Venous invasion and lymphatic invasion are correlated with the postoperative prognosis of pancreatic neuroendocrine neoplasm

Background: To determine treatment strategies corresponding to a wide range of pancreatic neuroen-docrine neoplasms staging, easier-to-use and detailed prognostic classification is required.Methods: Patients with pancreatic neuroendocrine neoplasms who underwent curative-intent surgery at the University of Tokyo Hospital between 2000 and 2018 were retrospectively reviewed. The presence or absence of venous and lymphatic invasion was assessed. Multivariable analysis was performed to identify the risk factors of shorter overall survival and recurrence-free survival. Patients were classified into the following 3 groups: a lymphovascular invasion 0 group, whereby both venous and lymphatic invasion were negative; an lymphovascular invasion 1 group, where either of the 2 was positive; and an lym-phovascular invasion 2 group, where both were positive. The survival curves and recurrence patterns of the 3 groups were compared.Results: Eighty-nine patients were analyzed. Multivariable analysis revealed that lymphatic invasion and Ki-67 index (>= 3.0%) were independent prognostic factors of recurrence-free survival (hazard ratio: 5.2 and 3.6). Fifty-three patients were classified as lymphovascular invasion 0, 26 as lymphovascular inva-sion 1, and 10 as lymphovascular invasion 2. The recurrence-free survival curves of the 3 groups were significantly stratified (10-year recurrence-free survival: 89.1% in lymphovascular invasion 0, 57.1% in lymphovascular invasion 1, and 18.3% in lymphovascular invasion 2). Five-year cumulative liver and lymph node metastasis of lymphovascular invasion 0, lymphovascular invasion 1, and lymphovascular invasion 2 were well stratified at 0% and 3.8%, 15.8% and 23.1%, and 33.3% and 70.0%, respectively.Conclusion: Postoperative prognosis of resected pancreatic neuroendocrine neoplasms could be finely classified by venous invasion and lymphatic invasion. Management after curative-intent surgery for pancreatic neuroendocrine neoplasms may be changed by this new classification.(c) 2022 Elsevier Inc. All rights reserved.

Automated summary

A retrospective study was conducted to determine the prognostic classification of resected pancreatic neuroendocrine neoplasms based on the presence of lymphatic invasion and venous invasion. The study revealed that lymphovascular invasion is an independent prognostic factor for recurrence-free survival, and a new classification system based on lymphovascular invasion status can guide the management of these tumors after curative-intent surgery.