Risk of Cancer in Patients With Autoimmune Pancreatitis

RESULTS: Of the 108 AIP patients, 18 cancers were found in 15 patients (13.9 % ) during the median follow-up period of 3.3 years. The SIR of cancer was 2.7 (95 % confi dence interval (CI) 1.4 - 3.9), which was stratifi ed into the fi rst year (6.1 (95 % CI 2.3 - 9.9)) and subsequent years (1.5 (95 % CI 0.3 - 2.8)) after AIP diagnosis. Relative risk of cancer among AIP patients at the time of AIP diagnosis was 4.9 (95 % CI 1.7 - 14.9). In six of eight patients whose cancer lesions could be assessed before cortico- steroid therapy for AIP, abundant IgG4-positive plasma cell infi ltration was observed in the cancer stroma. These six patients experienced no AIP relapse after successful cancer treatment. CONCLUSIONS: Patients with AIP are at high risk of having various cancers. The highest risk for cancer in the fi rst year after AIP diagnosis and absence of AIP relapse after successful treatment of the coexisting cancers suggest that AIP may develop as a paraneoplastic syndrome in some patients. SUPPLEMENTARY MATERIAL is linked to the online version of the paper at http://www.nature.com/ajg