ECE2018 Guided Posters Thyroid Cancer - Diagnostics & Treatments (12 abstracts)
Aim: To evaluate the effectiveness of Peptide Receptor Radionuclide Therapy with 177Lu-octreotate (PRRT) for medullary thyroid carcinoma (MTC).
Background: There are few therapeutic options for progressive metastatic MTC. The Erasmus MC Center for Neuroendocrine Tumors has been at the forefront of developing PRRT for neuroendocrine tumors. PRRT has also been suggested to be a useful treatment for MTC, but evidence is very limited.
Methods: Retrospective evaluation of results of our ten years experience with PRRT treatment in a highly selected group of MTC patients with progressive disease or refractory symptoms. In addition, a retrospective evaluation of uptake on historical 111In-DTPA-octreotide scans was performed in patients with detectable tumor load >1 cm.
Results: Over the years, ten MTC patients were treated with PRRT. Forty percent of patients (4/10) showed stable disease at first follow up (8 months after start of therapy) whereas the other six were progressive. Patients with stable disease had the combination of both a high uptake on 111In-DTPA-octreotide scan (grade ≧3; more than liver) and a clear somatostatin receptor type 2a (SSTR2a) expression on tumor by immunohistochemistry. Retrospective evaluation of historical 111In-DTPA-octreotide scans of 35 non-treated MTC patients revealed uptake less than liver (Grade 1) in the vast majority of patients 31/35 (89%) with uptake similar as liver (Grade 2) in the remaining 4/35 (11%).
Conclusions: PRRT using 177Lu-octreotate was only effective in the patients that had the combination of high uptake on 111In-DTPA-octreotide scan (>liver) and in which the pathology report showed clear SSTR2a expression. This high uptake was only present in a very limited number of patients, suggesting that this treatment can only be considered for a highly selected group of MTC patients.
19 May 2018 - 22 May 2018