Tumor growth kinetics by CA 19-9 in patients with unresectable pancreatic cancer receiving chemotherapy: A retrospective analysis.

Background: Recently, measures of tumor growth kinetics calculated by carbohydrate antigen 19-9 (CA 19-9) determinations after cytotoxic chemotherapy (CHT) have been reported as effective prognostic indicators in locally-advanced unresectable and metastatic pancreatic adenocarcinoma (mPDAC). The study aims to evaluate the prognostic role of tumor kinetics measured by CA 19-9 in patients with mPDAC, measuring it by three different ways. Methods: Patients with mPDAC receiving a first-line CHT between 2009 and 2017 were identified, and those for whom CA 19-9 data were available were enrolled. Three CA 19-9-related variables were calculated: CA 19-9 related reduction rate (RR) and tumor growth rate (G), after 8 weeks of CHT, tumor growth and inflammation index (TGII), after 90 days of CHT. The relationships with the outcome were analysed, and a Cox model has been build with each of the three variables. Results: Of 118 patients only 48 were eligible for the analysis. RR, G, or TGII appear as significant prognostic factors, and, after multivariate analysis, a reduction rate of 20% the baseline or more was associated with good survival (HR 0.321; CIs 0.156-0.661) as well as a G > -0.4%/day (HR 2.114; CIs 1.034 -4.321), whereas TGII >190 was not correlated with the outcome (HR 1.788; CIs 0.789-4.055). Conclusions: In patients with mPDAC, after 8 weeks of first-line CHT, CA 19-9-related tumor reduction or growth rate appear as valuable prognostic factors. (C) 2020 Published by Elsevier B.V. on behalf of IAP and EPC.