Table 1.
Baseline patient characteristics.
| N = 68 (%) | |
|---|---|
| Median age in years (range) | 66 (47–87) |
| Sex | |
| Male | 14 (20.6) |
| Female | 54 (79.4) |
| Histology | |
| Adenocarcinoma | 67 (98.5) |
| Squamous cell carcinoma | 1 (1.5) |
| Smoking history | |
| Never smoker | 58 (85.3) |
| Chronic smoker | 2 (2.9) |
| Ex-smoker | 8 (11.8) |
| ECOG PS | |
| 0 | 20 (29.4) |
| 1 | 48 (70.6) |
| Site of metastases before TKI therapy | |
| Lung | 59 (86.8) |
| Pleura/pleural effusion | 30 (44.1) |
| Brain | 15 (22.1) |
| Liver | 11 (16.2) |
| Bone | 34 (50.0) |
| Distant lymph nodes | 18 (26.5) |
| Number of sites of metastases before 1st line TKI therapy | |
| 1 | 15 (22.1) |
| 2 | 12 (32.4) |
| 3 | 19 (27.9) |
| 4 | 9 (13.2) |
| 5 | 3 (4.4) |
| Types of pre-treatment EGFR mutation | |
| Exon 19 mutations | 37 (54.4) |
| LRE deletions | 34 (50.0) |
| E746_A750 deletions | 31 (45.6) |
| Non-E746_A750 deletions | 3 (4.4) |
| Non-LRE deletions | 3 (4.4) |
| Exon 21 L858R mutations | 31 (45.6) |
| Double mutations | 3 (4.4) |
| Exon 19 deletion + exon 20 D807E mutation | 1 (1.5) |
| Exon 21 L858R mutation + exon V765L mutation | 1 (1.5) |
| Exon 21 L858R mutation + exon 18 G719A mutation | 1 (1.5) |
| Number of lines of TKI therapies before liquid biopsy | |
| 1 TKI | 53 (77.9) |
| 2 TKIs | 12 (17.6) |
| 3 TKIs | 3 (4.4) |
| First-line TKI used | 68 (100) |
| Gefitinib | 54 (79.4) |
| Erlotinib | 7 (10.3) |
| Afatinib | 7 (10.3) |
| Second-line TKI used | 14 (20.6) |
| Gefitinib | 2 (2.9) |
| Erlotinib | 8 (11.8) |
| Afatinib | 4 (5.9) |
| Third-line TKI used | 3 (4.4) |
| Gefitinib | 0 (0) |
| Erlotinib | 2 (2.9) |
| Afatinib | 1 (1.5) |
| Best overall response after 1st (n = 68)/2nd (n = 14)/3rd (n = 3) TKI therapy before liquid biopsy | |
| Complete response | 5 (7.4)/0 (0)/0 (0) |
| Partial response | 39 (57.4)/2 (2.9)/0 (0) |
| Stable disease | 21 (30.9)/6 (8.8)/2 (2.9) |
| Progressive disease | 3 (4.4)/6 (8.8)/1 (1.5) |
| Number of lines of prior chemotherapy ± anti-VEGF therapy before liquid biopsy | |
| 0 line | 44 (64.7) |
| 1 line | 16 (23.5) |
| 2 lines | 6 (8.8) |
| 3 lines | 2 (2.9) |
| Best overall response after 1st (n = 23)/2nd (n = 9)/3rd (n = 2) line chemotherapy ± anti-VEGF therapy before liquid biopsy | |
| Complete response | 1 (1.5)/0 (0)/0 (0) |
| Partial response | 7 (10.3)/4 (5.9)/(1 (1.5) |
| Stable disease | 7 (10.3)/3 (4.4)/0 (0) |
| Progressive disease | 8 (11.8)/2 (2.9)/1 (1.5) |
ECOG: Eastern Cooperative Oncology Group; EGFR: epidermal growth factor receptor; PD: progressive disease; PS: performance status; TKI: tyrosine-kinase inhibitors; VEGF: vascular endothelial growth factor.