Table 3 Univariate/multivariate Cox-regression analysis for real-world progression-free survival

  ≥ 60 vs < 60

0.70

0.478–1.024

0.066

–

–

–

 Unknown vs 0

1.22

0.748–1.991

0.425

0.95

0.555–1.621

0.848

  ≥ 1 vs 0

1.81

1.161–2.824

0.009

1.81

1.158–2.843

0.009

Recurrent / de novo, recurrent vs de novo

0.68

0.461–1.017

0.061

0.64

0.423–0.968

0.034

CNS metastasis, yes vs no

1.02

0.577–1.790

0.956

–

–

–

Visceral metastasis, yes vs no

1.08

0.715–1.623

0.724

–

–

–

Hormone receptor status, positive vs negative

0.97

0.650–1.449

0.883

–

–

–

HER2 status, IHC 3+ vs IHC 2+/ISH + or IHC unknown/ISH+

0.60

0.374–0.961

0.034

0.52

0.307–0.864

0.012

Number of treatment lines before T-DM1 treatment, ≥ 2 vs < 2

1.01

0.688–1.491

0.949

–

–

–

History of pertuzumab treatment, yes vs no

1.55

1.054–2.286

0.026

1.28

0.855–1.903

0.232

History of lapatinib treatment, yes vs no

0.94

0.620–1.439

0.789

–

–

–

 Yes (both) vs no (both)

1.38

0.784–2.421

0.265

–

–

–

 Yes (either one) vs no (both)

1.57

0.876–2.810

0.130

–

–

–

 CR or PR vs SD, non-CR/non-PD, PD, or unknown

0.70

0.468–1.040

0.077

–

–

–

  ≥ 12 months vs < 6 months

0.57

0.339–0.959

0.034

0.55

0.318–0.959

0.035

 6–12 months vs < 6 months

0.60

0.377–0.940

0.026

0.65

0.401–1.064

0.087

  ≥ 2 months vs < 1 month

0.71

0.405–1.245

0.233

–

–

–

 1–2 months vs < 1 month

1.28

0.843–1.942

0.247

–

–

–

 Anti-HER2 therapy vs without anti-HER2 therapy

0.50

0.305–0.814

0.005

0.48

0.282–0.826

0.008