Table 2.

Multivariable analysis of conditional landmark cohort (N = 8,496).

Variables	N	Events	HR	95%CI (lower–upper)		P value
All patients	8496	3820
Radiotherapy
No	5709	2804	1.00
Yes	2787	1016	0.74	0.69	0.80	< 0.001
Age
< 55	3585	1421	1.00
55-	4911	2399	1.26	1.18	1.35	< 0.001
Race
White	6790	3028	1.00
Black	1342	661	1.07	0.99	1.17	0.103
Others	364	131	0.94	0.79	1.13	0.516
Charlson-Deyo score
0	7119	3064	1.00
1	1089	584	1.29	1.18	1.41	< 0.001
2 or more	288	172	1.45	1.24	1.70	< 0.001
cT
1	1400	575	1.00
2	3181	1382	1.07	0.96	1.18	0.214
3	1487	664	1.15	1.02	1.29	0.021
4	2428	1199	1.28	1.15	1.43	< 0.001
cN
0	2626	1142	1.00
1	3479	1525	1.03	0.95	1.12	0.484
2	1157	585	1.13	1.02	1.25	0.025
3	1234	568	1.04	0.94	1.17	0.439
Grade
1, 2	3829	1463	1.00
3, 4	4667	2357	1.55	1.44	1.66	< 0.001
Subtypes
Luminal	4897	2209	1.00
HER2 +	2389	828	0.61	0.56	0.67	< 0.001
Triple-negative	1210	783	1.68	1.50	1.89	< 0.001
Breast surgery
BCS	2254	968	1.00
Mastectomy	6242	2852	1.07	0.99	1.16	0.069
Chemotherapy
No	2215	1125	1.00
Yes	6281	2695	0.84	0.77	0.91	< 0.001
Endocrine therapy
No	3084	1562	1.00
Yes	5412	2258	0.78	0.72	0.86	< 0.001
Bone metastasis
Yes	4939	2255	1.00
No	3557	1565	0.80	0.73	0.87	< 0.001
Lung metastasis
Yes	1832	968	1.00
No	6664	2852	0.84	0.76	0.92	< 0.001
Liver metastasis
Yes	1495	778	1.00
No	7001	3042	0.71	0.64	0.79	< 0.001
Brain metastasis
Yes	209	125	1.00
No	8287	3695	0.70	0.58	0.85	< 0.001
No. of metastatic sites
1	6554	2736	1.00
2	1549	840	1.18	1.07	1.30	< 0.001
3 or more	393	244	1.25	1.03	1.50	0.021

HR hazard ratio, CI confidential interval, cT clinical T, cN clinical N, BCS breast conserving surgery.