An assessment of 18 F-FDG PET/CT for thoracic screening and risk stratification of pulmonary nodules in multiple endocrine neoplasia type 1

Optimization of Precursor Synthesis Conditions of (2S,4S)4–[18F]FPArg and Its Application in Glioma Imaging

Although the tracer (2S,4S)4–[¹⁸F]FPArg is expected to provide a powerful imaging method for the diagnosis and treatment of clinical tumors, it has not been realized due to the low yield of chemical synthesis and radiolabeling. A simple synthetic method for the radiolabeled precursor of (2S,4S)4–[¹⁸F]FPArg in stable yield was obtained by adjusting the sequence of the synthetic steps. Furthermore, the biodistribution experiments confirmed that (2S,4S)4–[¹⁸F]FPArg could be cleared out quickly in wild type mouse. Cell uptake experiments and U87MG tumor mouse microPET–CT imaging experiments showed that the tumor had high uptake of (2S,4S)4–[¹⁸F]FPArg and the clearance was slow, but (2S,4S)4–[¹⁸F]FPArg was rapidly cleared in normal brain tissue. MicroPET–CT imaging of nude mice bearing orthotopic HS683–Luc showed that (2S,4S)4–[¹⁸F]FPArg can penetrate blood–brain barrier and image gliomas with a high contrast. Therefore, (2S,4S)4–[¹⁸F]FPArg is expected to be further applied in the diagnosis and efficacy evaluation of clinical glioma.

The Management of Neuroendocrine Tumors of the Lung in MEN1: Results From the Dutch MEN1 Study Group

INTRODUCTION

Multiple endocrine neoplasia type 1 (MEN1)-related neuroendocrine tumors (NETs) of the lung are mostly indolent, with a good prognosis. Nevertheless, cases of aggressive lung NET do occur, and therefore the management of individual patients is challenging.

AIM

To assess tumor growth and the survival of patients with MEN1-related lung NETs at long-term follow-up.

METHODS

The population-based Dutch MEN1 Study Group database (n = 446) was used to identify lung NETs by histopathological and radiological examinations. Tumor diameter was assessed. Linear mixed models and the Kaplan-Meier method were used for analyzing tumor growth and survival. Molecular analyses were performed on a lung NET showing particularly aggressive behavior.

RESULTS

In 102 patients (22.9% of the total MEN1 cohort), 164 lesions suspected of lung NETs were identified and followed for a median of 6.6 years. Tumor diameter increased 6.0% per year. The overall 15-year survival rate was 78.0% (95% confidence interval: 64.6-94.2%) without lung NET-related death. No prognostic factors for tumor growth or survival could be identified. A somatic c.3127A > G (p.Met1043Val) PIK3CA driver mutation was found in a case of rapid growing lung NET after 6 years of indolent disease, presumably explaining the sudden change in course.

CONCLUSION

MEN1-related lung NETs are slow growing and have a good prognosis. No accurate risk factors for tumor growth could be identified. Lung NET screening should therefore be based on well-informed, shared decision-making, balancing between the low absolute risk of an aggressive tumor in individuals and the potential harms of frequent thoracic imaging.