Inflammation based index and tumor heterogeneity on pretherapeutic 68Ga DOTATOC PET/CT predict outcome in midgut neuroendocrine tumor patients treated with 177Lu-oxodotreotide

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Introduction: Peptide receptor radionuclide therapy with 177Lu oxodotreotide (LuPRRT) is a standard treatment for the management of patients with inoperable metastatic well-differentiated neuroendocrine tumors of the midgut (iNET). As LuPRRT becomes widely used for a heterogeneous population of NET patients, practical predictive biomarkers are needed. Inflammation based index (IBI) derived from serum C reactive protein and albumin is associated with progression free survival (PFS) and overall survival (OS) in patients with PRRT for NETs. Ga-68 DOTATOC PET/CT (DOTAPET) assessment of lesion heterogeneity was predictive for response to PRRT.

Aim(s): We performed visual assessment of lesion heterogeneity on pretherapeutic DOTAPET as well as IBI for LuPRRT in well-differentiated grade I-II iNET patients (NCT03667092).

Materials and methods: 43 patients with grade I-II iNET received up to 4 cycles of 7.4 GBq/cycle of LuPRRT. 38 patients underwent baseline DOTAPET and baseline blood tests to assess IBI. DOTAPET-lesion heterogeneity was evaluated using Tixier’s (JNM, 2014) modified visual scale. Response: RECIST1.1 at 12 months after start of LuPRRT.

Conference:

Presenting Author: Vija L

Authors: Vija L, Dierickx L, Kanoun S, Texier J, Terroir M,

Keywords: LuPRRT, GaDOTA PET/CT, neuroendocrine tumor, outcome,