Correlation of Autoimmune Pancreatitis and Malignancy: Systematic Review and Meta-Analysis.

There is conflicting evidence regarding autoimmune pancreatitis (AIP) association with pancreatic and non-pancreatic cancers. Literature lacks data on overall prevalence of malignancies in autoimmune pancreatitis. Given the lack of definite evidence, we aimed to pool and summarize data from available literature regarding prevalence of different malignancies in AIP. We conducted a systematic search of MEDLINE, EMBASE, Cochrane Register of Controlled Trials, and Web of Science through February 16, 2021, to include observational studies assessing the incidence of cancer in AIP. We used the DerSimonian–Laird method with random effects for meta-analysis. Pooled prevalence, 95% confidence interval (CI), and I2 statistic are reported. A total of 17 studies with 2746 patients were included assessing the prevalence of cancer in AIP. The overall prevalence of cancer in AIP was 9.6% [95% confidence interval (CI), 5.7–13.5%]. The cancers with the highest prevalence in AIP population were gastric and colorectal cancer, with prevalence of 1.3% (95% CI, 0.5–2.1%) and 1.2% (95% CI, 0.6–1.8%), respectively. We demonstrate the prevalence of different cancers in AIP. Inflammatory surge in AIP and subsequent carcinogenesis is one explanation for this association. Moreover, AIP can be a paraneoplastic syndrome manifestation of malignancies.