Table 4.
Characteristics of the patients with stage IV lung cancer harboring uncommon mutation receiving a first-line tyrosine kinase inhibitor (TKI), classified by the drug used.
| Afatinib | Gefitinib | Erlotinib | p Value * | |
|---|---|---|---|---|
| n | 17 (30%) | 31 (54%) | 9 (16%) | |
| Age (year), mean ± SD | 64 ± 9 | 67 ± 14 | 62 ± 11 | 0.4356 |
| Age (year), median (IQR) | 65 (61–70) | 67 (56–80) | 61 (55–67) | 0.4356 |
| Age (year), n (%) | 0.5820 | |||
| <65 | 11 (65%) | 15 (48%) | 5 (56%) | |
| ≥65 | 6 (35%) | 16 (52%) | 4 (44%) | |
| Sex, n (%) | 0.1084 | |||
| Female | 8 (47%) | 16 (52%) | 8 (89%) | 0.2477 |
| Male | 9 (53%) | 15 (48%) | 1 (11%) | |
| Smoking history, n (%) | 0.2477 | |||
| Never | 13 (76%) | 19 (61%) | 8 (89%) | |
| Current | 4 (24%) | 12 (39%) | 1 (11%) | |
| Performance status, n (%) | 0.3383 | |||
| ECOG 0–1 | 10 (59%) | 21 (68%) | 8 (89%) | |
| ECOG 2–4 | 7 (41%) | 10 (32%) | 1 (11%) | |
| Number of metastatic sites, n (%) | 0.3891 | |||
| =1 | 6 (35%) | 17 (55%) | 4 (44%) | |
| ≥2 | 11 (65%) | 14 (45%) | 5 (56%) | |
| Metastatic site, n (%) | ||||
| Brain | 6 (35%) | 5 (16%) | 3 (33%) | 0.2500 |
| Leptomeningeal | 2 (12%) | 0 (0%) | 0 (0%) | 0.1078 |
| Lung | 9 (53%) | 8 (26%) | 3 (33%) | 0.1661 |
| Bone | 8 (47%) | 17 (55%) | 5 (56%) | 0.9344 |
| Pleural | 7 (41%) | 19 (61%) | 3 (33%) | 0.2398 |
| Pericardial | 4 (24%) | 1 (3%) | 0 (0%) | 0.0542 |
| Liver | 3 (18%) | 5 (16%) | 1 (11%) | 1.0000 |
| Adrenal | 2 (12%) | 2 (6%) | 1 (11%) | 0.6897 |
| Mutation site classified by exon, n (%) | 0.2374 | |||
| Mutation only in exon 18 | 4 (24%) | 14 (45%) | 3 (33%) | |
| Mutation only in exon 20 | 8 (47%) | 7 (23%) | 1 (11%) | |
| Mutation only in exon 21 | 2 (12%) | 7 (23%) | 4 (44%) | |
| Mutations in multiple exons | 3 (18%) | 3 (10%) | 1 (11%) | |
| Mutation site classified by susceptibility †, n (%) | 0.1599 | |||
| Single sensitizing uncommon mutation | 5 (29%) | 16 (52%) | 6 (67%) | |
| Multiple sensitizing mutations | 3 (18%) | 3 (10%) | 1 (11%) | |
| A sensitizing mutation and a resistant uncommon mutation | 0 (0%) | 4 (13%) | 1 (11%) | |
| Other resistant uncommon mutations | 9 (53%) | 8 (26%) | 1 (11%) | |
| Initial response to TKI, n (%) | 0.1943 | |||
| Partial response | 7 (41%) | 9 (29%) | 3 (33%) | |
| Stable disease | 5 (29%) | 11 (35%) | 6 (67%) | |
| Progressive disease | 5 (29%) | 11 (35%) | 0 (0%) | |
| Response rate to TKI | 7 (41%) | 9 (29%) | 3 (33%) | 0.7450 |
| Disease control rate with TKI | 12 (71%) | 20 (65%) | 9 (100%) | 0.0914 |
| Median PFS on TKI (month) | 5.5 | 6.2 | 9.0 | 0.3025 |
| Median OS (month) | 20.5 | 16.1 | 12.1 | 0.9116 |
* Kruskal-Wallis test or Fisher’s exact test or Log-rank test. † Mutation site classified by susceptibility: “Single sensitizing uncommon mutation” included exon18 G719X and exon21 L861Q; “multiple sensitizing mutations” included exon18 G719X + exon20 S768I, exon18 G719X + exon21 L861Q, and exon21 L858R + exon20 S768I; “a sensitizing mutation and a resistant uncommon mutation” included exon18 G719X + exon18 other and exon21 L858R + exon20 Q812*; “other resistant uncommon mutations” included exon 18 other mutation, exon 20 insertion, and exon 20 point mutation.