Association between pancreatic intraductal papillary mucinous neoplasms and extrapancreatic malignancies: A systematic review with meta-analysis

Background: It is unclear whether patients with intraductal papillary mucinous neoplasia harbor a higher risk of developing extrapancreatic malignancies. Aims: We performed a pooled estimate of the incidence of extrapancreatic malignancies in patients with intraductal papillary mucinous neoplasia, with a particular focus on the comparison to the general population. Methods: Computerized bibliographic search of main databases was performed through February 2021. The primary endpoint was the pooled incidence of extrapancreatic malignancies in patients with intraductal papillary mucinous neoplasms. Additional outcome was the comparison between intraductal papillary mucinous neoplasia patients and the general population, expressed in terms of standardized incidence ratio along with 95% confidence intervals. Results: Eighteen studies with 8709 patients were included. The pooled rate of metachronous extrapancreatic malignancies was 10 (6–13)/1000 persons-year. No difference was observed according to intraductal papillary mucinous neoplasia histology and sex, whereas a significantly superior incidence of extrapancreatic malignancies was observed in patients with main-duct (36.7%, 25.4%–48%) as compared to branch-duct intraductal papillary mucinous neoplasia (26.2%, 17.6%–34.8%; p = 0.03). Pooled standardized incidence ratio comparing expected rates in the general population was 1.01 (0.79–1.29); no difference was observed concerning rates of metachronous gastric cancer (standardized incidence ratio 1.60, 0.72–3.54) and colorectal cancer (1.29, 0.92–1.18), whereas biliary cancer was observed more frequently in intraductal papillary mucinous neoplasia patients (2.29, 1.07–4.93). Conclusion: Patients with intraductal papillary mucinous neoplasia harbor an overall rate of extrapancreatic malignancies as high as 27.3%. The rate of metachronous extrapancreatic malignancies is not superior to the general population.