LAUSR

289Background: Periampullary adenocarcinomas, including pancreatic cancer, are a heterogenous group of tumors with poor prognosis. Emerging evidence indicates that tumor morphology, i.e. intestinal type (I-type) or pancreatobiliary type (PB-type), is a more relevant prognostic factor than anatomical tumor origin. The extent and clinical significance of deficient mismatch repair (dMMR) in periampullary adenocarcinoma is relatively unexplored. In this study, we examined the associations of MMR status with survival in patients with resected periampullary adenocarcinoma, with particular reference to tumor morphology and adjuvant treatment response. Methods: MMR status was assessed by immunohistochemistry on tissue microarrays with primary tumors from a retrospective consecutive cohort of 172 patients with periampullary adenocarcinoma treated with pancreaticoduodenectomy during 2001-2011 in Malmo and Lund University Hospitals, Sweden. Cox proportional hazards models were applied to calculate hazard ratios (HR)...