Post FDA approval analysis of 200 gallium-68 DOTATATE imaging: A retrospective analysis in neuroendocrine tumor patients

Abstract

Gallium-68 DOTATATE provides physiologic imaging and assists in disease localization for somatostatin receptor (SSTR) positive neuroendocrine tumor (NET) patients. However, questions regarding usefulness of gallium-68 DOTATATE imaging in identifying the primary site in neuroendocrine tumors (NETS) of unknown primary, correlation of NET grade with median Standardized Uptake Value (SUV) and effects of long acting somatostatin analog on gallium-68 DOTATATE imaging quality needs to be evaluated. A single institution retrospective review of the first 200 NET patients with gallium-68 DOTATATE imaging from Dec 2016 to Dec 2017 was conducted. Questions related to NETs of unknown primary, correlation of Standardized Uptake Value (SUV) to Ki-67 (which signifies proliferation rate), the effects of long-acting systemic somatostatin analog (SSA) on SUV were part of our data analysis. From these 200 patients, 59.5% (119) were females, 40.5% (81) were males; the median age was 62 years. The following primary tumor sites were identified: small bowel-37.5%; pancreas-18.5%; bronchial-14%; colon-3.5%; rectum-2%; appendix-1.5%; adrenal-0.5%; prostate-0.5%; others-3% and unknown primary-19%. Mean hepatic SUV of the lesion with the greatest radiolabeled uptake in 96 patients was similar irrespective to exposure to long acting SSA. Patients exposed to long acting SSA had mean SUV of 31.3 vs 27.8 for SSA naïve patients. The difference was not statistically significant. Gallium-68 DOTATATE imaging seems to distinguished G3 NET from G1/G2 based on mean SUV, and also identified the primary tumor site in 17 of 38 (45%) patients with unknown primary. Systemic exposure to long acting SSA does not appear to influence mean SUV of gallium-68 DOTATATE scan.

Peptide-Based Agents for Cancer Treatment: Current Applications and Future Directions

“…For example, peptides targeting somatostatin receptors (SSTR), the prostate-specific membrane antigen (PSMA), integrins, chemokines, urokinase-type plasminogen activator receptors (uPAR), and cholecystokinin receptors (CCK2-R) serve as notable examples [ 253 , 254 , 255 , 256 , 257 , 258 ]. Among them, Netspot ( 68 Ga-DOTATATE) (Novartis) [ 180 , 181 ], Edotreotide gallium ( 68 Ga-DOTATOC) (ITM Radiopharma, München, Germany) [ 182 , 259 ], and Detectnet ( 64 Cu-DOTATATE) (Radio-Medix, Houston, TX, USA) [ 183 , 184 ] target SSTR and approved by FDA for PET in 2016, 2019, and 2020, respectively. Gallium gozetotide (Locametz, Illuccix, 68 Ga-PSMA-11) (Novartis) [ 185 , 186 , 187 ] and Pylarify (piflufolastat F18, 18 F-DCFPyL) (Lantheus, Billerica, MA, USA) [ 188 , 189 , 260 , 261 , 262 ] targets PSMA and is approved by FDA in 2020 and 2022, respectively.…”

Characteristics and treatment results of patients with gastroenteropancreatic neuroendocrine tumors in a tertiary care centre

“…Ga-PET has been shown to be sensitive imaging to identify somatostatin receptor-positive NET and helps in staging and primary tumor site localization for NET of unknown primary [19]. Furthermore, Ga-PET seems to distinguish G3 from G1/2 by assessing the mean standardized uptake value (SUV) [19].…”

PET-CT in Clinical Adult Oncology—VI. Primary Cutaneous Cancer, Sarcomas and Neuroendocrine Tumors

“…Gallium-68 is a generator-produced positron emitter with a short half-life of 68 min compared to 2.8 days for In-111. This enables on-site, as-needed availability of the radiotracer and a lower radiation dose for the patient compared to In-111, with an effective dose of 2.1 mSv for a 100 MBq administration [ 109 , 110 ]. Ga-68 is chelated to a variety of somatostatin analogs by means of the organic compound 1,4,7,10-tet- raazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), resulting in higher-affinity radiopharmaceuticals that are typically abbreviated as DOTA-TATE (GaTate), DOTA-TOC (GaToc) and DOTA-NOC (GaNoc) [ 111 ].…”