Table 1

Patient characteristics

CharacteristicDiscovery (n=536)Validation (n=405)P value
Mean age (SD), years65.4 (10.4)67.0 (9.4) 0.02
Gender0.36
 Male246 (45.9)198 (48.9)
 Female290 (54.1)207 (51.1)
Mean no of smoking pack years, (SD)54.2 (34.1)53.3 (33.6)0.72
Smoking status 3.89E-12
 Never108 (20.1)17 (4.2)
 Former243 (45.3)237 (58.5)
 Current185 (34.5)151 (37.3)
Tumor stage*0.6
 I358 (66.8)277 (68.4)
 II178 (33.2)128 (31.6)
Tumor grade0.13
 Well differentiated54 (10.1)45 (11.1)
 Moderately differentiated202 (37.7)133 (32.8)
 Poorly differentiated195 (36.4)160 (39.5)
 Undifferentiated13 (2.4)3 (0.7)
 Unknown72 (13.4)64 (15.8)
ECOG score2.60E-07
 0106 (19.8)100 (24.7)
 1127 (23.7)146 (36.0)
 225 (4.7)24 (5.9)
 No record278 (51.9)135 (33.3)
Histology
 Adenocarcinoma314 (58.6)228 (56.3)0.08
 Squamous cell carcinoma137 (25.6)127 (31.4)
 Other‡85 (15.9)50 (12.4)
Treatment 4.00E-04
 No surgery†74 (13.8)94 (23.2)
 Surgery only311 (58.0)208 (51.4)
 Surgery plus chemotherapy132 (24.6)98 (24.2)
 Surgery plus radiation19 (3.6)5 (1.2)
Recurrence0.4
 No339 (63.2)267 (65.9)
 Yes197 (36.8)138 (34.1)
Vital status 1.30E-15
 Living306 (57.1)280 (69.1)
 Deceased230 (42.9)125 (30.9)
  • All data are number of patients (%) unless otherwise indicated.

  • Significant p values in bold font.

  • *Tumor stage was determined according to American Joint Committee onCancer v.7.0.

  • †For patients without surgery but with chemotherapy, radiation or chemoradiation treatment.

  • ‡Others refer to adenosquamous carcinoma, bonchioalveolar carcinoma and large-cell carcinoma.

  • ECOG, Eastern Cooperative Oncology Group; SD, standard deviation.