Systematic review and meta-analysis of observational studies on BD-IPMN progression to malignancy

Abstract

Background: The vast majority of presumed branch-duct intraductal papillary mucinous neoplasms (BD-IPMN) of the pancreas are referred to a surveillance program due to the relatively low risk of malignancy. We aim to evaluate all available data of observational studies focused on BD-IPMN’s risk of progression and malignancy in order to provide vital insights on their management in clinical practice. Methods: A comprehensive research was conducted on PubMed, Cochrane, and Embase for observational studies published before January 1st, 2020. The progression of a BD-IPMN was defined as the finding of worrisome features (WF) or high-risk stigmata (HRS) during surveillance. Overall malignancy was defined as all malignancies such as malignant IPMN, concomitant PDAC, and other malignancies, including BD-IPMN with high-grade sec. Baltimore Consensus 2015 or BD-IPMN with high-grade dysplasia (carcinoma in situ) sec. WHO 2010. A meta-analysis was performed to investigate the presence of a mural nodule as a possible predictor of malignancy. Results: Twenty-four studies were included for a total of 8941 patients with a presumed BD-IPMN. The progression rate was 20.2% and 11.8% underwent surgery with a malignancy rate of 29.5% at final pathology. Of those, 78% had malignant IPMN and 22% had concomitant pancreatic cancer. Overall, 0.5% had distant metastasis. The meta-analysis showed that the risk of malignancy in presence of a mural nodule > 5mm has an OR of 11.4 (95%CI 1.802-72.106), while a non-enhancing mural nodule, or an enhancing mural nodule < 5mm has a pooled OR of 7.87 (95%CI 2.700-22.967) of harboring malignancy. Most presumed BD-IPMNs entering surveillance do not develop malignancy. Of those submitted to surgery, concomitant PDAC adds to the overall risk of detecting malignancy.