Fig. 1

Receiver operating characteristic (ROC) curve analysis of locoregional recurrence (LR) and distant metastasis prediction according to the pretherapeutic SUVmax of the primary tumor. A ROC curve for LR showing a lack of significant correlation [area under the curve (AUC) = 0.487] (95% CI = 0.371–0.604, P = 0.837). B ROC curve for distant metastasis. The area under the ROC curve was 0.709 (95% CI = 0.618–0.800, P = 0.001), and 13.9 was determined as the best potential cutoff value based on the Youden index. The sensitivity and specificity for an SUVmax of 13.9 were 93.5% and 51.5%, respectively