KRAS gene mutation quantification in the resection or venous margins of pancreatic ductal adenocarcinoma is not predictive of disease recurrence

Abstract Pancreatic ductal adenocarcinoma (PDAC) patients eligible for curative surgery undergo unpredictable disease relapse. Even patients with good pathological response after neo-adjuvant treatment (NAT) remain susceptible to recurrent PDAC. Molecular analysis of R0 margins may identify patients with worse prognosis. Retrospective analysis of patients, either eligible for up-font surgery (UFS) or resected patients who underwent NAT with good pathological responses, collected survivals post-surgery and examined the molecular status of mutant KRAS by droplet digital PCR. Expectedly, KRAS mutant allele frequencies (MAF) were higher in UFS than in NAT tumor tissues or remnants, and in the ypT1 than the ypT0 tumors in the NAT group. Mutant KRAS positivity or MAFs in margins did not identify patients with detectable pathological disease in the NAT group, nor was it predictive of shorter recurrence-free or overall survival within or between groups. KRAS-double positivity in both venous and tumor resection margins did not identify patients with worse prognosis, regardless of the groups. The cohorts ‘sizes were small due to limited numbers of patients meeting the inclusion criteria, but KRAS-positivity or MAFs in resection and venous margins did not carry prognostic value. Comparison of margins from good versus bad responders receiving NAT may provide better clinical value.