Comparison of 18F Labeled Analog of MIBG (18F-MFBG) PET/CT and 123I-MIBG SPECT in Pediatric Patients With Neuroblastoma.

Neuroblastoma is one of the most common malignancies of childhood: 130 to 150 new cases are recorded each year in France. Currently, 123I-metaiodobenzylguanidine scintigraphy (123I-MIBG scan) is considered as a gold standard in neuroblastoma for assessing metastatic extension, as well as planning and evaluating response to treatment or detecting relapse. Regretfully, 123I-MIBG scintigraphy implies many disadvantages for our patients, mainly the length of the procedure (planned on two consecutive days), length of the imaging (45-90 minutes) and the required premedication for thyroid protection.

18F-metafluorobenzylguanidine (18F-MFBG) is a new specific Positron Emission Tomography (PET) tracer providing a specific Norepinephrine transporter (NET) expressing imaging with fluor-18, a routinely available radionuclide that offers higher resolution for lesion detection and shorter acquisitions for pediatric patients, and potentially lower radiation exposure.

The NEUROBLASTOTEP trial aims at demonstrating that 18F-MFBG PET/CT diagnostic performances are at least as good as 123I-MIBG scintigraphy (current gold standard imaging radiotracer in neuroblastoma).

• 18F-MFBG PET/CT imaging (Procedure): Participants will receive the 18F-MFBG tracer and undergo a PET/CT imaging.

Primary outcomes

• Diagnostic agreement between 18F-MFBG PET/CT (new procedure) and 123I-MIBG scintigraphy (gold standard) [The day of the PET/CT procedure]: % patients in whom concordance between the 2 procedures is reached.

Secondary outcomes

• Description of discrepancies [The day of the PET/CT procedure]: In case of non-perfect agreement, the observed discrepancies will be described. Agreement between the SIOPEN and Curie scores will be estimated.
• Dosimetric comparison between the two procedures [The day of the PET/CT procedure]: One-point activity concentration measurement for normal organs (lung, liver, renal parenchyma, pancreas, spleen, adrenal gland, bladder, thyroid, heart, gonadic, eyes).
• Improvement of patient management during the diagnostic procedure [The day of the PET/CT procedure]: Improvement of patient management will be evaluated by a short satisfaction survey after PET procedure, using satisfaction scales. The satisfaction and feeling variables will be described for the 123I-MIBG scintigraphy and 18F-MFBG PET/CT examinations by their repartition for the qualitative variables and by their distribution
• Optimization the 18F-MFBG PET procedure (dose injected, imaging protocol) [The day of the PET/CT procedure]: PET images will be acquired in list-mode to ensure multiple reconstruction for different acquisition duration, in order to determine optimal duration.
• Optimization the 18F-MFBG PET procedure (dose injected, imaging protocol) [The day of the PET/CT procedure]: PET images will be acquired in list-mode to ensure multiple reconstruction for different acquisition duration, in order to determine optimal injected activity

Sex: All, ages: 365 Days to 17 Years

Inclusion Criteria:

1. Patients with histologically proven neuroblastoma.
2. Relapsed or refractory neuroblastoma.
3. 123I-MIBG avid neuroblastoma (positive 123I-MIBG scintigraphy = showing at least one neuroblastoma lesion (either primary or metastatic) with a significant avidity for 123I-MIBG), performed within 2 weeks to 2 days prior to 18F-MFBG PET/CT.
4. No specific treatment for neuroblastoma between 123I-MIBG scintigraphy and 18F-MFBG PET/CT (PET/CT shall not delay therapeutic management.)
5. Age ≥ 365 days to < 18 years old. For children under 13 months, day of birth should be collected.
6. Weight ≥ 9 kg.
7. Performance Status: Lansky or Karnofsky ≥ 60%.
8. Signed written informed consent by the 2 holders of the parental authority or legal representative(s).
9. Patients covered by a health insurance system.

Exclusion Criteria:

1. Patient inability to comply with protocol requirements without general anesthesia.
2. Pregnant or breastfeeding patient. If indicated, at the investigator's discretion, patients of childbearing potential should have urinary pregnancy test the day of the PET/CT procedure, prior to the MFBG administration.
3. Any treatment likely to interact with MIBG initiated/modified between scintigraphy with MIBG and PET/CT with MFBG.
4. Patient with a parent or legal representative with altered mental status or psychiatric disorder that, in the opinion of the investigator, would preclude a valid informed consent

• Tissot Hubert, MD, Principal investigator, Institut Curie