Table 1 Baseline characteristics and pathology of patients with uncommon EGFR mutations
Characteristics | Total (n = 28) | EGFR-TKI (n = 16) | Chemotherapy alone (n = 8) | Best supportive care (n = 4) |
|---|---|---|---|---|
Age (years), median (range) | 68 (53–80) | 67.5 (53–80) | 67.5 (54–75) | 75 (68–79) |
Gender, n (%) | ||||
 Female | 10 (35.7) | 4 (14.2) | 4 (14.2) | 2 (7.1) |
 Male | 18 (64.2) | 12 (42.8) | 4 (14.2) | 2 (7.1) |
ECOG | ||||
 - 0–1 | 23 (82.1) | 15 (53.5) | 7 (25.0) | 1 (3.5) |
 - 2 | 2 (7.1) | 0 (0) | 1 (3.5) | 1 (3.5) |
 - 3 | 3 (10.7) | 1 (3.5) | 0 (0) | 2 (7.1) |
Stage at diagnosis | ||||
 I | 1 (3.5) | 0 (0) | 1 | 0 (0) |
 II | 0 (3.5) | 0 (0) | 0 (0) | 0 (0) |
 IIIA | 1 (3.5) | 0(0) | 0 (0) | 1 (3.5) |
 IIIB | 2 (7.1) | 2 (7.1) | 0 (0) | 0 (0) |
 IV | 24 (85.7) | 14 (50) | 7 (25) | 3 (10.7) |
Specimen/site biopsy, n (%) | ||||
 Lung parenchyma | 11 (39.2) | 7 (25) | 3 (10.7) | 1 (3.5) |
 Pleural nodule | 6 (21.4) | 3 (10.7) | 2 (7.1) | 1 (3.5) |
 Lymph node | 1 (3.5) | 1 (3.5) | 0 (0) | 0 (0) |
 Bone | 1 (3.5) | 1 (3.5) | 0 (0) | 0 (0) |
 Other | 1 (3.5) | 1 (3.5) | 0 (0) | 0 (0) |
 Cytology | 3 (10.7) | 2 (7.1) | 1 (3.5) | 0 (0) |
 Plasma only | 5 (17.8) | 2 (7.1) | 2 (7.1) | 1 (3.5) |
Smoking status, n (%) | ||||
 Never smoked | 14 (50) | 8 (28.5) | 4 (14.2) | 2 (7.1) |
 Ex-smoker/smoker | 14 (50) | 8 (28.5) | 4 (14.2) | 2 (7.1) |
Histology, n (%) | ||||
 Adenocarcinoma | 27 (96.4) | 15 (53.5) | 8 (28.5) | 4 (14.2) |
 Squamous cell | 1 (3.5) | 1 (3.5) | 0 (0) | 0 (0) |
 Extra- pulmonary metastasis, n (%) | 18 (64.2) | 10 (35.7) | 7 (25) | 1 (3.5) |
 Present of CNS metastasis, n (%) | 5 (17.8) | 1 (3.5) | 4 (14.2) | 0 (0) |
Mutation subtypes, n (%) | ||||
 Single mutation | ||||
  Exon 20 insertion | 6 (21.4) | 0 (0) | 5 (17.8) | 1 (3.5) |
  Exon 21 L861Q | 5 (17) | 4 (14.2) | 1 (3.5) | 0 (0) |
  Exon 18 G719X | 4 (14.2) | 3 (10.7) | 0 (0) | 1 (3.5) |
 Compound mutation | ||||
  G719X+ Exon 20 S768I | 4 (14.2) | 2 (7.1) | 0 (0) | 2 (7.1) |
  De novo T790 M + L858R | 1 (3.5) | 0 (0) | 1 (3.5) | 0 (0) |
  De novo T790 M + del19 | 3 (10.7) | 3 (10.7) | 0 (0) | 0 (0) |
  L858R + del19 | 2 (7.1) | 2 (7.1) | 0 (0) | 0 (0) |
  L858R + Ex20Ins | 1 (3.5) | 0 (0) | 1 (3.5) | 0 (0) |
  Del19 + KRAS | 1 (3.5) | 1 (3.5) | 0 (0) | 0 (0) |
  G719X + E709A | 1 (3.5) | 1 (3.5) | 0 (0) | 0 (0) |
EGFR-TKI, n (%) | ||||
 Erlotinib | 8 (28.5) |  |  |  |
 Gefitinib | 6 (21.4) |  |  |  |
 Afatinib | 2 (7.1) |  |  |  |
Line of TKI treatment, n (%) | ||||
 First-line | 7 (25) |  |  |  |
 Second-line | 7 (25) |  |  |  |
 Third-line or later | 2 (7.1) |  |  |  |
Subsequent osimertinib, n (%) | ||||
 Del19 + L858R with acquire T790 M | 1 (3.5) |  |  |  |
 De novo T790 M + del19 | 2 (7.1) |  |  |  |