Background : Adjuvant therapy is beneficial in prolonging survival in patients with pancreatic ductal adenocarcinoma. However, no clear guidelines are available on the oncologic effect of adjuvant therapy in resected invasive intraductal papillary mucinous neoplasms (inv-IPMN).

Methods : From 2001 to 2020, 332 patients with inv-IPMN of the pancreas were retrospectively reviewed at fifteen centers located in eight countries. Propensity score-matched analysis and stage matched survival analysis were conducted.

Results : Finally, 289 patients were enrolled in this study after exclusion (neoadjuvant therapy, unresectable disease, uncertain status of adjuvant therapy, stage IV). A total of 170 patients were enrolled in a 1:1 propensity score-matched analysis according to covariates (R status, AJCC 8th stage, lymphovascular invasion, perineural invasion). In the overall cohort, DFS was significantly better in the surgery alone (SA) group than the adjuvant therapy (AT) group (p=0.003), but OS was not (p=0.579). There was no significant difference in OS in stage-matched analysis between SA and AT groups (stage I, p=0.402; stage II, p=0.179). Adjuvant therapy did not show a survival benefit in subgroup analysis according to nodal metastasis (N0, p=0.481; N+, p=0.705). On multivariable analysis, node metastasis (HR 4.083; 95% CI 2.408-6.772, p<0.001) and CA 19-9 ≥ 100 (HR 2.058; 95% CI 1.247-3.395, p=0.005) were identified as an adverse prognostic factor in resected inv-IPMN.

Conclusions : Current strategy of adjuvant therapy may not improve the OS in patients with resected inv-IPMN. Further investigations on the potential role of adjuvant therapy in inv-IPMN are mandatory.