Aoki S, et al. - In this study including patients with pancreatic adenocarcinoma, researchers investigated whether decreased carbohydrate antigen (CA) 19–9 levels post-neoadjuvant therapy had any prognostic significance. Participants were 240 consecutive patients who were treated with neoadjuvant therapy and subsequently underwent resection at seven high-volume institutions in Japan from 2001 to 2012. Three groups of patients were defined: those with no elevation [≤37 U/ml] before and after neoadjuvant therapy were considered as Normal group, those with elevated levels [> 37 U/ml] before neoadjuvant therapy but decreased levels [≤37 U/ml] afterwards were regarded as Responder group, and those with elevated levels [> 37 U/ml] after neoadjuvant therapy constituted the Non-responder group. Using uni- and multivariate analyses, the clinicopathological factors that affected overall survival were identified. Factors that significantly predicted overall survival were a CA19–9 level ≤ 103 U/ml, tumor size ≤27 mm, a lack of lymph node metastasis, and R0 status. Better prognosis, with a low incidence of hepatic recurrence post-operation, was predicted by decreased CA19–9 levels after neoadjuvant therapy.