Table 3. Performance of both models in the training data set.
| Royal Marsden Model | Model derived from the decision tree analysis | |
|---|---|---|
| Definition of high-risk patients | Patients with at least two of the following prognostic factors (albumin <35 g l−1, LDH > ULN and more than two metastatic sites) | Patients with albumin <33 g l−1 or patients with albumin ⩾33 g l−1 and with platelet counts ⩾400.000 mm−3 |
| Evaluable patients | 1760 (80.6%) | 1760 (80.6%) |
| Rate of early death in low-risk group | 137/1256 (10.9% (9.3–12.8)) | 122/1241 (9.8% (8.3–11.7)) |
| Rate of early death in high-risk group | 157/504 (31.1% (27.2–35.4)) | 172/519 (33.1% (29.1–37.4)) |
| Sensitivity | 0.53 (0.47–0.59) | 0.58 (0.53–0.64) |
| Specificity | 0.76 (0.74–0.78) | 0.76 (0.74–0.78) |
| Positive predictive value | 0.31 (0.27–0.35) | 0.33 (0.29–0.37) |
| Negative predictive value | 0.89 (0.87–0.90) | 0.90 (0.88–0.92) |
| Rate of well-classified patients | 0.72 (0.70–0.74) | 0.73 (0.71–0.75) |
| Discriminative slope | 20.1% (14.9–25.5) | 23.0% (18.0–28.0) |
| Brier score | 0.014 | 0.010 |
Abbreviations: LDH=lactate dehydrogenase; ULN=upper limit of normal.