Meta-analysis of mortality in patients with high-risk intraductal papillary mucinous neoplasms under observation

Background: Although consensus guidelines suggest that patients with high-risk intraductal papillary mucinous neoplasms (IPMNs) should have surgery, a non-operative strategy is often selected in patients who are poor surgical candidates. The aim was to determine the risk of disease-related death from IPMN in patients with worrisome features or high-risk stigmata who were kept under observation. Methods: A PubMed literature search was undertaken of articles published from August 1992 to June 2016 (updated October 2017). The methodology was developed from PRISMA and MOOSE checklists. Incidence proportions and rates of overall and IPMN-related deaths were calculated, with subgroup analyses for main-duct/mixed-type and branch-duct IPMNs. Quality of the studies, publication bias and heterogeneity were explored. Results: Six studies reported data on overall mortality and eight described disease-specific mortality for 556 patients during follow-up ranging from 24·9 to 60·0 months. Pooled rates of overall and IPMN-related mortality were 30·9 (95 per cent c.i. 19·6 to 45·1) and 11·6 (6·0 to 21·2) per cent respectively. The pooled incidence rate for overall mortality was substantially higher than that for IPMN-related mortality: 78 (95 per cent c.i. 44 to 111) and 23 (9 to 37) per 1000 patient-years respectively. The pooled incidence rate for disease-specific mortality was considerably lower for branch-duct than for main-duct or mixed-type IPMNs: 5 (0 to 10) and 32 (12 to 52) per 1000 patient-years respectively. Conclusion: In patients unfit for surgery, IPMN-related mortality among patients with worrisome features and high-risk stigmata is low, and the risk of death from other causes much higher.