Abstract 497P
Background
Importance of venous and lymphatic invasion, respectively, of pancreatic neuroendocrine neoplasm (pNEN) have rarely been discussed.
Methods
Patients with pNEN undergoing curative-intent surgery between 2000 and 2018 in a tertiary institution were included. Patients with distant metastases were excluded. Clinicopathologic findings of the patients were retrospectively analyzed. Venous and lymphatic invasions were independently assessed. Patients were classified into 3 groups according to lymphovascular invasion (LVI): LVI 1, both were negative; LVI 2, either of the two was positive; LVI 3, both two were positive.
Results
A total of 89 patients were included in the study. Multivariable analysis of overall survival (OS) identified lymph node metastasis as an independent prognostic factor (hazard ratio; 2.7, P=0.04). Multivariable analysis of recurrence free survival (RFS) identified lymphatic invasion and Ki67 index (≥ 3.0%) as independent prognostic factors (Hazard ratio; 5.2 and 3.6, P=0.001 and 0.008, respectively). The 10-year OS in LVI 0 (n=53), LVI 1 (n=26), and LVI 2 (n=10) were 91%, 87%, and 36%, respectively, of which the former 2 groups were similar (P=0.68) whereas the latter 2 groups were significantly different (P=0.05). The 10-year RFS of the 3 groups were 89%, 57%, and 18%, respectively, of which the difference were significant (P=0.01 and 0.03). The 5-year cumulative rates of liver recurrence were 0%, 16%, and 33%, respectively, of which the former 2 groups were significantly different (P<0.01) and the latter 2 groups were not significantly different (P=0.11). The 5-year cumulative rates of lymph node recurrence were 4%, 23%, and 70%, respectively, of which the difference were significant (P<0.01 and P<0.01, respectively).
Conclusions
Venous and lymphatic invasions independently impact postoperative recurrence of pNEN. The management after curative-intent surgery for pNEN may be changed according to these findings.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.