This is a prospective, multicenter, open-label study designed to evaluate the specificity and sensitivity of the Inflammation Based Index (IBI) score as a marker for predicting clinical and radiological response in patients treated with Lu-177 oxodotreotide for inoperable or metastatic, progressive, grade 1 or 2 intestinal neuroendocrine tumors.

This IBI score will be assessed on the basis of C-reactive protein (CRP) and albumin values, and will be defined as follows:

• IBI = 0: Low mortality risk (if CRP and serum albumin values are considered normal in the investigator's judgment).
• IBI > 0, including: IBI = 1: Intermediate risk of mortality (if one of the two values is considered abnormal and clinically significant according to the investigator's judgment (either hypoalbuminemia or elevated CRP)); IBI = 2: High mortality risk (if both values are considered abnormal and clinically significant according to the investigator's judgment (hypoalbuminemia and elevated CRP)).

Patients were followed up for 36 months.

A total of 150 patients should be included in this study.

Inclusion Criteria:

1. Patient aged ≥ 18 years.
2. Patient with histologically confirmed grade 1 or 2 neuroendocrine tumor of the midgut, inoperable or metastatic.
3. Patient eligible for Lu-177 oxodotreotide therapy in accordance with its marketing authorization.
4. Evidence of progression in the 12 months preceding Lu-177oxodotreotide therapy, confirmed by imaging techniques commonly used in current practice (thoraco-abdomino-pelvic CT and/or liver MRI, Ga-68 DOTA somatostatin analog PET-CT) +/- liver involvement greater than 50%.
5. Disease measurable according to RECIST 1.1 criteria in thoraco-abdomino-pelvic CT +/- liver MRI.
6. Patient affiliated to a social security scheme in France.
7. Patient having signed informed consent prior to study inclusion and prior to any specific study procedure.

Exclusion Criteria:

1. Previous treatment with Lu-177 oxodotreotide.
2. Any contraindication to treatment with Lu-177 oxodotreotide.
3. Morbid obesity (BMI > 40).
4. Uncontrolled/unbalanced active inflammatory disease in the 3 months prior to inclusion.
5. Active carcinoid heart disease or other acute cardiovascular event.
6. Active infection not treated within 15 days.
7. Pregnant or breast-feeding woman.
8. Any psychological, family, geographical or sociological condition that prevents compliance with the medical follow-up and/or procedures stipulated in the study protocol.
9. Patient deprived of liberty or under legal protection (guardianship, legal protection).