Table 1.
Demographic, clinical and pathologic characteristics of the included patients.
| Derivation cohort (n = 1,008) |
Validation cohort (n = 1,058) |
Entire cohort (n = 2,066) |
|
|---|---|---|---|
| Age, year | 64.3 ± 11.2 | 63.0 ± 11.2 | 63.6 ± 11.2 |
| Sex, male | 525 (52.1%) | 530 (50.1%) | 1055 (51.1%) |
| Body mass index, kg·m-2 | 24.0 ± 3.5 | 24.1 ± 3.5 | 24.0 ± 3.5 |
| Cigarette smoking | 284 (28.2%) | 269 (25.4%) | 553 (26.8%) |
| ASA class ≥ 3 | 264 (26.2%) | 243 (23.0%) | 507 (24.5%) |
| ECOG grade ≥ 1 | 345 (34.2%) | 298 (28.2%) | 643 (31.1%) |
| Comorbidities | |||
| Chronic obstructive pulmonary disease | 111 (11.0%) | 97 (9.2%) | 208 (10.1%) |
| Diabetes | 173 (17.2%) | 161 (15.2%) | 334 (16.2%) |
| Coronary artery disease | 105 (10.4%) | 97 (9.2%) | 202 (9.8%) |
| Heart failure | 51 (5.1%) | 35 (3.3%) | 86 (4.2%) |
| Stroke | 38 (3.8%) | 35 (3.3%) | 73 (3.5%) |
| Chronic kidney disease | 83 (8.2%) | 84 (7.9%) | 167 (8.1%) |
| Preoperative pulmonary function | |||
| FVC, % predicted | 87.1 ± 15.8 | 87.5 ± 15.4 | 87.3 ± 15.6 |
| FEV1, % predicted | 85.7 ± 16.4 | 86.1 ± 16.4 | 85.9 ± 16.4 |
| Preoperative carcinoembryonic antigen, μg·L-1* | 2.4 (1.8–3.9) | 2.3 (1.7–3.7) | 2.4 (1.8–3.8) |
| Preoperative hemoglobin concentration, g·dL-1 | 13.0 ± 1.5 | 13.1 ± 1.4 | 13.1 ± 1.5 |
| Surgical and anesthetic variables | |||
| Type of surgery | |||
| Sublobar resection or lobectomy | 769 (76.5%) | 799 (75.7%) | 1568 (76.1%) |
| Bilobectomy or pneumonectomy | 236 (23.5%) | 257 (24.3%) | 493 (23.9%) |
| Thoracoscopic surgery | 642 (63.7%) | 786 (74.3%) | 1428 (69.1%) |
| Radical lymph node dissection | 902 (89.7%) | 797 (75.4%) | 1699 (82.4%) |
| Intraoperative blood loss, mL | 100 (50–200) | 50 (30–150) | 100 (30 200) |
| Blood transfusion | 168 (16.7%) | 91 (8.6%) | 259 (12.5%) |
| Epidural analgesia | 838 (83.1%) | 864 (81.7%) | 1702 (82.4%) |
| Anesthesia time, min | 315 (270–375) | 300 (240–360) | 300 (255–360) |
| Inflammation biomarkers | |||
| Prognostic nutritional index | 50.2 (46.9–53.4) | 49.5 (45.6–52.9) | 49.8 (46.3–53.1) |
| Preoperative NLR | 2.0 (1.4–2.7) | 1.9 (1.4–2.6) | 1.9 (1.4–2.7) |
| Postoperative NLR | 12.4 (8.7–17.9) | 11.9 (8.8–17.9) | 12.2 (8.7–17.9) |
| Absolute change of NLR | 10.2 (6.5–15.4) | 9.8 (6.6–15.3) | 10.0 (6.6–15.3) |
| Relative change of NLR, % | 525 (308–822) | 517 (302–814) | 521 (305–817) |
| Preoperative PLR | 123.7 (94.6–164.9) | 121.5 (95.7–156.1) | 122.6 (95.0–162.1) |
| Postoperative PLR | 227.7 (162.3–323.5) | 223.6 (160.9–314.6) | 225.2 (161.9–320.2) |
| Absolute change of PLR | 97.4 (40.6–178.0) | 92.3 (42.9–170.0) | 96.1 (41.9–177.3) |
| Relative change of PLR, % | 79 (36–148) | 82 (33–145) | 81 (36–146) |
| Absolute change of lymphocyte count, 103·μL−1 | − 863 (− 1225 to − 515) | − 1223 (− 1751 to − 729) | − 1019 (− 1496 to − 608) |
| Pathologic features | |||
| Cancer stage | |||
| I | 708 (70.2%) | 789 (74.6%) | 1497 (72.5%) |
| II | 135 (13.4%) | 114 (10.8%) | 249 (12.1%) |
| III | 165 (16.4%) | 155 (14.7%) | 320 (15.5%) |
| Subtype | |||
| Adenocarcinoma | 821 (81.5%) | 895 (84.6%) | 1716 (83.1%) |
| Squamous cell carcinoma | 130 (12.9%) | 113 (10.7%) | 243 (11.8%) |
| Others | 57 (5.7%) | 50 (4.7%) | 107 (5.2%) |
| Tumor differentiation | |||
| Good | 73 (7.3%) | 132 (12.5%) | 205 (9.9%) |
| Moderate | 610 (60.6%) | 630 (59.6%) | 1240 (60.1%) |
| Poor | 324 (32.2%) | 295 (27.9%) | 619 (30.0%) |
| Microscopic necrosis | 248 (24.6%) | 202 (19.1%) | 450 (21.8%) |
| Lymphocytic infiltration | 113 (11.2%) | 96 (9.1%) | 209 (10.1%) |
| Lymphovascular invasion | 306 (30.4%) | 292 (27.6%) | 598 (28.9%) |
| Perineural infiltration | 36 (3.6%) | 32 (3.0%) | 68 (3.3%) |
| Preoperative chemotherapy ± radiotherapy | 51 (5.1%) | 45 (4.3%) | 96 (4.7%) |
| Postoperative chemotherapy | 483 (47.9%) | 463 (43.8%) | 946 (45.8%) |
| Postoperative radiotherapy | 63 (6.3%) | 51 (4.8%) | 114 (5.5%) |
| Year of operation | |||
| 2005–2010 | 500 (49.6%) | 365 (34.5%) | 865 (41.9%) |
| 2011–2015 | 508 (50.4%) | 693 (65.5%) | 1201 (58.1%) |
Values are mean ± SD, count (percent), or median (interquartile range).
ASA, American Society of Anesthesiologists; ECOG, Eastern Cooperative Oncology Group; FEV1, forced expiratory volume in one second; FVC, forced vital capacity; NLR, neutrophil-to-lymphocyte ratio; PLR, platelet-to-lymphocyte ratio.