TABLE 1.
Characteristics of patients in the primary and validation cohorts
| Variable | Primary cohort (n = 330) | Validation cohort (n = 101) | ||||
|---|---|---|---|---|---|---|
| LN− (n = 255) | LN+ (n = 75) | p‐value | LN− (n = 70) | LN+ (n = 31) | p‐value | |
| Gender | 0.573 | 0.668 | ||||
| Male | 182 (71.4%) | 51 (68.0%) | 46 (65.7%) | 19 (61.3%) | ||
| Female | 73 (28.6%) | 24 (32.0%) | 24 (34.3%) | 12 (38.7%) | ||
| Age | 0.225 | 0.013 | ||||
| 62.5 (10.8) | 61.3 (9.5) | 62.7 (8.8) | 58.5 (9.0) | |||
| Tumor SUVmax | <0.001 | 0.003 | ||||
| 7.1 (5.1) | 11.6 (8.1) | 7.8 (6.2) | 11.0 (4.1) | |||
| Tumor volume | 0.004 | 0.001 | ||||
| 11.2 (11.4) | 18.2 (19.4) | 16.2 (19.8) | 37.6 (33.4) | |||
| Tumor location | <0.001 | 0.006 | ||||
| Peripheral | 153 (60.0%) | 25 (33.3%) | 41 (58.6%) | 9 (29.0%) | ||
| Central | 102 (40.0%) | 50 (66.7%) | 29 (41.4%) | 22 (71.0%) | ||
| LN SUVmax | <0.001 | <0.001 | ||||
| 2.2 (1.5) | 4.8 (3.7) | 2.1 (1.7) | 4.9 (4.4) | |||
| LN SUVave | <0.001 | <0.001 | ||||
| 1.7 (0.8) | 3.2 (2.2) | 1.8 (1.1) | 3.2 (2.7) | |||
| LN short axis (mm) | <0.001 | 0.004 | ||||
| 5.8 (1.8) | 7.7 (2.9) | 5.1 (1.6) | 7.1 (3.4) | |||
| SURmax‐Lea | <0.001 | <0.001 | ||||
| 1.3 (1.0) | 3.3 (2.7) | 1.2 (1.1) | 3.2 (2.9) | |||
| SURmax‐Ivc | <0.001 | <0.001 | ||||
| 1.4 (1.2) | 3.3 (2.7) | 1.5 (1.6) | 3.8 (3.7) | |||
| SURmax‐Liv | <0.001 | <0.001 | ||||
| 0.8 (0.6) | 1.8 (1.4) | 0.7 (0.6) | 1.8 (1.8) | |||
| SURmax‐Ara | <0.001 | <0.001 | ||||
| 1.4 (1.1) | 3.2 (2.6) | 1.4 (1.4) | 3.3 (2.9) | |||
| Cell type | 0.230 | 0.297 | ||||
| Adenocarcinoma | 153 (60.0%) | 47 (62.7%) | 35 (50.0%) | 13 (41.9%) | ||
| Squamous cell carcinoma | 72 (28.2%) | 15 (20.0%) | 29 (41.4%) | 12 (38.7%) | ||
| Other | 30 (11.8%) | 13 (17.3%) | 6 (8.6%) | 6 (19.4%) | ||
| Smoking status | 0.686 | 0.489 | ||||
| Current | 83 (32.5%) | 27 (36.0%) | 17 (24.3%) | 5 (16.1%) | ||
| Former | 59 (23.1%) | 19 (25.3%) | 12 (17.1%) | 4 (12.9%) | ||
| Never | 113 (44.3%) | 29 (38.7%) | 41 (58.6%) | 22 (71.0%) | ||
| Suspicious LN metastasis | 0.013 | 0.017 | ||||
| <2 stations | 92 (36.1%) | 39 (52.0%) | 23 (32.9%) | 18 (58.1%) | ||
| >=2 stations | 163 (63.9%) | 36 (48.0%) | 47 (67.1%) | 13 (41.9%) | ||
Note: The p‐value is derived from the univariable association analyses between each of the clinicopathological variables and LN status.
Abbreviations: LN, lymph node; LN−, lymph node negative; LN+, lymph node metastasis; mm, millimeter; SUVave, average standardized uptake value; SUVmax, maximum standardized uptake value.