Impact of adjuvant therapy in patients with invasive intraductal papillary mucinous neoplasms of the pancreas: an international multicenter cohort study

Background: Adjuvant therapy prolongs survival in patients with pancreatic ductal adenocarcinoma. However, no clear guidelines are available regarding the oncologic effects of adjuvant therapy (AT) in resected invasive intraductal papillary mucinous neoplasms (IPMN). The aim was to investigate the potential role of AT in patients with resected invasive IPMN.Materials and methods: From 2001 to 2020, 332 patients with invasive pancreatic IPMN were retrospectively reviewed in 15 centres in eight countries. Propensity score-matched and stage-matched survival analyses were conducted.Results: A total of 289 patients were enroled in the study after exclusion (neoadjuvant therapy, unresectable disease, uncertain AT status, and stage IV). A total of 170 patients were enroled in a 1:1 propensity score-matched analysis according to the covariates. In the overall cohort, disease-free survival was significantly better in the surgery alone group than in the AT group (P=0.003), but overall survival (OS) was not (P=0.579). There were no significant differences in OS in the stage-matched analysis between the surgery alone and AT groups (stage I, P=0.402; stage II, P=0.179). AT did not show a survival benefit in the subgroup analysis according to nodal metastasis (N0, P=0.481; N+, P=0.705). In multivariate analysis, node metastasis (hazard ratio, 4.083; 95% CI, 2.408-6.772, P<0.001), and cancer antigen 19-9 greater than or equal to 100 (hazard ratio, 2.058; 95% CI, 1.247-3.395, P=0.005) were identified as adverse prognostic factors in resected invasive IPMN.Conclusion: The current AT strategy may not be recommended to be performed with resected invasive IPMN in stage I and II groups, unlike pancreatic ductal adenocarcinoma. Further investigations of the potential role of AT in invasive IPMN are recommended.