KRAS and pancreatic ductal adenocarcinoma: The study, which enrolled 170 patients with histologically confirmed pancreatic ductal adenocarcinoma characterized by mutant KRAS and positive immunohistochemical staining of programmed death-ligand 1, divided them into two groups: one receiving stereotactic body radiotherapy, pembrolizumab, and trametinib, and the other receiving stereotactic body radiotherapy and gemcitabine.