Outcome on Mesenteric Mass Response of Small-Intestinal Neuroendocrine Tumors Treated by 177Lu-DOTATATE Peptide Receptor Radionuclide Therapy: The MesenLuth Study, a National Study from the French Group of Endocrine Tumors and Endocan-RENATEN Network.

A mesenteric mass (MM), characterized by fibrotic reaction, is present in most small-intestinal neuroendocrine tumors (SI-NETs). 177Lu-DOTATATE peptide receptor radionuclide therapy (PRRT) has shown its efficacy in patients with progressive SI-NETs. However, because of specific tissue characteristics of desmoplastic MMs, we hypothesize that these lesions may be refractory to 177Lu-DOTATATE PRRT. Methods: From the national French Groupe d'étude des Tumeurs Endocrines database, we identified patients with an advanced SI-NET and a MM (≥2 cm with a retractile aspect) of a SI-NET treated by at least 1 course of 177Lu-DOTATATE PRRT. The primary endpoint was a MM objective response rate (ORR) of less than 5%. Secondary endpoints were metabolic response, MM-related safety, and clinical response, as well as MM progression-free survival (PFS) and non-MM PFS. Results: In total, 52 patients were included. The MM ORR was 4% (n = 2), and the non-MM ORR was 8% (n = 4). No patient had a MM metabolic response, and the non-MM metabolic response rate was 12% (n = 6). Among the 26 patients with baseline MM-related symptoms, 46% had a clinical response. Four patients presented with gastrointestinal complications during PRRT. The median MM-related PFS was not reached, and the non-MM PFS was 50.3 mo (95% CI, 38.2-61.7 mo). Conclusion: This study confirms that 177Lu-DOTATATE PRRT does not lead to morphologic response on MMs (ORR < 5%). However, it allows MM stability, with few MM-related side effects, and has a relevant impact on MM-related symptoms.

Proof of Concept of the Radiosensitizing Effect of Gadolinium Oxide Nanoparticles in Cell Spheroids and a Tumor-Implanted Murine Model of Chondrosarcoma.

Purpose: Chondrosarcomas (CHSs), which represent 20% of primary bone tumors in adults, are mostly resistant to radio- and chemotherapy. It is therefore essential that new therapeutic approaches, targeted to the tumour, be developed to improve the prognosis of patients. The effectiveness, as a radiosensitizing agent, of gadolinium oxide nanoparticles (GdoNP, AGuIX®) nanoparticles in CHS was evaluated in vitro, in spheroid CHS models allowing to reproduce cell-cell extracellular matrix interactions, and, in vivo, in a nude mouse model with heterotopic tumour xenograft. Methods: Spheroids from SW1353 and HEMC-SS cells were characterized by confocal microscopy with or without GdoNP treatment. Real-time microscopy enabled quantification of cell viability, cell migration and invasion. In vivo, the efficacy of the association of GdoNP combined with a single (4Gy) or fractionated (4x1Gy) irradiation was evaluated in HEMC-SS tumor-bearing mice by monitoring tumor growth, mouse survival and gene expression profile. Results: The expression of proteoglycans in the extra-cellular matrix (ECM) of spheroids demonstrated the relevance of the 3-D model. The combination of GdoNP with single or fractionated irradiation increased the lethal effects of irradiation on 2-D- and 3-D-cultured cells. In vivo, a single or a fractionated dose of 4 Gy associated with IT or IV injection of GdoNP decreased tumor growth significantly. Only IT injection increased mice survival. Unexpectedly, the radiosensitizing effect of GdoNP was associated, in vitro, with a significant decrease in invasion-migration capacities and, in vivo, with the decreased expression of PTX3, a protein involved in the epithelial-to-mesenchymal transition process, suggesting a potential impact of GdoNP on metastasis formation. Conclusion: These results provide the first proof of concept of the radiosensitizing effect of GdoNP in CHSs and opened the way for a multicentre, randomized Phase 2 trial evaluating the association of GdoNP with radiotherapy for the therapeutic management of patients with symptomatic inoperable musculoskeletal tumor lesions.

Amino Acid Solutions for 177Lu-Oxodotreotide Premedication: A Tolerance Study.

Background: The co-infusion of amino acid solutions during peptide receptor radionuclide therapy reduces the tubular reabsorption of 177Lu-oxodotreotide, thus minimizing nephrotoxicity. In our nuclear medicine department, the patients received two different types of amino acid perfusion over time: a commercial solution (CS) containing 10% amino acids, and a 2.5% lysine−arginine (LysArg) hospital preparation, produced by a referral laboratory. The aim of the present study was to analyze the tolerance of the two amino acid solutions. Methods: The patient files were analyzed and double-checked. The study parameters comprised the gender, age, primary tumor site, type of amino acid perfusion, adverse events (AE) and WHO AE grades, antiemetic premedication, creatinine, and serum potassium level. Results: From February 2016 to February 2019, 76 patients were treated, for a total 235 cycles. AEs occurred in 71% of the CS cycles (n = 82/116), versus 18% (n = 21/119) in the LysArg group (p < 0.0001). In the CS group, the AEs were mostly WHO grade 4 (n = 24/82), and mostly grade 1 in the LysArg group (n = 13/21). Poisson regression showed a higher risk of AE overall and of grades 3 and 4 in the females and with CS. The mean creatinine clearance was identical before and after the PRRT cycles, whichever amino acid perfusion was used. Conclusions: The lysine−arginine preparation showed better tolerance than the commercial solution. The change to LysArg reduced the antiemetic premedication from four molecules to one.

