Although simultaneous occurrences of autoimmune pancreatitis (AIP) and cancer are occasionally observed, it remains largely unknown whether cancer and AIP occur independently or these disorders are interrelated. The aim of this study was to examine the relationship between AIP and cancer.
We conducted a multicenter, retrospective cohort study. One hundred and eight patients who met the Asian diagnostic criteria for AIP were included in the study. We calculated the proportion, standardized incidence ratio (SIR), relative risk, and time course of cancer development in patients with AIP. We also analyzed the clinicopathological characteristics of AIP patients with cancer in comparison with those without cancer.
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% confidence interval (CI) 1.4–3.9), which was stratified into the first 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 corticosteroid therapy for AIP, abundant IgG4-positive plasma cell infiltration was observed in the cancer stroma. These six patients experienced no AIP relapse after successful cancer treatment.
Patients with AIP are at high risk of having various cancers. The highest risk for cancer in the first 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.
1 Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
2 Translational Research Center, Kyoto University Hospital, Kyoto, Japan
3 Department of Gastroenterology and Hepatology, Japanese Red Cross Otsu Hospital, Otsu, Japan
4 Department of Gastroenterology and Hepatology, Nishikobe Medical Center, Kobe, Japan
5 Department of Gastroenterology and Hepatology, Japanese Red Cross Wakayama Medical Center, Wakayama, Japan
6 Department of Digestive Disease Center, Kitano Hospital, Osaka, Japan
7 Department of Gastroenterology and Hepatology, Shizuoka General Hospital, Shizuoka, Japan
8 Department of Gastroenterology and Hepatology, Osaka Red Cross Hospital, Osaka, Japan
9 Department of Gastroenterology and Hepatology, Kobe City Medical Center General Hospital, Kobe, Japan
10 Department of Gastroenterology and Hepatology, Tenri Hospital, Tenri, Japan
11 Department of Gastroenterology and Hepatology, Kyoto Katsura Hospital, Kyoto, Japan
12 Kyoto Industrial Health Association, Kyoto, Japan
13 Division of Radiology/Gastroenterology and Hepatology, Mayo clinic, Rochester, Minnesota, USA
14 Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan
Correspondence: Yuzo Kodama, MD, PhD, Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, 54 Shogoin-kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan. E-mail: email@example.com
SUPPLEMENTARY MATERIAL accompanies this paper at http://links.lww.com/AJG/A717
Received 23 April 2012; accepted 18 December 2012
published online 15 January 2013