3) | |||
| Infiltration form | |||||||
| A | 195 (18.9) | 23 (9.0) | <0.001 | 30 (12.3) | 20 (8.2) | NS | |
| B and C | 837 (81.1) | 233 (91.0) | 214 (87.7) | 224 (91.8) | |||
| Missing | |||||||
| Lymphatic invasion | |||||||
| No | 832 (80.6) | 142 (55.5) | <0.001 | 147 (60.2) | 142 (58.2) | NS | |
| Yes | 200 (19.4) | 114 (44.5) | 97 (39.8) | 102 (41.8) | |||
| Vascular invasion | |||||||
| No | 670 (64.9) | 105 (41.0) | <0.001 | 102 (41.8) | 104 (42.6) | NS | |
| Yes | 362 (35.1) | 151 (59.0) | 142 (58.2) | 140 (57.4) | |||
| Harvested lymph nodes | 21.7±12.3 | 23.6±12.2 | 0.02 | 22.6±15.2 | 23.5±12.2 | NS | |
| pT | |||||||
| 1 | 592 (57.4) | 85 (33.2) | <0.001 | 97 (39.8) | 84 (34.4) | NS | |
| 2 | 440 (42.6) | 171 (66.8) | 147 (60.2) | 160 (65.6) | |||
Data are presented as mean ± standard deviation or n (%). Protruding: type 0, superficial; type 1, protuberant, infiltrative or ulcerative; type 2, expansive ulceration; type 3, infiltrative ulcerating; type 4, diffusely ulcerating. LNM, lymph node metastasis; LNM−, lymph node metastasis negative; LNM+, lymph node metastasis positive; Mod, moderately differentiated adenocarcinoma; Muc, mucinous carcinoma; NS, not significant; Poor, poorly differentiated adenocarcinoma; pT, pathological T stage; PSM, propensity score matching; Sig, signet ring carcinoma; Well, well-differentiated adenocarcinoma.