Plasma thymidine kinase activity as a prognostic biomarker in pancreatic ductal adenocarcinoma: a single-center prospective study.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) patients might benefit from a biomarker to more precisely prognosticate their overall survival to make more informed treatment and surveillance decisions. The aim of the study was to assess the circulating biomarker Thymidine kinase (TK) activity in samples from patients with PDAC to improve prognostic precision.

MATERIAL AND METHODS: Using the sensitive TK activity (TKa) assay DiviTum®, serum samples from 60 PDAC patients were analyzed.

RESULTS: Median TKa value for patients with PDAC was 931 Du/L. TK activity <931 and CA19-9 < 37 was prognostic for a longer survival, compared to patients with any or both TK activity >931 and CA19-9 > 37, with median 41.3 vs 8.6 months from sample to death ( p  < 0.001), and 3-year survival was 55.6% vs 8.9% ( p  < 0.001). Hazard ratio was 2.81 if any or both of TK or CA19-9 were above the cut-off value ( p  < 0.05).

UNLABELLED: TKa in combination with CA19-9 outperforms each marker individually for prediction of survival. Overall survival is longer in patients with both TKa <931 Du/L and CA19-9 < 37. Further studies of TKa levels at different disease stages and correlation to outcome is warranted to find the full potential clinical usage of the TKa marker in PDAC.