Non-Metastatic Osteosarcoma:
Variables included in the model for the whole cohort included failure to complete protocol (8.7 points), prior treatment (10.0 points), necrosis <90%: 4.3 points, neurovascular bundle involvement: 4.4 points, joint involvement: 6.3 points and SAP> median (204 U/l): 5.2 points (Table 7). In the validation cohort (n=158), factors that emerged significant and included in the final model were failure to complete protocol (7.1 points), prior treatment (10.0 points), necrosis <90%: 2.9 points, joint involvement: 5.1 points and SAP> median (204 U/l): 3.0 points (Table 8). Stratification was done by summation of the individual scores as follows; low risk (score <3), intermediate risk (3 - 8) and high risk (>8). Kaplan-Meier curves for EFS for the derivation (n=342), validation (n=158) and whole (n=600) cohort are depicted in Figure 2A[i], 2A[ii] and 2A[iii]. The c-index for whole, derivation and validation data are were 0.659, 0.664 and 0.651 respectively.