The LARO-MEN1 study: a longitudinal clinical experience with octreotide Long-Acting Release in patients with Multiple Endocrine Neoplasia type 1 Syndrome.

Multiple endocrine neoplasia type 1 (MEN1) is a rare hereditary tumoral syndrome, featured by a combination of neoplasms of various endocrine and nonendocrine tissues. Approximately 33% of MEN1-related deaths are due to the malignant behaviour of well-differentiated neuroendocrine tumors (NETs), for which a preventive surgical treatment is not feasible. Somatostatin analogues (SSA) have been employed in the treatment of NETs in the stage of advanced or metastatic disease, in order to control the growth and secretion of tumor lesions. A longitudinal, open label study named "LARO-MEN1" was undertaken in order to assess whether early medical treatment with long-acting SSA could act as a preventive approach in small MEN1-related gastroenteropancreatic (GEP) NETs. Thirty consecutive patients affected by MEN1 were screened and 8 patients with small (<2 cm) NETs and abnormal laboratory values of at least one of the GEP hormones were administered octreotide acetate slow-release formulation (LAR) (10 mg i.m. every 28 days). Octreotide LAR was effective in decreasing GEP hormones and overall safe in the majority of patients up to six years of treatment, maintaining the disease stable also in terms of tumor size. The positive outcomes of this study in MEN1 patients reinforce the results obtained in advanced NETs on the use of SSA, opening to the opportunity for preventive use of octreotide LAR, aimed to delay or even avoid surgery in these patients.