Table 2. Comparison of model performance between RSF model and 5 other models in predicting early recurrence.

Performance	Cohort	RSF	ERASL	Korean	AJCC TNM	BCLC	Chinese
Discrimination
Harrell’s C-index	Training	0.725 (0.005)	0.706 (0.006)	0.658 (0.006)	0.674 (0.006)	0.635 (0.006)	0.684 (0.006)
	Internal	0.762 (0.011)	0.726 (0.012)	0.672 (0.013)	0.711 (0.012)	0.646 (0.012)	0.709 (0.012)
	External	0.747 (0.016)	0.727 (0.017)	0.722 (0.017)	0.711 (0.017)	0.658 (0.018)	0.696 (0.018)
Gönen & Heller’s K	Training	0.684 (0.005)	0.672 (0.005)	0.638 (0.006)	0.647 (0.005)	0.616 (0.004)	0.642 (0.004)
	Internal	0.711 (0.008)	0.694 (0.010)	0.654 (0.011)	0.667 (0.008)	0.617 (0.008)	0.651 (0.008)
	External	0.697 (0.014)	0.689 (0.015)	0.688 (0.015)	0.657 (0.014)	0.619 (0.013)	0.632 (0.013)
Time-dependent AUC (2 years)	Training	0.818 (0.008)	0.791 (0.008)	0.721 (0.009)	0.747 (0.008)	0.689 (0.008)	0.757 (0.008)
	Internal	0.823 (0.014)	0.784 (0.016)	0.727 (0.017)	0.757 (0.015)	0.676 (0.014)	0.758 (0.016)
	External	0.785 (0.025)	0.783 (0.025)	0.780 (0.025)	0.749 (0.026)	0.678 (0.025)	0.717 (0.027)
Clinical usefulness
Net benefit at threshold 50%	Training	0.166	0.154	0.093	0.139	0.137	0.137
	Internal	0.121	0.092	0.041	0.095	0.073	0.073
	External	0.206	0.190	0.222	0.185	0.154	0.154
Overall performance
Time-dependent Brier (2 years)	Training	0.147	0.156	0.174	0.160	0.167	0.161
	Internal	0.129	0.143	0.159	0.144	0.154	0.146
	External	0.156	0.162	0.161	0.169	0.180	0.176
Time-dependent R2 (2 years)	Training	0.287	0.239	0.142	0.220	0.175	0.214
	Internal	0.306	0.233	0.145	0.220	0.150	0.206
	External	0.235	0.225	0.230	0.187	0.125	0.140

The parentheses are standard errors. AUC, areas under receiver operating characteristic curve; RSF, random survival forests; ERASL, early recurrence after surgery for liver tumor; AJCC TNM, American Joint Committee on Cancer tumor-node-metastasis; BCLC, Barcelona Clinic Liver Cancer.