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Table 3 Cox regression analyses to identify the factors associated with progression-free survival (PFS)

From: Lower starting dose of afatinib for the treatment of metastatic lung adenocarcinoma harboring exon 21 and exon 19 mutations

Variables

Univariate analysis

Multivariable analysis - model 1 a

Multivariable analysis - model 2 a

HR [95% CI]

P value

HR [95% CI]

P value

HR [95% CI]

P value

Afatinib dose (40 mg daily vs. 30 mg daily)

0.86 [0.58–1.29]

0.4657

    

Sex (male vs. female)

1.19 [0.80–1.79]

0.3920

    

Age (≥65 vs. < 65)

0.79 [0.53–1.17]

0.2333

    

Smoking history (ever smokers vs. never smokers)

1.16 [0.71–1.89]

0.5659

    

ECOG (≥2 vs. ≤1)

1.11 [0.67–1.84]

0.6762

    

Exon 21 vs. exon 19 b

1.31 [0.89–1.95]

0.1751

  

1.56 [1.04–2.36]

0.0336

Number of metastatic sites/organs (1–2 vs. ≥3)

1.86 [1.20–2.88]

0.0055

1.83 [1.19–2.84]

0.0065

  

Metastatic site/organ on initial diagnosis: (yes vs. no)

 Brain

0.96 [0.62–1.49]

0.8479

    

 Lung

0.96 [0.64–1.44]

0.8318

    

 Pleura (or with pleural effusion)

1.57 [1.05–2.35]

0.0292

  

1.77 [1.17–2.69]

0.0075

 Bone

1.52 [1.02–2.27]

0.0385

  

1.69 [1.13–2.55]

0.0116

 Liver

1.50 [0.89–2.54]

0.1266

    

 Adrenal gland

0.96 [0.50–1.84]

0.8955

    

 Other site

0.84 [0.34–2.07]

0.7055

    

Dose reduction (yes vs. no)

0.56 [0.32–0.98]

0.0407

0.57 [0.33–0.99]

0.0467

0.59 [0.34–1.03]

0.0640

  1. aMultivariable Cox regression models were built using backward variable selection method, keeping only variables with p values less than 0.1. Number of metastatic sites/organs was considered while building model 1, whereas the detailed metastatic sites were considered while building model 2
  2. bThe patient with mutation in both exon 21 and exon 19 was arbitrary classified in to exon 21 group