Table 2. Comparison of the baseline characteristics in the three study cohorts.
| Training set IGR n=2059 | Validation set 1 CRH n=4461 | P* value | Validation set 2 MDACC n=2550 | P** value | |
|---|---|---|---|---|---|
| Age, median (range) | 60 (23–96) | 58 (21–95) | <0.001 | 50 (19–91) | <0.001 |
| Clinical tumour size in mm median (range) | 16 (2–200) | 15 (0–200) | 0.91 | 35 (0–200) | <0.001 |
| Clinical node status (%) | <0.001 | ||||
| Negative | 1693 (82.2) | 3750 (84.1) | 858 (33.6) | ||
| Positive | 366 (17.8) | 711 (15.9) | 1692 (66.4) | ||
| Oestrogen receptor status (%) | 0.65 | <0.001 | |||
| Negative | 400 (19.4) | 890 (20) | 893 (35) | ||
| Positive | 1659 (80.6) | 3571 (80) | 1657 (65) | ||
| Progesterone receptor status (%) | 0.96 | <0.001 | |||
| Negative | 741 (36) | 1601 (35.9) | 1303 (51.1) | ||
| Positive | 1318 (64) | 2860 (64.1) | 1247 (48.9) | ||
| Tumour grade (%) | <0.001 | <0.001 | |||
| 1–2 | 1417 (68.8) | 3357 (75.2) | 921 (36.1) | ||
| 3 | 642 (31.2) | 1104 (24.7) | 1629 (63.9) | ||
| HER2 (%) | <0.001 | <0.001 | |||
| Positive | 260/1807 (14.4) | 492/4349 (11.3) | 382/1909 (20) | ||
| Negative | 1547/1807 (85.6) | 3857/4349 (88.7) | 1527/1909 (80) | ||
| Unknown | 252 (12.2) | 112 (2.5) | 641 (25.1) | ||
| Synchronous metastases | 91 (4.4) | 144 (3.2) | 0.02 | 129 (5.1) | 0.35 |
Abbreviations: CRH= Institut Curie-René Huguenin; IGR= Institut Gustave Roussy; MDACC=MD Anderson Cancer Center.
P* value IGR vs CRH; P** value IGR vs MDACC.