Table 2 Cox’s proportional hazard regression model for overall survival (OS) and breast cancer specific survival (BCSS)

No. of participants

36553

4468

98197

2824

Age (years)

 ≤ 35

3330(9.11)

407(9.11)

1.00

3479(9.11)

258(9.14)

1.00

 > 35

33223(90.89)

4061(90.89)

1.04(0.94-1.15)

0.4945

34718(90.89)

2566(90.86)

1.03(0.91-1.17)

0.6453

Tumor size (cm)

 0 - 2

20608(56.38)

1323(29.61)

1.00

1.00

21185(55.46)

746(26.42)

1.00

1.00

 > 2

15945(43.62)

3145(70.39)

2.74(2.57-2.92)

<0.0001

1.70(1.58-1.82)

<0.0001

17012(44.54)

2078(73.58)

3.16(2.91-3.44)

<0.0001

1.77(1.61-1.93)

<0.0001

Axillary lymph node metastasis

 Negative

23731(64.92)

1474(32.99)

1.00

1.00

24439(63.98)

766(27.12)

1.00

1.00

 Positive

12822(35.08)

2994(67.01)

3.43(3.22-3.65)

<0.0001

2.95(2.75-3.16)

<0.0001

13758(36.02)

2058(72.88)

4.42(4.07-4.80)

<0.0001

3.50(3.20-3.84)

<0.0001

Operation method

 Mastectomy

19830(54.25)

3532(79.05)

1.00

1.00

21094(55.22)

2268(80.31)

1.00

1.00

 Conserving surgery

16723(45.75)

936(20.95)

0.37(0.34-0.39)

<0.0001

0.55(0.51-0.59)

<0.0001

17103(44.78)

556(19.69)

0.34(0.31-0.37)

<0.0001

0.55(0.50-0.61)

<0.0001

ER/PR expression

 ER and/or PR Positive

25647(70.16)

2519(56.38)

1.00

1.00

26629(69.71)

1537(54.43)

1.00

1.00

 ER and PR Negative

10906(29.84)

1949(43.62)

1.75(1.65-1.86)

<0.0001

1.55(1.42-1.70)

<0.0001

11568(30.29)

1287(45.57)

1.87(1.73-2.01)

<0.0001

1.56(1.40-1.74)

<0.0001

HER 2 expression

 Negative

26098(71.40)

2432(54.43)

1.00

1.00

27018(70.73)

1512(53.54)

1.00

1.00

 Positive

7040(19.26)

965(21.59)

1.42(1.32-1.53)

<0.0001

1.11(1.03-1.20)

0.0061

7402(19.38)

603(21.35)

1.41(1.29-1.55)

<0.0001

1.08(0.98-1.19)

0.1128

 Unknown

3415(9.34)

1071(23.97)

2.23(2.07-2.41)

<0.0001

1.70(1.58-1.84)

<0.0001

3777(9.89)

709(25.10)

2.45(2.23-2.68)

<0.0001

1.91(1.74-2.11)

<0.0001

BMI calssification

 Underweight BMI

1229(3.36)

158(3.54)

1.16(0.98-1.36)

0.0784

1.23(1.05-1.44)

0.0118

1284(3.36)

103(3.65)

1.18(0.97-1.44)

0.0974

1.26(1.03-1.54)

0.0219

 Normal BMI

24766(67.75)

2753(61.62)

1.00

1.00

25774(67.48)

1745(61.79)

1.00

1.00

 Overweight BMI

9164(25.07)

1319(29.52)

1.26(1.18-1.35)

<0.0001

1.15(1.07-1.23)

<0.0001

9651(25.27)

832(29.46)

1.25(1.15-1.36)

<0.0001

1.13(1.04-1.22)

0.0052

 Obese BMI

1394(3.81)

238(5.33)

1.51(1.32-1.72)

<0.0001

1.29(1.13-1.48)

0.0002

1488(3.90)

144(5.10)

1.42(1.19-1.68)

<0.0001

1.21(1.02-1.43)

0.0321

Histologic grade

 Low (grade1 - 2)

18316(50.11)

1727(38.65)

1.00

1.00

19002(49.75)

1041(36.86)

1.00

1.00

 High (Grade 3)

13631(37.29)

2259(50.56)

1.73(1.62-1.84)

<0.0001

1.32(1.23-1.41)

<0.0001

14401(37.70)

1489(52.73)

1.86(1.72-2.02)

<0.0001

1.36(1.25-1.48)

<0.0001

 Unknown

4606(12.60)

482(10.79)

1.02(0.92-1.13)

0.6849

1.04(0.94-1.15)

0.494

4794(12.55)

294(10.41)

1.04(0.92-1.19)

0.5269

1.08(0.95-1.23)

0.2561

Adjuvant chemotherapy

 Yes

25339(69.32)

3473(77.73)

1.00

1.00

26475(69.31)

2337(82.75)

1.00

1.00

 No

9002(24.63)

680(15.22)

0.58(0.53-0.63)

<0.0001

1.41(1.29-1.55)

<0.0001

9354(24.49)

328(11.61)

0.42(0.37-0.47)

<0.0001

1.12(0.99-1.28)

0.0753

 Unknown

2212(6.05)

315(7.05)

1.02(0.91-1.14)

0.7874

1.09(0.97-1.24)

0.1448

2368(6.20)

159(5.63)

0.75(0.64-0.88)

0.0005

0.79(0.67-0.94)

0.0062

Adjuvant hormonal

 Yes

23785(65.07)

2480(55.51)

1.00

1.00

24743(64.78)

1522(53.90)

1.00

1.00

 No

11000(30.09)

1782(39.88)

1.53(1.44-1.63)

<0.0001

1.07(0.98-1.17)

0.1399

11604(30.38)

1178(41.71)

1.63(1.51-1.76)

<0.0001

1.12(1.01-1.25)

0.0414

 Unknown

1768(4.84)

206(4.61)

1.13(0.98-1.30)

0.0920

1.02(0.88-1.19)

0.7627

1850(4.84)

124(4.39)

1.10(0.92-1.32)

0.3058

1.04(0.86-1.25)

0.6977