Table 6.
Cox proportional hazards regression analyses for identifying the relationship between clinical features and progression-free survival in patients with stage IV lung cancer harboring uncommon mutation receiving first-line TKI.
| Univariate Analysis | Multivariable Analyses | ||||
|---|---|---|---|---|---|
| Model 1 | Model 2 | Model 3 | Model 4 | ||
| Sex | |||||
| Female | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Male | 1.50 [0.83–2.72] | 2.83 [1.04–7.72] | 2.90 [1.07–7.88] | 2.13 [1.11–4.09] | 2.10 [1.11–3.97] |
| Age (year) | |||||
| <65 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| ≥65 | 0.52 [0.28–0.95] | 0.27 [0.12–0.58] | 0.28 [0.13–0.60] | 0.35 [0.17–0.72] | 0.35 [0.17–0.73] |
| Smoking history | |||||
| Never | 1.00 | 1.00 | 1.00 | ||
| Current | 1.33 [0.70–2.52] | 0.44 [0.14–1.42] | 0.46 [0.15–1.46] | ||
| Performance status | |||||
| ECOG 0–1 | 1.00 | 1.00 | 1.00 | ||
| ECOG 2–4 | 1.60 [0.85–3.02] | 1.51 [0.60–3.84] | 1.52 [0.62–3.74] | ||
| Number of metastatic sites | |||||
| =1 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| ≥2 | 1.60 [0.85–3.02] | 1.65 [0.78–3.51] | 1.87 [0.89–3.94] | 1.75 [0.87–3.54] | 1.73 [0.84–3.58] |
| Mutation site classified by exon | |||||
| Mutation only in exon 18 | 1.02 [0.36–2.84] | 1.31 [0.42–4.09] | 1.11 [0.38–3.20] | ||
| Mutation only in exon 20 | 2.25 [0.78–6.47] | 3.70 [0.93–14.83] | 2.84 [0.94–8.60] | ||
| Mutation only in exon 21 | 1.53 [0.54–4.38] | 1.84 [0.53–6.43] | 1.59 [0.51–5.01] | ||
| Mutations in multiple exons | 1.00 | 1.00 | 1.00 | ||
| Mutation site classified by susceptibility † | |||||
| Single sensitizing uncommon mutation | 0.57 [0.29–1.10] | 0.39 [0.16–0.96] | 0.48 [0.23–1.02] | ||
| Multiple sensitizing mutations | 0.43 [0.15–1.21] | 0.27 [0.07–1.01] | 0.34 [0.12–1.01] | ||
| A sensitizing mutation and a resistant uncommon mutation | 0.19 [0.04–0.85] | 0.20 [0.04–1.08] | 0.18 [0.04–0.83] | ||
| Other resistant uncommon mutations | 1.00 | 1.00 | 1.00 | ||
| TKI medication | |||||
| Afatinib | 1.00 | 1.00 | 1.00 | ||
| Gefitinib | 0.90 [0.46–1.76] | 1.85 [0.76–4.46] | 1.90 [0.82–4.43] | ||
| Erlotinib | 0.46 [0.16–1.30] | 0.91 [0.27–3.05] | 1.24 [0.37–4.19] | ||
Model 1 and Model 2 are maximal models. Model 3 and Model 4 are reduced multivariable models developed with backward variable selection method, keeping only variables with p value less than 0.15, from Model 1 and Model 2, respectively. † 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.