Endocrine Abstracts

Introduction: Pancreatic neuroendocrine tumors (pNETs) are a heterogeneous group with various treatment options depending on grading, staging, and presence of symptoms related to hormonal secretion. Their incidence significantly increased over the past decade and nowadays constitutes 30% of all NETs of the gastrointestinal tract. Despite the evidence of a different malignancy potential of PNETs G2, postoperative management is the same in all patients.

Aim: The purpose of the study was to determine possible predictors of postoperative tumor recurrence in patients with nonfunctional pNET G2.

Materials and methods: We identified 165 patients diagnosed with pancreatic neuroendocrine tumors. 47 of them with locally advanced or metastatic pNET G2 were included in the study.

Results: Relapse occurred in 37.93% of patients operated with intention to treat, with the mean time to progression equaling about 2 years. In this group based on preoperative CT examinations, the average largest dimension of the tumor was estimated to be over twice bigger in comparison to patients with no recurrence (46.71 mm vs 22.89 mm), which was confirmed by postoperative histopathological examination (53.83 mm vs 34.36 mm). In over 80% of patients with the disease relapse, the average largest dimension of tumor equaled 25 mm or more, whereas in the group without relapse only 55.65% of patients had lesions of this size. Ki-67 varies significantly (metastatic 8.8% vs disease recurrence 6.78% vs no recurrence 5.15%). Both progression and recurrence were associated with the primary location of the tumor in the pancreatic tail. Interestingly, about 50% of patients were symptomatic in all three groups.

Conclusions: Based on the analyzed material it seems that lesions with the largest dimension equaling 25 mm or more and a higher Ki-67 may be a predictor of the disease recurrence. Patients’ complaints, important for the management of disease, seem to be unrelated to the possible PNET G2 relapse. The unequivocal confirmation of these findings requires further observation.