Dual threshold contouring for [68Ga]DOTATATE PET and correlation with overall survival (OS) in patients with neuroendocrine neoplasia (NEN)

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Introduction: Accurate contouring for [68Ga]DOTATATE PET in NEN is challenging due to differing physiological uptake for the liver, spleen and other organs. This poses a significant problem for absolute thresholding algorithms using a single threshold, even if the threshold is based on liver uptake (as suggested for FDG PET by PERCIST). Improved contouring of PET to measure [68Ga]DOTATATE-avid tumour volume could help clinical translation of this potential biomarker.

Aim(s): To propose a [68Ga]DOTATATE PET contouring algorithm with one threshold for hepatic lesions and another for extrahepatic lesions in NEN, and to investigate its prognostic significance in gastroenteropancreatic NENs (GEPNEN).

Materials and methods: Retrospective study of patients with advanced GEPNEN who underwent [68Ga]DOTATATE PET/CT imaging. A flat threshold of 4 was applied for extrahepatic lesions and threshold of (1.5SUVmean + 2SD in liver) for hepatic lesions, using a semi-automated software workflow, with nuclear medicine physician verification. The main measure was the Total Lesion Volume (TLV). Primary endpoint: OS, secondary endpoint: progression-free survival (PFS).

Conference:

Presenting Author: Chan D

Authors: Chan D, Mokhtar S, Bernard E, Diakos C, Sabahi Z,

Keywords: prognostic biomarker, PET imaging, [68Ga]DOTATATE, Total Lesion Volume,