Comparison of phenotypes and outcomes following resection of incidental versus symptomatic pancreatic neuroendocrine tumors.

Background And Aim: fifty to 70 percent of pancreatic neuroendocrine tumors are diagnosed incidentally. The objective of this study was to compare the phenotype and oncological outcomes of incidental versus symptomatic pancreatic neuroendocrine tumors.

Methods: a retrospective study was performed, identifying all incidental and symptomatic tumors resected between 2000 and 2019. Baseline characteristics, symptoms, operative variables and pathological stage were all recorded. Patterns of recurrence and overall and disease-free survival were analyzed in both groups.

Results: fifty-one incidental and 45 symptomatic pancreatic tumor resections were performed. Symptomatic tumors were more frequent in females (29 vs 17; p = 0.005) and younger patients (median years; 50 vs 58; p = 0.012) and were detected at a more advanced stage (p = 0.027). There were no differences in location and most resections (n = 49; 51 %) were performed laparoscopically. There were no operative mortalities and 17 (17.7 %) severe complications (≥ IIIb on the Clavien-Dindo classification) were recorded with no differences between the two groups. With a median follow-up of 64.4 months (range 13.5-90), overall survival at five and ten years was 89.7 % and 72.8 % for the non-incidental tumors and 80.9 % and 54.6 % for the incidental tumors (p = ns), respectively. Disease-free survival in both groups (excluding M1a) was 71.2 % and 47.5 %, and 93.7 % and 78.1 %, respectively (p = ns).

Conclusions: symptomatic tumors are more frequent in females and present at more advanced pathological stages. There were no significant differences in overall and disease-free survival between the two groups. Resection of incidental tumors ≥ 1.5-2 cm seems advisable, although each case should be assessed on an individual basis.