Proposal of predictive model on survival in unresectable pancreatic cancer receiving systemic chemotherapy.

To construct a predictive model for overall survival (OS) in unresectable pancreatic cancer (PaC) undergoing systemic chemotherapy and to confirm its accuracy in an independent cohort. The training set (Ts) and the validation set (Vs) included 93 patients (median age=71 years) and 75 patients (median age=76 years). In the Ts, we examined variables linked to OS by uni- and multivariate analyses and constructed a predictive model for OS. Next, we evaluated the reproducibility of the proposed model in the Vs. In the multivariate analysis for the Ts, PaC stage IV (=0.0020) and carbohydrate antigen (CA) 19-9 ≥437.5 IU/l (=0.0237) were identified to be significant factors associated with OS. Patients with PaC stage IV or not were given a score of 1 or 0, whereas patients with CA19-9 ≥437.5 IU/l or <437.5 IU/l were given a score of 1 or 0. Sum of the point of PaC stage (0 or 1) and CA19-9 (0 or 1) was defined as "PaC-CA score". In the Ts, there were 16 patients with score 0, 40 with score 1 and 37 with score 2, while in the Vs, there were 9 patients with score 0, 32 with score 1 and 34 with score 2. Overall values reached significance in the Ts (=0.0002), the Vs (=0.0029) and the combined Ts and Vs (<0.0001) among patients with PaC score 0, 1 and 2. PaC-CA score can be helpful for risk stratification in PaC patients undergoing systemic chemotherapy.