Table 7.
Cox proportional hazards regression analyses for identifying the relationship between clinical features and overall 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 | ||
| Sex | ||||
| Female | 1.00 | 1.00 | 1.00 | 1.00 |
| Male | 2.31 [1.19–4.47] | 1.81 [0.65–4.98] | 1.86 [0.67–5.16] | 1.83 [0.88–3.78] |
| Age (year) | ||||
| <65 | 1.00 | 1.00 | 1.00 | 1.00 |
| ≥65 | 1.04 [0.55–1.98] | 0.45 [0.18–1.12] | 0.46 [0.19–1.15] | 0.47 [0.20–1.14] |
| Smoking history | ||||
| Never | 1.00 | 1.00 | 1.00 | |
| Current | 2.40 [1.21–4.74] | 1.11 [0.37–3.3] | 1.1 [0.36–3.33] | |
| Performance status | ||||
| ECOG 0–1 | 1.00 | 1.00 | 1.00 | 1.00 |
| ECOG 2–4 | 2.77 [1.42–5.39] | 3.43 [1.21–9.75] | 3.32 [1.19–9.28] | 3.40 [1.32–8.72] |
| Number of metastatic sites | ||||
| =1 | 1.00 | 1.00 | 1.00 | |
| ≥2 | 2.77 [1.42–5.39] | 1.10 [0.49–2.46] | 1.20 [0.55–2.60] | |
| Mutation site classified by exon | ||||
| Mutation only in exon 18 | 1.39 [0.45–4.30] | 1.56 [0.43–5.62] | ||
| Mutation only in exon 20 | 1.73 [0.55–5.48] | 1.26 [0.34–4.73] | ||
| Mutation only in exon 21 | 1.95 [0.61–6.24] | 1.90 [0.43–8.48] | ||
| Mutations in multiple exons | 1.00 | 1.00 | ||
| Mutation site classified by susceptibility | ||||
| Single sensitizing uncommon mutation | 0.86 [0.41–1.78] | 1.15 [0.49–2.7] | ||
| Multiple sensitizing mutations | 0.56 [0.18–1.74] | 0.75 [0.21–2.67] | ||
| A sensitizing mutation and a resistant uncommon mutation | 1.01 [0.33–3.12] | 1.23 [0.34–4.44] | ||
| Other resistant uncommon mutations | 1.00 | 1.00 | ||
| TKI medication | ||||
| Afatinib | 1.00 | 1.00 | 1.00 | |
| Gefitinib | 1.04 [0.48–2.24] | 0.85 [0.33–2.21] | 0.91 [0.35–2.36] | |
| Erlotinib | 0.83 [0.25–2.71] | 0.93 [0.22–3.95] | 1.01 [0.22–4.49] | |
* Model 1 and Model 2 are maximal models. Model 3 is a reduced multivariable models developed with backward variable selection method, keeping only variables with p value less than 0.15, from both Model 1 and Model 2. † 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.