Table 5 Univariable and multivariable cox proportional hazard regression analysis of risk factors potentially associated with iPFS in EGFR-mutated lung adenocarcinoma patients with brain metastases

Gender (Male vs. Female)

0.080

Age (≥ 60 vs.<60)

0.027

0.134

1.394

0.903

2.153

Smoker (Yes vs.No)

0.388

KPS (< 80 vs.≥80)

0.008

0.008

1.933

1.190

3.139

Location (Left lung vs.Right)

0.889

EGFR mutation type (Common vs. Uncommon)

0.005

0.005

0.328

0.150

0.716

Number of BMs (≤ 5 vs.>5)

0.000

0.000

0.163

0.098

0.272

Volume of BMs

0.008

0.182

1.000

1.000

1.000

Location of BMs (Only in the hemispheres of the brain vs. Exist in other location)

0.002

0.829

1.058

0.636

1.758

Symptoms of BM (Yes vs.No)

0.455

T categories of TNM (1 vs.>1)

0.133

N categories of TNM (< 3 vs.≥3)

0.725

Hepatic metastases (Yes vs.No)

0.124

Bone metastases (Yes vs.No)

0.277

Pleural metastasis (Yes vs.No)

0.496

Adrenal metastasis (Yes vs.No)

0.316

Combined with chemotherapy or antiangiogenic therapy (Yes vs.No)

0.608

First-line therapy (Yes vs.No)

0.000

0.000

2.880

1.869

4.437