[Theranostics for Well and Moderately Differentiated GEP-NEN]

Area of Science:

• Nuclear Medicine
• Oncology
• Radiopharmacology

Background:

• Neuroendocrine neoplasms (NENs) are rare, heterogeneous tumors, with gastro-entero-pancreatic NENs (GEP-NENs) being the most common.
• Well-differentiated NENs often express somatostatin receptors (SSTRs), making them targets for nuclear medicine theranostics.
• Current classification of NENs relies on proliferative activity, indicated by the Ki-67 index (G1-3).

Purpose of the Study:

• To evaluate the efficacy of peptide receptor radionuclide therapy (PRRT) for SSTR-positive GEP-NENs.
• To highlight the role of SSTR-directed diagnostics, such as PET/CT, in patient selection and treatment planning.
• To inform treatment decisions for non-resectable, metastatic, or progressive well-differentiated GEP-NENs.

Main Methods:

• Diagnostic molecular imaging using somatostatin receptor-directed positron emission tomography/computed tomography (SSTR-PET/CT) for high sensitivity (93%) and specificity (96%).
• Peptide receptor radionuclide therapy (PRRT) administered intravenously over four cycles at 8-week intervals.
• Prospective evaluation of PRRT efficacy, exemplified by the NETTER-1 study.

Main Results:

• SSTR-PET/CT demonstrated high accuracy in diagnosing NENs and can guide radioguided surgery.
• The NETTER-1 study showed a significant improvement in progression-free survival, establishing PRRT as a key treatment.
• Lutathera (177Lu-DOTATATE) is approved for treating advanced, SSTR-positive GEP-NENs (G1 and G2).

Conclusions:

• PRRT, particularly with 177Lu-DOTATATE, is an effective, targeted therapy for well-differentiated GEP-NENs.
• SSTR-directed theranostics offer a personalized approach to managing NENs, improving patient outcomes.
• Treatment decisions for PRRT require interdisciplinary evaluation and documentation of tumor progression.