Evaluation of PET-CT Using Somatostatin Agonists Labeled With Gallium68 in Neuroendocrine Tumors

Evaluation of PET-CT Using Somatostatin Agonists Labeled With Gallium68 in Neuroendocrine Tumors

Gastro-Entero-Pancreatic tumors (GEPs) are a subset of Neuroendocrine tumors (NETs) derived from the primitive gut and include digestive and bronchial NETs.

Historically, the gold standard in their functional exploration is the "conventional" somatostatin receptors scintigraphy (SRS) labeled with Indium-111 (Octreoscan®). This reference imaging is complementary to Tomography (CT) and liver MRI. However SRS sensitivity is moderate (60 %), because of its intrinsic detection limits, which could delay the diagnosis or lead to inappropriate therapy.

The use of somatostatin agonists (DOTATOC, DOTATATE, DOTANOC), radiolabeled with gallium-68 (68Ga) enables targeting of Somatostatin receptors (SSTRs) with a PET resolution. This has improved diagnosis of TNE with a gain in sensitivity of over 20% compared to SRS. Furthermore, patient irradiation and imaging protocol are significantly reduced.

Inclusion Criteria:

• • Age ≥ 18,

  • Patient with one of the following situations : suspicion of GEP, initial staging of non-metastatic GEP, GEP with unknown primary tumor, Restaging of GEP justifying focused therapeutic approach
  • Reference imaging within the last 3 months: multiphasic thoracoabdominal CT scan, liver MRI and SRS (SPECT/CT).

Exclusion Criteria:

• Pregnant or breast-feeding woman
• Other cancer disease
• GEP with grade 3 tumours
• Non GEP TNE (paragangliome, medullar thyroid cancer)