Relationship between absorbed dose and response in neuroendocrine tumors treated with [177Lu]Lu-DOTA-TATE

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Introduction: Peptide receptor radionuclide therapy (PRRT) presents the possibility of tracing and quantifying the uptake of the drug in the body and performing dosimetry, potentially allowing individualization of treatment schemes. However, the details of how neuroendocrine tumors (NETs) respond to different absorbed doses are insufficiently known.

Aim(s): To investigate the relationship between tumor absorbed dose and tumor response in a cohort of patients with NETs treated with [177Lu]Lu-DOTA-TATE.

Materials and methods: This is a retrospective study based on 69 tumors in 32 patients treated within a clinical trial. Dosimetry was performed at each cycle of [177Lu]Lu-DOTA-TATE.. Hybrid planar-SPECT/CT imaging was used, including quantitative SPECT reconstruction, voxel-based absorbed-dose-rate calculation, semiautomatic image segmentation, and partial-volume correction. Changes in tumor volume was used to determine tumor response. The volume for each tumor was manually delineated in consecutive CT-scans. Tumors were stratified according to grade. The relationship between absorbed dose and response was investigated using mixed-effects models and logistic regression. Tumors below 4 cm3 were excluded.

Conference:

Presenting Author: Warfvinge C

Authors: Warfvinge C, Gustafsson J, Roth D, Tennvall J, Svensson J,

Keywords: PRRT, Neuroendocrine tumor, dose-response, dosimetry,