Low Dose Multiple Cycle (LD/MT) Peptide Receptor Radionuclide Therapy: a new concept for the treatment of well-differentiated metastatic neuroendocrine tumors

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Introduction: It has been shown experimentally that low dose radiation can effectively kill slow growing cancer cells. Also, external beam radiation therapy applies a fractionated delivery of radiation dose to reduce toxicity with equal or even better therapeutic efficacy.

Aim(s): To investigate the efficacy of low dose multiple cycles (LD/MT) of peptide receptor radionuclide therapy (PRRT) in patients with well-differentiated neuroendocrine tumors.

Materials and methods: Twenty-seven patients (mean age 58.5 yrs; F:M - 13:14) with progressive, metastatic neuroendocrine tumors were treated in 2008, with low activities of Y-90 DOTA-TATE (Y-90) or Lu-177 DOTA-TATE (Lu-177) at multiple cycles. The median administered acitivity of Y-90 was 1.5 GBq and that of Lu-177 was 5.5 GBq every six weeks (maximum of four cycles) under renal protection using amino acid infusions. Response assessment was done by morphological (CT, MRT) and molecular imaging (Ga-68 DOTA-TATE PET/CT), as well as by tumor marker follow-up (CgA and serotonin). Primary tumors were located in the pancreas-14, ileum-six, lungs-two and glomus caroticum-one. Four patients had CUP syndrome.

Conference: 7th Annual ENETSConcerence (2010)

Presenting Author:

Authors: Prasad V, Roether M, Zachert C, Baum R,

Keywords: Peptide Receptor Radionuclide Therapy (PRRT), low dose multiple cycle, well-differentiated neuroendocrine tumors,