Fig. 4

Analysis of the receiver operating characteristic curves for normalization of carbohydrate antigen 19–9 (CA19–9) levels after neoadjuvant therapy. According to this analysis, 103 U/ml was the optimal pre-neoadjuvant therapy (pre-neoadjuvant therapy) carbohydrate antigen 19–9 (CA19–9) cut-off level, defined as no elevation after neoadjuvant therapy. The area under the curve was 0.937, and the sensitivity and specificity were 86.6 and 86.1%, respectively. According to these cut-off levels, 71 of 93 patients (76%) with pre-neoadjuvant therapy CA19–9 levels < 103 U/ml did not exhibit elevated CA19–9 levels after neoadjuvant therapy