Table 1.
Comparison of Baseline Characteristics Between the Training and Validation Datasets
| Variable | Total (N=460) | Training Set (N=296) | Validation Set (N=164) | P-value |
|---|---|---|---|---|
| Age (year), median [IQR] | 46 [39–54] | 46 [39–55] | 46 [40–53] | 0.859 |
| Sex | 1.000 | |||
| Female | 69 (15.0) | 44 (14.9) | 25 (15.2) | |
| Male | 391 (85.0) | 252 (85.1) | 139 (84.8) | |
| Comorbidity | 0.566 | |||
| Absent | 322 (70.0) | 204 (68.9) | 118 (72.0) | |
| Present | 138 (30.0) | 92 (31.1) | 46 (28.0) | |
| BMI (kg/m2), median [IQR] | 20.8 [18.7–23.4] | 20.8 [18.7–23.2] | 21.1 [19.0–23.9] | 0.370 |
| Histology | 0.645 | |||
| Type II | 18 (3.91) | 13 (4.39) | 5 (3.05) | |
| Type III | 442 (96.1) | 283 (95.6) | 159 (97.0) | |
| T category | 0.262 | |||
| T1–2 | 84 (18.3) | 59 (19.9) | 25 (15.2) | |
| T3–4 | 376 (81.7) | 237 (80.1) | 139 (84.8) | |
| N category | 0.170 | |||
| N0–1 | 87 (18.9) | 62 (20.9) | 25 (15.2) | |
| N2–3 | 373 (81.1) | 234 (79.1) | 139 (84.8) | |
| No. of metastatic sites | 0.180 | |||
| Single | 303 (65.9) | 202 (68.2) | 101 (61.6) | |
| Multiple | 157 (34.1) | 94 (31.8) | 63 (38.4) | |
| No. of metastatic lesions | 0.827 | |||
| Single | 97 (21.1) | 61 (20.6) | 36 (22.0) | |
| Multiple | 363 (78.9) | 235 (79.4) | 128 (78.0) | |
| Liver metastasis | 0.403 | |||
| Absent | 307 (66.7) | 193 (65.2) | 114 (69.5) | |
| Present | 153 (33.3) | 103 (34.8) | 50 (30.5) | |
| Bone metastasis | 0.799 | |||
| Absent | 155 (33.7) | 98 (33.1) | 57 (34.8) | |
| Present | 305 (66.3) | 198 (66.9) | 107 (65.2) | |
| Lung metastasis | 0.655 | |||
| Absent | 327 (71.1) | 213 (72.0) | 114 (69.5) | |
| Present | 133 (28.9) | 83 (28.0) | 50 (30.5) | |
| Pretreatment EBV DNA | 0.001 | |||
| Negative | 67 (14.6) | 44 (14.9) | 23 (14.0) | |
| Positive | 356 (77.4) | 217 (73.3) | 139 (84.8) | |
| Missing | 37 (8.0) | 35 (11.8) | 2 (1.2) | |
| LDH (U/L), median [IQR] | 209 [173–298] | 207 [173–293] | 211 [174–304] | 0.417 |
| CRP (mg/L), median [IQR] | 3.93 [1.30–13.7] | 3.78 [1.16–14.9] | 4.17 [1.52–12.2] | 0.649 |
| ALP (U/L), median [IQR) | 82.0 [68.2–101] | 80.1 [67.9–99.2] | 85.4 [69.7–105] | 0.054 |
| GPS | 0.559 | |||
| 0 | 319 (69.3) | 202 (68.2) | 117 (71.3) | |
| 1–2 | 141 (30.7) | 94 (31.8) | 47 (28.7) | |
| NLR, median [IQR] | 2.70 [1.92–3.79] | 2.68 [1.88–3.75] | 2.78 [1.96–3.80] | 0.763 |
| PLR, median [IQR] | 142 [107–194] | 141 [104–193] | 143 [111–200] | 0.917 |
| SII, median [IQR] | 648 [426–1056] | 642 [416–1054] | 665 [471–1059] | 0.479 |
| PNI, median [IQR] | 52.2 [48.5–55.3] | 52.2 [48.5–55.5] | 52.3 [48.5–54.6] | 0.487 |
| NRI, median [IQR] | 107 [102–112] | 107 [101–112] | 107 [102–112] | 0.661 |
| CONUT score | 0.117 | |||
| 3–4 | 389 (84.6) | 244 (82.4) | 145 (88.4) | |
| 5–6 | 71 (15.4) | 52 (17.6) | 19 (11.6) |
Note: Statistical comparisons of patient characteristics between groups were analyzed using the Mann–Whitney U-tests (for continuous variables) or χ2 tests (for categorical variables).
Abbreviations: BMI, body mass index; EBV, Epstein-Barr virus; LDH, lactate dehydrogenase; CRP, C reactive protein; ALP, alkaline phosphatase; GPS, Glasgow prognostic score; NLR, neutrophil-lymphocyte ratio; PLR, platelet-to-lymphocyte ratio; SII, systemic immune-inflammation index; PNI, prognostic nutritional index; NRI, nutrition risk index; CONUT score, controlling nutritional status score.