Table 4.
Comparison of the prognostic performance of the AJCC 8th edition ypTNM staging system and the modified ypTNM staging system
| Variable | ypTNM staging (AJCC 8th) | Modified ypTNM staging | p value |
|---|---|---|---|
| Development cohort (internal validation) | |||
| Harrell's C‐index a | 0.589 (0.572–0.605) | 0.620 (0.602–0.638) | <.001 |
| AIC b | 14,867.50 | 14,793.55 | <.001 |
| Likelihood ratio chi‐square c | 140.71 | 218.66 | <.001 |
| Mean difference in BIC (95% CI) d | 64.94 (25.55–96.46) | ||
| NRI (95% CI) | 35.54% (14.04%–43.12%) | <.001 | |
| IDI (95% CI) | 0.032 (0.012–0.053) | .002 | |
| Validation cohort (external validation) | |||
| Harrell's C‐index a | 0.631 (0.591–0.671) | 0.668 (0.625–0.712) | .014 |
| AIC b | 1,461.06 | 1,443.6 | <.001 |
| Likelihood ratio chi‐square c | 28.75 | 45.15 | <.001 |
| Mean difference in BIC (95% CI) d | 17.50 (1.98–32.88) | ||
| NRI (95% CI) e | 44.26% (10.00%–66.18%) | <.001 | |
| IDI (95% CI) e | 0.048 (0.000–0.086) | .048 | |
Abbreviations: AIC, Akaike information criterion; AJCC 8th, American Joint Committee on Cancer 8th edition; BIC, Bayesian information criteria; CI, confidence interval; IDI, integrated discrimination improvement index; NRI, net reclassification index.
A higher Harrell's C‐index indicates higher discriminative ability.
Smaller AIC values indicate better optimistic prognostic stratification.
A higher likelihood ratio chi‐square score indicates better homogeneity.
The BIC was used to assess the overall prognostic performance of different prognostic systems via bootstrap‐resampling analysis.
NRI and IDI quantify the improvement by the new staging system in predicting the patient's 5‐year survival.