Development of Pancreatic Adenocarcinoma in Autoimmune Pancreatitis: A Systematic Review

Abstract

Introduction: Presentation of autoimmune pancreatitis (AIP) can be similar to pancreatic adenocarcinoma (PAC) with a pancreatic mass that may cause obstructive jaundice. Chronic pancreatitis predisposes patients to PAC. The relationship between AIP and PAC is unknown. The aim of this systematic review is to determine the frequency of incident PAC in AIP, and secondarily to assess for prevalent PAC and AIP. Methods: A systematic search using PubMed, Embase, Scopus & Cochrane was performed. Search criteria included “autoimmune pancreatitis,” “pancreatic cancer,” “adenocarcinoma,” & “carcinoma” with all permutations. AIP was defined by international guidelines. Our inclusion criterion for incident PAC cases was a minimum of 1 year between AIP and PAC diagnoses to exclude prevalent cancers. The inclusion criterion for prevalent PAC cases was defined by presence of AIP and PAC within 1 year. The search yielded 636 results reviewed by 2 authors. 8 case reports and 4 retrospective studies with a total of 19 patients were included in the combined analyses. Results: There were 7 cases of incident PAC, with 4/7 (57.1%) men, mean age 67±14.1yrs (Range 39-80yrs) (Table 1). Mean time from AIP to PAC diagnosis was 78.1±60.9months (Range 12-186 months). 6/7 (85.7%) patients received prednisone therapy for AIP. 12 total cases of prevalent PAC with AIP were identified, all of which were men, mean age 61.4±5yrs (Range 53-70yrs) (Table 2). All prevalent cases of PAC with AIP were diagnosed simultaneously, with pathologic confirmation of both entities present on histology in 11/12 cases. Medical treatment of AIP was not reported for any prevalent PAC cases. Stage of PAC at diagnosis when reported was similar between incident & prevalent cases with most cases being unresectable (60% vs. 66.7%). Conclusion: Development of PAC in underlying AIP is exceedingly rare with only 7 total incident cases reported in the literature. The absolute risk remains unknown and was unable to be calculated based on included study types in this analysis. The number of prevalent cases of PAC concomitantly diagnosed with AIP should prompt a comprehensive investigation to exclude the presence of underlying malignancy and should be performed in cases of newly diagnosed AIP. Further prospective studies are warranted to determine overall risk of PAC in AIP.2733_A Figure 1. Study Characteristics of Autoimmune Pancreatitis Patients who Developed Incident Pancreatic Adenocarcinoma2733_B Figure 2. Study Characteristics of Autoimmune Pancreatitis Patients who had Prevalent Pancreatic Adenocarcinoma