68Ga-DOTATATE Positron Emission Tomography-Computed Tomography Quantification Predicts Response to Somatostatin Analog Therapy in Gastroenteropancreatic Neuroendocrine Tumors

Abstract

Background. Somatostatin analogs (SSAs) are the frontline antitumor therapy in advanced well-differentiated gastroenteropancreatic neuroendocrine tumors (GEP-NETs). A subset of patients demonstrate early disease progression on SSA therapy, yet the currently known predictors for treatment failure lack specificity to affect therapeutic decision. SSAs target tumor somatostatin receptors, the level of which can be quantitatively assessed with 68 Ga-DOTATATE positron emission tomography-computed tomography (PET/CT). We investigated the ability of 68 Ga-DOTATATE PET/CT to predict response to SSA therapy. Materials and Methods. The records of 108 consecutive patients with well-differentiated grade 1-2 GEP-NETs on SSA monotherapy who received 68 Ga-DOTATATE PET/CT scans were retrospectively reviewed to obtain baseline characteristics, 68 Ga-DOTATATE maximum standardized uptake value (SUVmax), and progression-free survival (PFS) data. The optimal SUVmax cutoff for patient stratification was obtained with receiver operating characteristic curve analysis. PFS in the high versus low SUVmax groups was compared with Kaplan-Meier survival analysis. The effects of baseline characteristics and SUVmax on PFS were examined with univariate and multivariate Cox regression. Results. 68 Ga-DOTATATE SUVmax predicted therapeutic failure with sensitivity and specificity of 39% and 98%, respectively. SUVmax of <18.35 was associated with shorter PFS, which was reproduced in the subgroup analysis of SSAnaive patients. Low SUVmax was the only predictor of early treatment failure (hazard ratio, 6.85) in multivariate analysis, as well as in the subgroup analysis of grade 2 GEP-NETs. Conclusion. Low SUVmax on 68 Ga-DOTATATE PET/CT independently predicts early failure on SSA monotherapy in patients with well-differentiated grade 1-2 GEP-NET. Patients with lack of expected benefit from SSA therapy can be readily identified using routine 68 Ga-DOTATATE PET/CT with very high specificity. The Oncologist 2020;25:1-9 Implications for Practice: Based on 68 Ga-DOTATATE positron emission tomography-computed tomography imaging, clinicians can better inform patients on the expected benefit of somatostatin analog therapy for gastroenteropancreatic neuroendocrine tumors, especially when access to the therapy is difficult, and offer proactive discussion on alternative management options.

[68Ga]Ga-DOTA-FAPI-04 and [18F]FDG PET/CT in the Assessment of Pancreatic Tumors: A Comparison Study

“…The [ 68 Ga]Ga-DOTA-FAPI-04 uptake is much lower when compared to PDAC, implying the low expression of FAP. [ 68 Ga]Ga-DOTA-TATE has an established role in diagnosing NENs [27,28]. In our study, one patient with NET (G2) also conducted [ 68 Ga]Ga-DOTA-TATE PET/CT and the corresponding liver metastases (FAPI − /FDG − ) showed intense uptake.…”

Successful Treatment with &lt;sup&gt;177&lt;/sup&gt;Lutetium-Dotatate and Maintenance Octreotide in a Patient with Esthesioneuroblastoma with Central Nervous System Invasion: Case Report and Review of the Literature

“…There is a clear relation between SUV uptake (minimum, maximum, and mean) with the selection of patients for PRRT, which can explain differences in response and should be used to select patients for PRRT. Previous studies showed that low SUVmax on 68Ga-DOTATATOC PET-CT independently predicts early failure on somatostatin receptor analog monotherapy in patients with well-differentiated grade 1 -2 NET [24].…”

Ga-68-Edotreotide Positron Emission Tomography/Computed Tomography Somatostatin Receptors Tumor Volume Predicts Outcome in Patients With Primary Gastroenteropancreatic Neuroendocrine Tumors

“…Pauwels et al 18 The same as for volumetric parameters, only few studies focused on SUVmax as a predictive parameter in GEP-NET. 13,23 Low SUVmax on [ 68 Ga]Ga-SSTR PET was associated with worse prognosis in well-differentiated GEP-NET predicting early failure on SSA monotherapy. In addition, [ 68 Ga]Ga-SSTR PET/CT, via SUVmax, impacted on the management of NET patients, leading to a change in treatment decision in about one-third of patients.…”