Postoperative nomogram predicting 1-, 2-, 3-year RFS probability. To predict the recurrence risk, users can obtain the score of each indicator first by drawing a line vertically to the scale labeled “Points”. Then, add up the corresponding scores of all the indicators. Finally, identify the position of the total score on the “Total Points” scale and draw a line vertically to the “1-Year RFS Probability”, “2-Year RFS Probability” and “3-Year RFS Probability” axes to estimate the probability of RFS. RFS, recurrence-free survival; CK20, cytokeratin 20.