Prognostic value of plasma circulating tumor (ct) DNA KRAS mutations and serum CA19-9 in unresectable pancreatic cancer (PC) patients.

4022 Background: Median overall survival (OS) time of patients with unresectable PC varies widely. Diagnostic tools are presently lacking to predict outcomes. The majority of pancreatic tumors have KRAS mutations. The study aim was to evaluate the utility of baseline and serial measurements of ctDNA KRAS mutation load, alone or in combination with serum CA 19-9, as an outcome prognostic biomarker in patients with unresectable PC undergoing palliative chemotherapy. Methods: In the Danish BIOPAC prospective biomarker study, plasma was collected from 182 unresectable PC patients (85 females, 97 males, median age 68, range 45-89 years; locally advanced disease n = 48; metastatic n = 134) undergoing treatment with gemcitabine (n = 151) or FOLFIRINOX (n = 31). ctDNA KRAS G12/13 mutation levels in archival ( ≤ 6 years) plasma was assessed with enrichment PCR followed by next generation sequencing and standardized reporting of copies per 105 genome equivalents (GE). Results: In a prospective-retrospective study o...