Table 4 Multivariate analysis of distant disease-free survival for the HR+/HER2− pT1pN0 patients, including Ki-67 and risk of recurrence score as continuous and categorical variables

Ki-67 and ROR score as continuous variables

 Age

   < 55 years

1

1

   ≥ 55 years

1.71

0.50–5.80

0.391

1.10

0.41–3.00

0.849

 Grade

  I

1

1

  II

1.56

0.31–7.99

0.591

1.87

0.48–7.21

0.366

  III

1.26

0.16–9.86

0.827

2.25

0.40–12.61

0.355

 Ki-67

1.04

0.98–1.09

0.172

1.01

0.96–1.06

0.729

 ROR score

1.05

1.01–1.09

0.011

1.05

1.02–1.08

0.002

Ki-67 and ROR score as categorical variables

 Age

   < 55 years

1

1

   ≥ 55 years

1.36

0.44–4.23

0.598

1.06

0.41–2.72

0.912

 Grade

  I

1

1

  II

1.88

0.34–10.34

0.468

2.19

0.56–8.55

0.258

  III

1.70

0.22–13.01

0.609

2.62

0.47–14.50

0.271

 Ki-67

   < 15%

1

1

  15–30%

0.62

0.12–3.31

0.576

0.66

0.19–2.28

0.514

   > 30%

1.94

0.33–11.52

0.465

1.59

0.40–6.34

0.513

 ROR score

  Low

1

1

  Intermediate

9.56

1.01–90.87

0.049

4.52

1.08–18.85

0.038

  High

27.22

2.46–300.49

0.007

9.09

1.80–14.50

0.008