Table 1. Patient characteristics.
| Variable | Total, n (%) | Age | PS | |||||
|---|---|---|---|---|---|---|---|---|
| Young patients, n (%) | Elderly patients, n (%) | P value | 0–1, n (%) | 2–4, n (%) | P value | |||
| Subjects | 31 | 8 (25.8) | 23 (74.2) | 21 (67.7) | 10 (32.3) | |||
| Median age [range] | 72 [34–88] | 54 [34–64] | 75 [65–88] | 0.0001 | 70 [34–84] | 70.5 [51–88] | 0.028 | |
| Sex | 0.64 | 0.21 | ||||||
| Male | 7 (22.6) | 1 (12.5) | 6 (26.1) | 4 (19.0) | 3 (30.0) | |||
| Female | 24 (77.4) | 7 (87.5) | 17 (73.9) | 17 (81.0) | 7 (70.0) | |||
| ECOG-PS | 0.22 | |||||||
| 0–1 | 21 (67.7) | 7 (87.5) | 14 (60.9) | – | – | |||
| 2–4 | 10 (32.3) | 1 (12.5) | 9 (39.1) | – | – | |||
| Smoking history | 1 | 1 | ||||||
| Never smoker | 21 (67.7) | 5 (62.5) | 16 (69.6) | 14 (66.7) | 7 (70.0) | |||
| Ever or current smoker | 10 (32.3) | 3 (37.5) | 7 (30.4) | 7 (33.3) | 3 (30.0) | |||
| Previous therapy | ||||||||
| First EGFR-TKI treatment | 0.15 | 0.51 | ||||||
| Gef | 24 (77.4) | 5 (62.5) | 19 (82.6) | 15 (71.4) | 9 (90.0) | |||
| Erl | 5 (16.1) | 3 (37.5) | 2 (8.7) | 4 (19.0) | 1 (10.0) | |||
| Afa | 2 (6.5) | 0 (0.0) | 2 (8.7) | 2 (9.5) | 0 (0.0) | |||
| Platinum doublet | 1 | 0.015 | ||||||
| Yes | 22 (71.0) | 6 (75.0) | 16 (51.6) | 18 (85.7) | 4 (40.0) | |||
| No | 9 (29.0) | 2 (25.0) | 7 (30.4) | 3 (14.3) | 6 (60.0) | |||
| Median osimertinib sequence [range] | 3 [2–7] | 4 [2–5] | 3 [2–7] | 0.32 | 3 [2–7] | 2.5 [2–7] | 0.54 | |
| Mutation type | 0.67 | 0.59 | ||||||
| Ex19del | 19 (61.3) | 4 (50.0) | 15 (65.2) | 14 (66.7) | 5 (50.0) | |||
| L858R | 10 (32.3) | 4 (50.0) | 6 (26.1) | 6 (28.6) | 4 (40.0) | |||
| Others | 2 (6.5) | 0 (0.0) | 2 (8.7) | 1 (4.8) | 1 (10.0) | |||
| T790M detection sample | 0.68 | 0.27 | ||||||
| Tissue | 12 (38.7) | 2 (25.0) | 10 (43.5) | 6 (28.6) | 6 (60.0) | |||
| Liquid | 21 (67.7) | 6 (75.0) | 15 (65.2) | 15 (71.4) | 6 (60.0) | |||
| Both | 2 (6.5) | 0 (0.0) | 2 (8.7) | 0 (0.0) | 2 (20.0) | |||
| CNS metastasis | 0.41 | 0.0089 | ||||||
| Yes | 14 (45.2) | 5 (62.5) | 9 (39.1) | 13 (61.9) | 1 (10.0) | |||
| No | 17 (54.8) | 3 (37.5) | 14 (60.9) | 8 (38.1) | 9 (90.0) | |||
PS, performance status; EGFR-TKI, epidermal growth factor receptor-tyrosine kinase inhibitor; CNS, central nervous system.