Fig 1

Receiver-operating characteristic (ROC) curve for the scoring system. The area under the ROC curve was 0.791. According to the ROC curve, a cutoff value of 5 points was found to be best for distinguishing between patients without and with central LNM. The sensitivity and specificity were 64.7 and 80.5 %, respectively, and the positive predictive value and negative predictive value were 77.2 and 69.0 %, respectively. The dotted line represents the 95 % CI