RT Journal Article SR Electronic T1 Peptide receptor radionuclide therapy (PRRT) for neuroendocrine tumors (NET): A two-year single institution experience JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1438 OP 1438 VO 61 IS supplement 1 A1 Duan, Heying A1 Ninatti, Gaia A1 Girod, Bradley A1 Ferri, Valentina A1 Guja, Kip A1 Song, Hong A1 Kunz, Pamela A1 Fisher, George A1 Iagaru, Andrei A1 Mari Aparici, Carina YR 2020 UL http://jnm.snmjournals.org/content/61/supplement_1/1438.abstract AB 1438Objectives: Neuroendocrine tumors (NET) are a heterogenous group of tumors, once thought rare, but now show a rising incidence. The tumor often times is indolent, thus leading to a late diagnosis at an advanced metastatic stage. Peptide receptor radionuclide therapy (PRRT) with radiolabeled somatostatin analogue has emerged as a new encouraging systemic treatment modality, especially for unresectable metastasized NETs. PRRT is not only known to reduce tumor burden but also NET-related symptoms, thus increasing quality of life. We present here our initial experience with lutetium-177 (177Lu) labeled Dotatate since FDA approval in January 2018 in patients with NET and other somatostatin receptor (SSTR) positive tumors. Methods: Sixty-three patients (33 males and 30 females; 37 - 81-year-old, mean ± SD: 62.1 ± 10.4 years) were treated with PRRT at our institution. Thereof 58 had progressing NETs (32 of the pancreas, 18 of the small intestine, 1 of the coecum, 1 of the appendix, 1 of the stomach and 5 of unknown primary), 3 had a paraganglioma, and 2 had a pheochromocytoma. Treatment was scheduled every 8 weeks for a total of 4 cycles. 68Ga-Dotatate PET/CT was performed at baseline, interim after 2 cycles, and following completion of PRRT. RECIST and SSTR density based on change of SUVmax were used to evaluate response to therapy. We assessed progression-free survival (PFS), objective response rate (ORR) and, considering the short follow-up time, an interim overall survival (OS). Results: 36/63 (57.1%) patients completed all 4 cycles of PRRT, receiving a full dose of 7400MBq each. 10/63 (15.9%) patients had to discontinue treatment (4 after 1st cycle, 3 after 2nd cycle, and 3 after 3rd cycle) due to co-morbidities. 17/63 (27%) patients are still scheduled to receive additional cycles. The 11-month PFS rate was 57% and the 14-month PFS rate was 62%. The ORR was 26%. In the interim OS analysis, 8 deaths occurred from co-morbidities. Conclusions: In our heterogenous and heavily pretreated patient cohort, the preliminary data show overall good results of PRRT with a high ORR.