TABLE 1.
Clinicopathological characteristics of the patients
| n = 21 | |
|---|---|
| Age | 73 ± 7.2 (56–87) |
| Sex | |
| Male | 7 |
| Female | 14 |
| Smoking status | |
| Non‐smoker | 14 |
| Smoker | 6 |
| Unknown | 1 |
| Brinkman Index | 195.8 ± 403 |
| Histology | |
| Adenocarcinoma | 21 |
| EGFR mutation | |
| Exon 19 deletion | 9 |
| L858R | 12 |
| T790M (before EGFR‐TKI resistance acquirement) | 0 |
| T790M (after EGFR‐TKI resistance acquirement) | 5* |
Data are presented as mean ± SD. Brinkman Index was calculated by the number of cigarettes smoked per day multiplied by the number of years of smoking history of individuals.
Abbreviations: EGFR, epidermal growth factor receptor; EGFR‐TKI, EGFR tyrosine kinase inhibitor.
*
We could only evaluate the status of EGFR mutation in 10 of 21 specimens after EGFR‐TKI resistance acquirement.