| EGFR wild-type | EGFR mutant | p-value | |
| Patients n | 1788 | 604 | |
| Population characteristics | |||
| Age yrs | 65±11 | 64±12 | 0.370 |
| Sex | |||
| Males | 682 (38) | 169 (28) | <0.001 |
| Females | 1106 (62) | 435 (72) | |
| Race | |||
| White | 1688 (94) | 570 (94) | 0.970 |
| Other | 100 (6) | 34 (6) | |
| Smoking status | |||
| Never-smokers | 333 (19) | 330 (55) | <0.001 |
| Smokers | 1455 (81) | 274 (45) | |
| Total tobacco quantity pack-yrs | 40±28 | 15±17 | <0.001 |
| Former smokers | 1085 (60) | 251 (42) | |
| Time since quitting yrs | 20±14 | 27±14 | <0.001 |
| Current smokers | 370 (21) | 23 (4) | |
| Tumour characteristics | |||
| Histology | |||
| Predominant subtype | |||
| Acinar | 700 (39) | 110 (18) | <0.001 |
| Papillary | 209 (12) | 181 (30) | <0.001 |
| BAC | 312 (17) | 148 (25) | <0.001 |
| Solid | 252 (14) | 55 (9) | 0.002 |
| NOS | 315 (18) | 110 (18) | 0.741 |
| TTF-1 expression# | |||
| Yes | 764 (43) | 284 (47) | <0.001 |
| No | 149 (8) | 8 (2) | |
| Stage | |||
| I–IIIA | 984 (55) | 274 (45) | <0.001 |
| IIIB–IV | 804 (45) | 330 (55) | |
| KRAS mutational status¶ | |||
| Mutant | 330 (18) | 0 (0) | <0.001 |
| Wild-type | 1172 (66) | 507 (84) |
Data are presented as median±sd or n (%), unless otherwise stated. BAC: bronchioloalveolar carcinoma; NOS: not otherwise specified; TTF: thyroid transcription factor. #: data missing for 875 (49%) EGFR wild-type tumours and 312 (52%) EGFR mutant tumours; ¶: data missing for 286 (16%) EGFR wild-type tumours and 97 (16%) EGFR mutant tumours.