Table 1.
Clinical characteristics of patients with EGFR mutant NSCLC with skeletal metastasis according to first progression sites
| Clinical characteristic | Skeletal region only (n=37) | Extraskeletal±skeletal regions (n=39) | p-value |
|---|---|---|---|
| Age, mean (yr) | 58.2 | 62.6 | 0.061 |
| Sex | |||
| Male | 15 (40.5) | 13 (33.3) | - |
| Female | 22 (59.5) | 26 (66.7) | |
| ECOG | |||
| 0/1 | 20 (54.1) | 22 (56.4) | - |
| ≥ 2 | 17 (45.9) | 17 (43.6) | |
| Smoking | |||
| Never | 24 (62.2) | 29 (74.4) | - |
| Current/former | 13 (37.8) | 10 (25.6) | |
| EGFR mutation | |||
| Exon 19 del | 19 (51.4) | 17 (43.6) | - |
| Exon 21 L858R | 12 (32.4) | 19 (48.7) | |
| Exon 18 G719X | 3 (8.1) | 1 (2.6) | |
| Exon 21 L861Q | 2 (5.4) | 2 (5.1) | |
| Exon 19 insertion | 1 (2.7) | ||
| No. of bone metastases | |||
| Single | 4 (10.8) | 12 (30.8) | 0.048 |
| Multiple | 33 (89.2) | 27 (69.2) | |
| Brain metastasis | |||
| No | 20 (54.1) | 16 (41.0) | - |
| Yes | 17 (45.9) | 23 (59.0) | |
| Extrathoracic metastasis (except bone and brain) | |||
| No | 28 (75.7) | 27 (69.2) | - |
| Yes | 9 (24.3) | 12 (30.8) | |
| Management of skeletal metastasis before EGFR-TKIs | |||
| No | 17 (48.5) | 26 (65.1) | 0.068 |
| Yes | 20 (51.5) | 13 (34.9) | |
| Sort of EGFR-TKI | |||
| Gefitinib | 25 (67.6) | 21 (53.8) | - |
| Erlotinib | 12 (32.5) | 17 (43.6) | |
| Line of EGFR-TKI | |||
| 1st line | 25 (67.6) | 21 (53.8) | - |
| 2nd/3rd line | 12 (32.4) | 18 (46.2) | |
| Response to EGFR-TKIs | |||
| CR/PR | 31 (84.8) | 34 (80.0) | - |
| SD | 6 (15.2) | 4 (11.6) | |
| PD | 1 (2.3) | ||
| Progression sites at the time of stopping EGFR-TKI | 31 | 29 | |
| Extraskeletal regions only | 4 (12.9) | 19 (67.9) | 0.001 |
| Skeletal and extraskeletal regions | 19 (61.3) | 10 (32.1) | |
| Skeletal regions only | 8 (25.8) | ||
| Disease flare at stopping EGFR-TKI | 7 (22.5) | 4 (14.3) | 0.147 |
| Overall TTP, median (95% CI, mo) | 17.2 (13.1-21.1) | 10.4 (7.4-14.4) | 0.031 |
| OS, median (95% CI, mo) | 37.2 (14.1-61.2) | 37.3 (28.1-46.1) | 0.639 |
Values are presented as number (%) unless otherwise indicated. EGFR, epidermal growth factor receptor; NSCLC, non-small cell lung cancer; ECOG, Eastern Cooperative Oncology Group; TKI, tyrosine kinase inhibitor; CR, complete response; PR, partial response; SD, stable disease; PD, progressive disease; TTP, time to progression; CI, confidence interval; OS, overall survival.