Table 1.

Characteristics of the patients, according to EGFR status

Training cohortValidation cohort
CharacteristicEGFR wt (n = 125) (%)EGFR mut (n = 193) (%)P valueaEGFR mut (n = 64) (%)
Median age (range)62 (29–82)66 (29–86)0.00361 (21–87)
Gender<0.001
 Male93 (74.4)47 (24.4)22 (34.4)
 Female32 (25.6)146 (75.6)42 (65.6)
Smoking status<0.001
 Never smokers17 (14.3)141 (73.1)29 (72.5)
 Current and former smokers102 (85.7)52 (26.9)11 (27.5)
 Unknown6024
Histology
 Squamous34 (27.2)1 (0.5)<0.001b2 (3.1)
 Nonsquamous91 (72.8)192 (99.5)62 (96.9)
  Large cell16 (12.8)3 (1.6)0 (0)
  Adenocarcinoma68 (54.4)177 (91.7)59 (92.2)
  Undifferentiated6 (4.8)6 (3.1)1 (1.6)
  Others1 (0.8)6 (3.1)2 (3.1)
Stage0.67
 IIIB11 (8.8)14 (7.3)5 (7.8)
 IV114 (91.2)179 (92.7)59 (92.2)
ECOG PS0.004
 018 (15.3)57 (29.8)9 (15.8)
 ≥1100 (84.7)134 (70.2)48 (84.2)
 Unknown727
Brain metastases0.47
 Yes16 (13.8)21 (10.9)21 (35.0)
 No100 (86.2)172 (89.1)39 (65.0)
 Unknown904
Bone metastases0.09
 Yes40 (34.5)48 (24.9)26 (41.3)
 No76 (65.5)145 (75.1)37 (58.7)
 Unknown901
Response0.17
 CR6 (5.4)10 (6.0)8 (13.1)
 PR45 (40.2)90 (53.9)36 (59.0)
 SD44 (39.3)50 (29.9)16 (26.2)
 PD17 (15.2)17 (10.2)1 (1.6)
 NE13263
 Responders (CR+PR)51 (45.5)100 (59.9)0.0244 (72.1)
 Non responders (SD+PD)61 (54.5)67 (40.1)17 (27.9)
TP53 mutated vs. wt0.13
 P53 mutated (D+NoD)43 (34.4)50 (25.9)17 (26.6)
 wt82 (56.6)143 (74.1)47 (73.4)
KRAS status (wt vs. mutated)<0.001
 wt94 (75.2)144 (99.3)NA
 Mutated31 (24.8)1 (0.7)
 Not determined048
KRAS mutation<0.001
 wt94 (75.2)144 (99.3)NA
 G12C15 (12.0)1 (0.7)
 Other mutations16 (12.8)0 (0.0)

NOTE: KRAS mutations were not determined in the validation cohort, composed entirely of EGFR-mut patients.

Abbreviations: CR, complete response; D, disruptive; ECOG PS, Eastern Cooperative Oncology Group Performance Status; NA, not analyzed; NE, not evaluable; NoD, nondisruptive; PD, progressive disease; PR, partial response; SD, stable disease.

  • aP values calculated excluding the “unknown” or “not determined” samples.

  • bP value calculated for squamous versus nonsquamous.