Table 3.
Investigations for Resistance Mechanisms in Patients with Acquired EGFR Exon 20 T790M Mutation
| Resistance Mechanism Investigation | All Patients (n = 87) | Patients with T790M (n = 55) | p value* |
|---|---|---|---|
| Type of biopsy, No. (%) | |||
| Liquid biopsy | 35 | 20 (57.1) | 0.205 |
| Tissue re-biopsy | 35 | 26 (74.3) | |
| Liquid followed by tissue re-biopsy | 17 | 9 (52.9) | |
| Type of liquid biopsy | All patients (n = 52) | Patients with T790M (n = 29) | p value* |
| Liquid biopsy platform, No. (%) | |||
| PNA-LNA PCR | 28 | 15 (53.6) | 0.730 |
| ddPCR | 24 | 14 (58.3) | |
| Tissue re-biopsy | All patients (n = 52) | Patients with T790M (n = 35) | p value* |
| Site of re-biopsy, No. (%) | |||
| Lung primary | 28 | 17 (60.7) | 0.323 |
| Lung metastasis | 11 | 9 (81.8) | |
| Brain metastasis | 1 | 0 | |
| Liver metastasis | 10 | 8 (80.0) | |
| Lymph node metastasis | 2 | 1 (50.0) |
Note: *Chi-square for categorical variables.
Abbreviations: PNA-LNA PCR, peptic nucleic acid-locked nucleic acid polymerase chain reaction; ddPCR, droplet digital polymerase chain reaction.