Efficacy and safety of high doses of long-acting somatostatin analogues for treatment of well differentiated functioning neuroendocrine tumors
P Ferolla1, A Faggiano2, R Pivonello2, G Lombardi2, G Angeletti1, A Colao2 & F Santeusanio1
Introduction: Somatostatin analogues (SSA) represent the main therapeutic option in patients affected with functioning well-differentiated neuroendocrine tumors (NET). However, after a variable time from the start of the therapy tachyphylaxys may cause lack of control of clinical syndrome and progression of the disease.
Aim: The aim of this preliminary study was to evaluate efficacy in terms of reduction of circulating markers, control of the clinical syndrome and stabilization of disease with the use of high doses of SSA in a group of functioning NET with progressive disease during standard therapy with SSA. Safety was also assessed.
Patients and methods: Long-acting SSA (Octreotide LAR 30 mg) was administered every 21 days in 16 well-differentiated functioning NET with progressive disease (lack of control of associated clinical syndrome and progression of the disease in course of therapy with standard doses (20 or 30 mg every 28 days). Control of symptoms and secretory pattern were evaluated basally and after three month of therapy.
Results: High doses therapy results in controls of associated clinical syndrome in 100% of cases. A reduction of at least 30% of secretory pattern was achieved in 85% of cases. Stabilization of disease was obtained at 3 month in 95% of cases. No further adverse effects were registered comparing high doses with standard therapeutic regimen apart from 2 cases with asymptomatic cholelithiasis.
Conclusion: High doses SSA therapy showed high efficacy in controlling clinical associated syndromes and reduce secretory neuroendocrine pattern when compared to standard therapy in patients with progressive disease in course of therapy with standard doses. No significative addictive adverse effect were linked to the increase of dosage. We conclude that high doses therapy should always be considered in the management of NET patients with progressive disease.