Distinct clinicopathological and prognostic features of insulinoma with synchronous distant metastasis

Background

The clinicopathological and prognostic features of insulinoma with synchronous metastases are unclear. This study aimed to verify the distinct clinicopathological and prognostic features of insulinoma with synchronous distant metastasis.

Methods

Patients with pancreatic neuroendocrine tumor (PanNET) were retrospectively enrolled and divided into cohort 1 (Fudan University Shanghai Cancer Center) and cohort 2 (Surveillance, Epidemiology, and End Results Program database). Both cohorts were further divided into three subgroups: insulinoma, nonfunctioning pancreatic neuroendocrine tumor (NF-PanNET), and non-insulinoma functioning pancreatic neuroendocrine tumor (NiF-PanNET).

Results

Cohorts 1 and 2 comprised 505 and 2761 patients (1566 M0 patients and 1195 M1 patients), respectively. In cohort 1 and cohort 2 M0 subgroup, insulinoma showed longer disease-free survival, overall survival (OS), and disease-specific survival (DSS) than NiF-PanNET and NF-PanNET (not reached vs. 48 and 60months, p?<?0.001; 183months vs. 87 and 109months, p?<?0.001; 247months vs. 121 and 140months, p?=?0.002). However, in cohort 2 M1, the mDSS for metastatic insulinoma was shorter than that for NiF-PanNET (31months vs. 61months, p?=?0.045), while the mDSS and mOS were similar to those for NF-PanNET. The percentage of T1 and N0 patients was similar between the metastatic insulinoma subgroup and NiF-PanNET and NF-PanNET subgroups. The Ki-67 index and recurrence had a positive linear relationship only for NiF-PanNET and NF-PanNET (p?=?0.009).

Conclusions

Insulinoma with synchronous metastasis showed clinicopathological and prognostic characteristics similar to those of NF-PanNET. Metastatic insulinoma had worse prognosis than non-insulinoma F-PanNET. These findings may help in the clinical management of metastatic insulinoma.