The five periampullary cancers: Not just different siblings but different families—An international multicenter cohort study.

Abstract

4167 Background: Cancer arising in the periampullary region can be anatomically classified in pancreatic ductal adenocarcinoma (PDAC), distal cholangiocarcinoma (dCCA), duodenal adenocarcinoma (DAC) and ampullary adenocarcinoma (AAC). Based on histopathology, the AAC is currently subdivided in the intestinal (AmpIT) and pancreatobiliary (AmpPB) subtype. Despite close anatomical resemblance, it is unclear how the ampullary subtypes relate to the remaining periampullary cancers in tumor characteristics and behavior. Methods: This is an international multicenter cohort study, including patients after curative intent resection for periampullary cancer retrieved from 45 centers (from Europe, USA, Asia and Canada) between 2010 and 2021. Pre-operative CA19-9, differences in pathology and postoperative pancreatic fistula (POPF, grade B/C), 8-year overall survival (OS) and disease-free interval (DFI) were compared between DAC, AmpIT, AmpPB, dCCA and PDAC. Results: Overall, 3809 patients were included of which 348 DAC, 774 AmpIT, 848 AmpPB, 1036 dCCA and 803 PDAC. The best 8-years overall survival was found in patients with AmpIT and DAC (49.8% and 47.9%), followed by AmpPB (34.9%, p<0.001), dCCA (26.4%, p=0.020) and last, PDAC (12.9%, P<0.001). The best 8-years DFI was measured for AmpIT (62.7%) and the worst for both dCCA and PDAC (24.9% and 21.8%). This pattern correlated with the height of the pre-operative CA19-9 but not with the pathology, in which the largest and most progressed tumors were found in DAC. The incidence of POPF was lower in the pancreas-related tumor types (AmpPB 18.5%, PDAC 8.3%) compared to the non-pancreas related types (DAC 27.3%, AmpIT 25.5%, dCCA 27.6%). Conclusions: Despite the close anatomic relation of the five periampullary cancers, this study shows that there are prognostic and clinically relevant differences in terms of preoperative blood markers, pathology, complications, long-term survival, and recurrence. More characteristics are shared between DAC and AmpIT and between AmpPB and dCCA than between the two ampullary subtypes. Instead of using collective definitions for “periampullary cancers”, this study emphasizes the need for individual evaluation of each histopathological periampullary subtype with the ampullary subtypes as individual entities in future studies.