Table 5.

Comparison of predictive power between models.

	Model 1	Model 1 +Postoperative Calcitonin	Model 1 +Lymph Node Ratio	Model 2
C-index (SD)	0.762 (0.036)	0.797 (0.034)	0.810 (0.036)	0.850 (0.034)
p	(reference)	0.100	0.089	0.002

SD, standard deviation.