TABLE 1.
Clinical characteristics by pathological nodal stage in patients with radiological N0 nonsmall cell lung cancer (NSCLC)
| Overall | Pathological N0 or N1 | Pathological N2 or N3# | p-value¶ | Univariate OR (95% CI) | |
| Subjects | 1337 | 1244 | 93 | ||
| Age years | 61.9±9.5 | 61.9±9.5 | 61.0±10.3 | 0.366+ | 0.99 (0.97−1.01) |
| Sex | 0.824 | ||||
| Female | 633 (47.3) | 590 (47.4) | 43 (46.2) | 1.00 (reference) | |
| Male | 704 (52.7) | 654 (52.6) | 50 (53.8) | 1.05 (0.69−1.60) | |
| Smoking status | 0.310 | ||||
| Never-smoker | 693 (51.8) | 645 (51.9) | 48 (51.6) | 1.00 (reference) | |
| Ex-smoker | 438 (32.8) | 412 (33.1) | 26 (28.0) | 0.85 (0.52−1.39) | |
| Current smoker | 206 (15.4) | 187 (15.0) | 19 (20.4) | 1.36 (0.78−2.38) | |
| Size of tumour cmƒ | 2.85±1.59 | 2.79±1.55 | 3.70±1.80 | <0.001+,## | 1.32 (1.19–1.46) |
| ≤3 | 838 (62.7) | 799 (64.2) | 39 (41.9) | 1.00 (reference) | |
| >3– ≤5 | 375 (28.0) | 339 (27.3) | 36 (38.7) | 2.18 (1.36−3.48) | |
| >5 | 124 (9.3) | 106 (8.5) | 18 (19.4) | 3.48 (1.92−6.30) | |
| Lobar location | 0.176 | ||||
| Right upper | 423 (31.6) | 394 (31.7) | 29 (31.2) | 1.00 (reference) | |
| Right middle | 104 (7.8) | 98 (7.9) | 6 (6.5) | 0.83 (0.34−2.06) | |
| Right lower | 269 (20.1) | 246 (19.8) | 23 (24.7) | 1.27 (0.72−2.25) | |
| Left upper | 330 (24.7) | 315 (25.3) | 15 (16.1) | 0.65 (0.34−1.23) | |
| Left lower | 211 (15.8) | 191 (15.3) | 20 (21.5) | 1.42 (0.78−2.58) | |
| Tumour attenuation on CT | 0.001 | ||||
| Ground glass | 476 (35.6) | 451 (36.3) | 25 (26.9) | 1.00 (reference) | |
| Part solid | 376 (28.1) | 359 (28.9) | 17 (18.3) | 0.85 (0.45−1.61) | |
| Solid | 485 (36.3) | 434 (34.9) | 51 (54.8) | 2.12 (1.29−3.48) | |
| Time between PET-CT and surgery days¶¶ | 25.2±21.2 | 25.4±21.3 | 22.9±20.1 | 0.265+ | 0.99 (0.98–1.01) |
| Histology of tumour | 0.097§ | ||||
| Adenocarcinoma | 1089 (81.5) | 1010 (81.2) | 79 (85.0) | 1.00 (reference) | |
| Squamous cell carcinoma | 199 (14.9) | 191 (15.4) | 8 (8.6) | 0.54 (0.25−1.13) | |
| Large cell carcinoma | 27 (2.0) | 24 (1.9) | 3 (3.2) | 1.60 (0.47−5.42) | |
| Other NSCLC | 22 (1.6) | 19 (1.5) | 3 (3.2) | 2.02 (0.58−6.97) | |
| Dissected nodes and stations during MLND n++ | |||||
| Lymph nodes | 15.2±8.1 | 15.1±8.1 | 16.5±7.9 | 0.142+ | 1.02 (0.99–1.05) |
| Stations | 4.6±1.4 | 4.6±1.4 | 4.7±1.5 | 0.460+ | 1.06 (0.90–1.25) |
Data are presented as n, mean±sd or n (%), unless otherwise stated. CT: computed tomography; PET: positron emission tomography; MLND: mediastinal lymph node dissection; EBUS-TBNA: endobronchial ultrasound-guided transbronchial needle aspiration. #: two patients had occult metastasis to N3 nodes as well as N2 nodes; ¶: p-values are reported by the Chi-squared test except where otherwise noted (+: two-sample t-test; §: Fisher's exact test) and are not the p-values for the odds ratio reported from univariate analysis; ƒ: size of the tumour is measured in pre-operative CT scan; ##: p-values for the two-sample t-test and Chi-squared test are <0.001; ¶¶: for 10 patients who were confirmed to have N2 disease in EBUS-TBNA, the intervals between PET-CT and EBUS-TBNA were used; ++: analysis was done in 1327 patients after excluding 10 patients who were confirmed to have N2 disease in EBUS-TBNA and did not undergo MLND.