Long-acting somatostatin analogues are highly effective in men1 patients with early stage duodeno-pancreatic neuroendocrine tumors

A. Faggiano; V. Ramundo; Prete M. Del; V. Marotta; F. Marciello; L. Camera; V. Napolitano; L. De; G. Lombardi; A. Colao

Somatostatin analogues (SSA) represent a recognized therapeutic option in patients affected with functioning neuroendocrine tumors (NET). In non-functioning NET, SSA are reported to induce tumor stabilization in most of cases and objective response in <5%. NET associated to Multiple Endocrine Neoplasia type 1 (MEN1) are inherited tumors, generally located in the duodeno-pancreatic trait, characterized by well differentiated histotype, high expression of somatostatin receptors and diagnosed at an early stage because of the genetic screening in all first-degree relatives of MEN1 patients. All these features make MEN1 NET susceptible to respond to SSA, however, this has never been specifically investigated.

To evaluate the efficacy of long-acting SSA in MEN1 patients affected with duodeno-pancreatic NET.

All first-degree relatives of MEN1 subjects who genetically diagnosed for MEN1 before the clinical diagnosis of NET and with evidence of one or more duodeno-pancreatic NET <15 mm in size were enrolled. Twenty-four patients with MEN1-related duodeno-pancreatic NET (age range 21–42 yrs) were treated with octreotide LAR or lanreotide autogel at standard doses. Treatment duration ranged 6–76 months. At the radiological evaluation (performed by multidetector-row computed tomography and endoscopic ultrasound), multiple duodeno-pancreatic NET (range 1–9), sized 3–14 mm, were detected.

An objective tumor response was observed in 17%, stable disease in 75% and progression of disease in 8% of cases. Due to the low number of progressions, the median time-to-progression could not be estimated. In seven patients with abnormally increased gastrin, insulin and/or chromogranin-A serum concentrations, a complete hormonal response was observed in 100% cases and was stable along the follow-up.

In conclusions, therapy with SSA is highly effective in patients with early stage MEN1 duodeno-pancreatic NET, resulting in long-time suppression of tumor and hormonal activity. Objective response is 17%, suggesting that MEN1 NET is a subgroup more sensitive to SSA than sporadic NET.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.

Endocrine Abstracts

P807