1.
患者临床特点（n=140）
Patient characteristics (n=140)
| Characteristics | No. of patients | Percent (%) |
| EGFR-TKI: epidermal growth factor receptor tyrosine kinase inhibitor. | ||
| Age (yr) | ||
| ≥65 | 18 | 12.9 |
| < 65 | 122 | 87.1 |
| Median (range) | 53（19-82） | |
| Gender | ||
| Male | 73 | 52 |
| Female | 67 | 48 |
| Performance status (First-line) | ||
| 0-1 | 123 | 88 |
| 2 | 17 | 12 |
| Performance status (Fourth-line) | ||
| 0-1 | 71 | 51 |
| 2-3 | 69 | 49 |
| Smoking history | ||
| Former | 48 | 34 |
| Never | 92 | 66 |
| Spouse | ||
| Living | 130 | 93 |
| Sick, divorced, unmarried | 10 | 7 |
| Histology | ||
| Squamous cell carcinoma | 24 | 17 |
| Others | 116 | 83 |
| EGFR mutation status | ||
| Positive | 41 | 29 |
| Negative | 34 | 24 |
| Unknown | 65 | 47 |
| Interval between first- and fourth-line therapy | ||
| ≥12 mo | 103 | 74 |
| < 12 mo | 37 | 26 |
| Stage Ⅳ when diagnosed | 140 | 100 |
| Whether contain EGFR-TKI or not before fourth-line therapy | ||
| Yes | 106 | 76 |
| No | 34 | 24 |