Table 3.

Comparison of multivariable Cox models for RFS to estimate the contribution of individual prognostic factors according to Harrell’s C-index

Combinations of prognostic factors	Harrell C-index	Difference (reduction) of Harrell C-index (vs. full model)	95% CI of difference
Nine factors (full model)a	0.6957	–	–
Eight factors excluding NLNE from the full model	0.6966	−0.0008	−0.0044 to 0.0079
Eight factors excluding tumour differentiation from the full model	0.6941	0.0017	−0.0023 to 0.0143
Eight factors excluding T-stage from the full model	0.6826	0.0132	0.0005 to 0.0329
Eight factors excluding lymphatic invasion from the full model	0.6940	0.0017	−0.0027 to 0.0084
Eight factors excluding venous invasion from the full model	0.6963	−0.0006	−0.0047 to 0.0081
Eight factors excluding MSI from the full model	0.6881	0.0077	−0.0008 to 0.0198
Eight factors excluding treatment arm from the full model	0.6939	0.0019	−0.0021 to 0.0133
Eight factors excluding tumour budding from the full model	0.6843	0.0114	−0.0015 to 0.0329
Eight factors excluding DR from the full model	0.6761	0.0196	0.0020– 0.0449

RFS relapse-free survival, NLNE the number of lymph node examined, MSI microsatellite instability, MSS microsatellite stable, UFT tegafur–uracil, CI confidence interval.

Only 961 patients with MSI values were analysed.

Bold values indicates that the factors are associated with a substantially reduced Harrell C-index (95% CI of difference does not contain zero).

^aPrognostic model consisting of nine elemental prognostic factors {number of lymph nodes examined (<12; ≥12), tumour differentiation (G1; G2; G3), T-stage (T3; T4), lymphatic invasion (negative; positive), venous invasion (negative; positive), MSI (MSI-Low/MSS; MSI-High), treatment arm (surgery alone; UFT), tumour budding (BD1; BD2; BD3), and DR (mature; intermediate; immature)}.