# [68Ga]-DOTATOC PET/CT Volumetric Parameters Reflect Metastatic Potential in Pancreatic Neuroendocrine Tumors

## TL;DR

This study shows that [68Ga]-DOTATOC PET/CT can predict metastasis risk in pancreatic neuroendocrine tumors based on tumor volume and metabolic activity.

## Contribution

The study demonstrates that volumetric PET/CT parameters correlate with metastatic potential in well-differentiated pancreatic neuroendocrine tumors.

## Key findings

- Larger metabolically active tumors showed a higher incidence of metastasis.
- Somatostatin receptor-expressing tumor volume and total lesion expression strongly correlate with metastasis (p < 0.001).
- The findings may improve treatment decisions for patients with pancreatic neuroendocrine tumors.

## Abstract

Determining the risk of metastasis in pancreatic neuroendocrine tumors is critical for guiding the most appropriate therapeutic approach. [68Ga]-DOTATOC PET/CT is a valuable technique for identifying pancreatic neuroendocrine tumors overexpressing somatostatin receptors and may provide insights into the biological behavior of pancreatic neuroendocrine tumors. We aimed to evaluate [68Ga]-DOTATOC uptake in well-differentiated pancreatic neuroendocrine tumors and determined its predictive capability for metastasis. Data from 48 patients with well-differentiated, non-functional pancreatic neuroendocrine tumors without accompanying genetic syndromes were analysed. A higher incidence of metastasis was observed in larger metabolically active tumors. Our findings may help clinicians make more precise treatment decisions, ultimately benefiting patients with pancreatic neuroendocrine tumors.

Background: [68Ga]-DOTATOC PET/CT is a valuable technique for identifying neuroendocrine tumors overexpressing somatostatin receptors; however, its diagnostic and prognostic utility for WHO low-grade pancreatic neuroendocrine tumors remains unclear. Therefore, we aimed to evaluate [68Ga]-DOTATOC uptake in well-differentiated pancreatic neuroendocrine tumors and determine its predictive capability for metastasis. Methods: Patients with pathologically diagnosed well-differentiated, non-functional pancreatic neuroendocrine tumors who underwent [68Ga]-DOTATOC PET/CT between 2015 and 2021 were included. Medical records and [68Ga]-DOTATOC PET/CT indices (maximal and mean standardized uptake values, somatostatin receptor-expressing tumor volume, and total lesion somatostatin receptor expression in pancreatic tumors) were retrospectively reviewed. Correlations between indices were analyzed to determine their collective diagnostic significance. Results: Among 93 patients who were pathologically diagnosed with pancreatic neuroendocrine tumors and underwent [68Ga]-DOTATOC PET/CT, 48 with well-differentiated, non-functional pancreatic neuroendocrine tumors without accompanying genetic syndromes were included. The pancreatic neuroendocrine tumors were classified as WHO grade 1 (n = 30, 62.5%) and grade 2 (n = 18, 37.5%), with tumors in 25% of the patients exhibiting initial metastases. A higher incidence of metastasis was observed in larger metabolically active tumors (somatostatin receptor-expressing tumor volume, p < 0.001; total lesion somatostatin receptor expression, p < 0.001). Conclusions: Volumetric parameters derived from [68Ga]-DOTATOC PET/CT correlates with initial metastasis in well-differentiated pancreatic neuroendocrine tumors.