Table 1. Characteristics of breast cancer patients and associations with disease-free survival (DFS).
| Discovery set | Replication set | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ntotal | (%) | Nevent | (%) | HR a | (95% CI) | Ntotal | (%) | Nevent | (%) | HR a | (95% CI) | |
| No. of patients | 1,732 | (100.0) | 214 | (100.0) | 1,494 | (100.0) | 164 | (100.0) | ||||
| Median follow-up time, years (range) | 3.8 | (0.3–8.0) | 2.1 | (0.3–8.1) | 4.6 | (0.3–8.5) | 2.2 | (0.3–8.0) | ||||
| Total time at risk, person-years | 6978.4 | 562.0 | 6677.8 | 429.4 | ||||||||
| Median age at surgery, years (range) | 47 | (26–82) | 46 | (30–82) | 1.01 | (0.99–1.02) | 47 | (21–82) | 44 | (21–74) | 0.98 | (0.97–1.00) |
| Tumor size | ||||||||||||
| ≤2 cm | 942 | (54.4) | 69 | (32.2) | 1.00 | ref. | 798 | (53.4) | 54 | (32.9) | 1.00 | ref. |
| 2–5 cm | 648 | (37.4) | 109 | (50.9) | 1.58 | (1.15–2.18) | 638 | (42.7) | 94 | (57.3) | 1.63 | (1.15–2.32) |
| >5 cm | 98 | (5.7) | 33 | (15.4) | 2.95 | (1.87–4.64) | 51 | (3.4) | 16 | (9.8) | 3.25 | (1.79–5.87) |
| Nodal status | ||||||||||||
| negative | 1,059 | (61.1) | 80 | (37.4) | 1.00 | ref. | 933 | (62.5) | 68 | (41.5) | 1.00 | ref. |
| positive | 673 | (38.9) | 134 | (62.6) | 2.15 | (1.59–2.91) | 561 | (37.6) | 96 | (58.5) | 2.19 | (1.57–3.06) |
| TNM stage | ||||||||||||
| 0 | 167 | (9.6) | 5 | (2.3) | 0.44 | (0.18–1.12) | 29 | (1.9) | 0 | (0.0) | - | |
| I | 596 | (34.4) | 43 | (20.1) | 1.00 | ref. | 566 | (37.9) | 35 | (21.3) | 1.00 | ref. |
| II | 694 | (40.1) | 87 | (40.7) | 1.51 | (1.04–2.18) | 705 | (47.2) | 82 | (50.0) | 1.85 | (1.24–2.75) |
| III | 275 | (15.9) | 79 | (36.9) | 4.15 | (2.84–6.06) | 194 | (13.0) | 47 | (28.7) | 4.63 | (2.97–7.22) |
| ER status | ||||||||||||
| positive | 1,069 | (61.7) | 100 | (46.7) | 1.00 | ref. | 921 | (61.7) | 81 | (49.4) | 1.00 | ref. |
| negative | 663 | (38.3) | 114 | (53.3) | 1.53 | (0.13–2.08) | 573 | (38.4) | 83 | (50.6) | 1.35 | (0.96–1.89) |
| PR status | ||||||||||||
| positive | 936 | (54.0) | 76 | (35.5) | 1.00 | ref. | 778 | (52.1) | 63 | (38.4) | 1.00 | ref. |
| negative | 793 | (45.8) | 138 | (64.5) | 1.75 | (1.28–2.39) | 714 | (47.8) | 101 | (61.6) | 1.33 | (0.94–1.89) |
| HER2 status | ||||||||||||
| negative | 1,270 | (73.3) | 152 | (71.0) | 1.00 | ref. | 1,186 | (79.4) | 107 | (65.2) | 1.00 | ref. |
| positive | 462 | (26.7) | 62 | (29.0) | 0.90 | (0.66–1.23) | 308 | (20.6) | 57 | (34.8) | 1.60 | (1.15–2.24) |
| Tumor subtypes | ||||||||||||
| HR+ HER2- | 995 | (57.5) | 91 | (42.5) | 1.00 | ref. | 907 | (60.7) | 68 | (41.5) | 1.00 | ref. |
| HR+ HER2+ | 241 | (13.9) | 26 | (12.2) | 1.11 | (0.72–1.73) | 162 | (10.8) | 28 | (17.1) | 1.87 | (1.20–2.93) |
| HR- HER2+ | 221 | (12.8) | 36 | (16.8) | 1.93 | (1.30–2.86) | 146 | (9.8) | 29 | (17.7) | 2.51 | (1.61–3.90) |
| HR- HER2- | 275 | (15.9) | 61 | (28.5) | 2.41 | (1.73–3.35) | 279 | (18.7) | 39 | (23.8) | 1.76 | (1.18–2.62) |
Abbreviations: DFS, disease-free survival; HR, hazard ratio; CI, confidence interval; ER, estrogen receptor; PR, progesterone receptor; HER2, human epidermal growth factor receptor 2; HR, hormone receptor; ref. reference.
aCox proportional hazard model adjusted for age, recruiting center, TNM stage, and tumor subtypes.