IgG4‐related pancreatobiliary diseases could be associated with onset of pancreatobiliary cancer: A multicenter cohort study

Background The risk and prognosis of pancreatobiliary cancer and in patients with autoimmune pancreatitis (AIP) and IgG4‐related sclerosing cholangitis (IgG4‐SC) remain unclear. Therefore, we retrospectively investigated the risk of pancreatobiliary cancer and prognosis in patients with AIP and IgG4‐SC. Methods Patients with AIP and IgG4‐SC at seven centers between 1998 and 2022 were investigated. The following data were evaluated: (1) the number of cancers diagnosed and standardized incidence ratio (SIR) for pancreatobiliary and other cancers during the observational period and (2) prognosis after diagnosis of AIP and IgG4‐SC using standardized mortality ratio (SMR). Results This study included 201 patients with AIP and IgG4‐SC. The mean follow‐up period was 5.7 years. Seven cases of pancreatic cancer were diagnosed, and the SIR was 8.11 (95% confidence interval [CI]: 7.29–9.13). Three cases of bile duct cancer were diagnosed, and the SIR was 6.89 (95% CI: 6.20–7.75). The SMR after the diagnosis of AIP and IgG4‐SC in cases that developed pancreatobiliary cancer were 4.03 (95% CI: 2.83–6.99). Conclusions Patients with autoimmune pancreatitis and IgG4‐SC were associated with a high risk of pancreatic and bile duct cancer. Patients with AIP and IgG4‐SC have a worse prognosis when they develop pancreatobiliary cancer. Kurita and colleagues found that autoimmune pancreatitis and IgG4‐related sclerosing cholangitis were associated with a high risk of pancreatic and bile duct cancer. Surveillance for pancreatobiliary cancer development is recommended after the diagnosis of autoimmune pancreatitis and IgG4‐related sclerosing cholangitis, as pancreatic and bile duct cancer significantly worsen the prognosis.