Management of neuroendocrine neoplasms: conformity with guidelines in and outside a center of excellence.

Purpose: To improve neuroendocrine neoplasm (NEN) management, the European Neuroendocrine Tumor Society (ENETS) recognised 62 Centers of Excellence (CoE). This retrospective study compares conformity of patients' initial management within vs outside an ENETS CoE with clinical practice guidelines (CPGs). Methods: Patients diagnosed with a NEN between August 2018 and July 2020 and presented in the Lyon-CoE Multidisciplinary Tumour Board (MDT) were included. Factors potentially associated with the conformity of initial management (work-up and first treatment) to CPG underwent univariate and multivariate analyses. Results: Among the 615 included patients, 170 (27.6%) were initially managed in the CoE and 445 (72.4%) were only presented at the CoE-MDT. Patients in the CoE group more often had intestinal or pancreatic primaries, metastatic disease (61.8% vs 33%), hereditary syndrome, and a functioning tumour. Work-up conformity was 37.1% in the CoE (vs 29.9%, P = 0.09); this was 95.8% for the first treatment (vs 88.7%, P = 0.01). After multivariate analysis, CPG conformity was significantly higher for patients managed in the CoE, for younger patients, for those having a grade 1-2 tumour, and a genetic syndrome. Pancreatic and small intestinal (SI) NET surgeries performed in the CoE had a higher splenic preservation rate during left pancreatectomy, better detection of multiple tumours in SI surgeries, and higher number of resected lymph nodes. Conclusions: Given the widespread observance of CPG, not all patients require management in the CoE. Referral should be considered for more complex cases such as metastatic diseases, G2 tumours, or carcinoid syndromes. Finally, we should encourage the centralization of NET surgery.

Peptide Receptor Radionuclide Therapy by 177Lu-DOTATATE of a Secreting Cervical Paraganglioma.

ABSTRACT: A 59-year-old man with a parapharyngeal paraganglioma incidentally discovered on a cervical swelling was referred to our nuclear medicine department for a morpho-metabolic assessment. An 18F-FDG PET/CT was initially performed and found an intense hypermetabolism of the lesion and a hypermetabolism of the periadrenal brown fat evoking catecholamine secretion. An additional 68Ga-DOTATOC PET/CT was performed, showing an overexpression of the somatostatin receptors of this isolated paraganglioma. After multidisciplinary discussion, a peptide receptor radionuclide therapy with somatostatin analogs using 177Lu-DOTATATE as a compassionate measure was carried out.

Unexpected Vertebral Bodies Trapping of 99mTc-Macroaggregated Albumin During Lung Perfusion Scintigraphy in a Patient With Collateral Paravertebral Venous System.

ABSTRACT: A 35-year-old woman was referred to our nuclear medicine center for a ventilation and perfusion (VQ) pulmonary scintigraphy to detect pulmonary embolism. She was treated with low-molecular-weight heparin following a proximal venous thrombosis of the right upper limb and had a previous history of an infiltrating ductal carcinoma of the right breast. Surprisingly, the VQ scintigraphy showed uptake of 99mTc-MAA in several superior vertebrae. A contrast-enhanced CT scan revealed a dilated collateral paravertebral venous system due to the deep vein thrombosis extended from superior vena cava to brachiocephalic trunk. 99mTc-MAA was trapped through the dilated vertebral venous system.

Micron-sized and submicron-sized aerosol deposition in a new ex vivo preclinical model.

BACKGROUND: The knowledge of where particles deposit in the respiratory tract is crucial for understanding the health effects associated with inhaled drug particles. METHOD: An ex vivo study was conducted to assess regional deposition patterns (thoracic vs. extrathoracic) of radioactive polydisperse aerosols with different size ranges [0.15 µm-0.5 µm], [0.25 µm-1 µm] and [1 µm-9 µm]. SPECT/CT analyses were performed complementary in order to assess more precisely the regional deposition of aerosols within the pulmonary tract. Experiments were set using an original respiratory tract model composed of a human plastinated head connected to an ex vivo porcine pulmonary tract. The model was ventilated by passive expansion, simulating pleural depressions. Aerosol was administered during nasal breathing. RESULTS: Planar scintigraphies allowed to calculate the deposited aerosol fractions for particles in the three size ranges from sub-micron to micron The deposited fractions obtained, for thoracic vs. extra-thoracic regions respectively, were 89 ± 4 % vs. 11 ± 4 % for [0.15 µm-0.5 µm], 78 ± 5 % vs. 22 ± 5 % for [0.25 µm-1 µm] and 35 ± 11 % vs.65 ± 11 % for [1 µm-9 µm]. CONCLUSION: Results obtained with this new ex vivo respiratory tract model are in good agreement with the in vivo data obtained in studies with baboons and humans.