M Ö Öksüz1, L Winter2, C Pfannenberg3, G Reischl4, K Müssig5, R Bares6, H Dittmann6. 1. Département d'Imagerie Médicale, Hôpital neuchâtelois, Maladière 45, 2000 Neuchâtel, Switzerland; Department of Nuclear Medicine, Tübingen University Hospital, Otfried-Müller-Strasse 14, 72076 Tübingen, Germany. Electronic address: mehmet-ozer.oksuz@ne.ch. 2. Department of Radiology and Nuclear Medicine, Basel University Hospital, Petersgraben 4, 4031 Basel, Switzerland. 3. Department of Radiology, Tübingen University Hospital, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany. 4. Department of Radiopharmacy, Tübingen University Hospital, Röntgenweg 15, 72076 Tübingen, Germany. 5. Deutsches Diabetes-Zentrum (DDZ), Leibniz-Zentrum für Diabetes-Forschung an der Heinrich-Heine-Universität Düsseldorf, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany. 6. Department of Nuclear Medicine, Tübingen University Hospital, Otfried-Müller-Strasse 14, 72076 Tübingen, Germany.
Abstract
PURPOSE: PET with (68)Ga-DOTATOC allows for imaging and quantitative assessment of somatostatin receptor expression in neuroendocrine tumors (NET). The aim of this retrospective study was to analyze whether pre-therapeutic (68)Ga-DOTATOC PET/CT is able to predict response to Peptide Receptor Radionuclide Therapy (PRRT). PATIENTS AND METHODS: Forty patients with advanced stage NET were treated with a fixed dose of (90)Y-DOTATOC (5550 or 3700MBq). Prior to PRRT, each patient received (68)Ga-DOTATOC PET/CT. Treatment results were evaluated after 3months by CT, tumor marker levels and clinical course and correlated with (68)Ga-DOTATOC uptake (SUVmax) and the assumed uptake of (90)Y-DOTATOC in tumor manifestations (MBq/g). ROC analysis and pairwise comparison of area under the curve (AUC) were performed with pre-treatment uptake of (68)Ga-DOTATOC, assumed uptake of (90)Y-DOTATOC and treatment activity alone and in relation to body weight as continuous variables, and response/no response as classification variable. RESULTS: According to conventional criteria (tumor shrinkage, decrease of tumor markers, improved or stable clinical condition), 20 patients were classified as responders, 16 as non-responders and in four patients findings were equivocal. Using a SUV more than 17.9 as cut-off for favorable outcome, PET was able to predict treatment response of all responders and 15 out of 16 non-responders. All four patients with equivocal findings showed SUV less than or equal to 17.9 and soon experienced tumor progression. The assumed uptake of (90)Y-DOTATOC in tumor manifestations using a cut-off more than 1.26MBq/g as predictor of response was able to correctly classify 19 out of 20 responders, and 14 out of 16 non-responders. In all patients with equivocal findings, the assumed uptake of (90)Y-DOTATOC was below 1.26MBq/g. CONCLUSION: Pre-therapeutic (68)Ga-DOTATOC tumor uptake as well as assumed uptake of (90)Y-DOTATOC are strongly associated with the results of subsequent PRRT. The defined cut-off values should be confirmed by prospective studies and may then provide the rationale for individual dosing and selecting patients with high likelihood of favorable treatment outcome.
PURPOSE: PET with (68)Ga-DOTATOC allows for imaging and quantitative assessment of somatostatin receptor expression in neuroendocrine tumors (NET). The aim of this retrospective study was to analyze whether pre-therapeutic (68)Ga-DOTATOC PET/CT is able to predict response to Peptide Receptor Radionuclide Therapy (PRRT). PATIENTS AND METHODS: Forty patients with advanced stage NET were treated with a fixed dose of (90)Y-DOTATOC (5550 or 3700MBq). Prior to PRRT, each patient received (68)Ga-DOTATOC PET/CT. Treatment results were evaluated after 3months by CT, tumor marker levels and clinical course and correlated with (68)Ga-DOTATOC uptake (SUVmax) and the assumed uptake of (90)Y-DOTATOC in tumor manifestations (MBq/g). ROC analysis and pairwise comparison of area under the curve (AUC) were performed with pre-treatment uptake of (68)Ga-DOTATOC, assumed uptake of (90)Y-DOTATOC and treatment activity alone and in relation to body weight as continuous variables, and response/no response as classification variable. RESULTS: According to conventional criteria (tumor shrinkage, decrease of tumor markers, improved or stable clinical condition), 20 patients were classified as responders, 16 as non-responders and in four patients findings were equivocal. Using a SUV more than 17.9 as cut-off for favorable outcome, PET was able to predict treatment response of all responders and 15 out of 16 non-responders. All four patients with equivocal findings showed SUV less than or equal to 17.9 and soon experienced tumor progression. The assumed uptake of (90)Y-DOTATOC in tumor manifestations using a cut-off more than 1.26MBq/g as predictor of response was able to correctly classify 19 out of 20 responders, and 14 out of 16 non-responders. In all patients with equivocal findings, the assumed uptake of (90)Y-DOTATOC was below 1.26MBq/g. CONCLUSION: Pre-therapeutic (68)Ga-DOTATOC tumor uptake as well as assumed uptake of (90)Y-DOTATOC are strongly associated with the results of subsequent PRRT. The defined cut-off values should be confirmed by prospective studies and may then provide the rationale for individual dosing and selecting patients with high likelihood of favorable treatment outcome.
Authors: Manuel Weber; Lukas Kessler; Benedikt Schaarschmidt; Wolfgang Peter Fendler; Harald Lahner; Gerald Antoch; Lale Umutlu; Ken Herrmann; Christoph Rischpler Journal: BMC Cancer Date: 2020-04-16 Impact factor: 4.430
Authors: Lisa Bodei; Mark S Kidd; Aviral Singh; Wouter A van der Zwan; Stefano Severi; Ignat A Drozdov; Jaroslaw Cwikla; Richard P Baum; Dik J Kwekkeboom; Giovanni Paganelli; Eric P Krenning; Irvin M Modlin Journal: Eur J Nucl Med Mol Imaging Date: 2018-02-26 Impact factor: 9.236
Authors: Lisa Bodei; Mark S Kidd; Aviral Singh; Wouter A van der Zwan; Stefano Severi; Ignat A Drozdov; Anna Malczewska; Richard P Baum; Dik J Kwekkeboom; Giovanni Paganelli; Eric P Krenning; Irvin M Modlin Journal: Eur J Nucl Med Mol Imaging Date: 2019-12-14 Impact factor: 9.236