Fig. 3

Receiver operating characteristic (ROC) curve analysis for LIM nomogram and pie charts for indicating the discriminatory power of LIM nomogram. In the training (a) and testing (b) groups of LIM nomogram, the AUC was respectively 0.794 (95% CI 0.778–0.808) and 0.775 (95% CI 0.748–0.802). The P values were two-sided. The maximum Youden index of the ROC curves were employed to distinguish the risk of liver metastasis in the training group (c) and the testing groups (d), respectively. The detailed statistics are provided in Additional file 2: Table S2 and Additional file 3: Table S3. The P values were two-sided and tested by Chi-square test. Abbreviations: ROC receiver operating characteristic, LIM liver metastasis, 95% CI 95% confidence interval