3134 - Treatment with somatostatin analogues after radiopeptide therapy

Background

Although neuroendocrine tumours (NET) constitute a very heterogeneous group, most of them express somatostatin receptors that enable treatment with somatostatin analogues, which proved to be effective both as bio- or radiopeptide therapy. However, little is now about combining these two treatment modalities. The aim of our prospective study was to evaluate the results of radiolabeled somatostatin analogues (PRRT) with or without "cold" somatostatin analogues (SA) as consolidation treatment.

Methods

Patients with well-differentiated NET treated with PRRT (4 to 5 cycles repeated every 6 to 12 weeks) were included in the study. After the last cycle of PRRT response to radiopeptide treatment was evaluated with the scintigraphic, radiological and biochemical examination. Thereafter patients were randomly assigned either to treatment with SA or observation group (2:1 randomization). Initiation of the next line of therapy was left to the discretion of treating physician. Patients were followed-up at 4-12 months intervals with radiological examinations (CT or MRI) and receptors scintigraphy. The median time to progression was measured from the start of PRRT treatment till the day of disease progression confirmed in the radiological or scintigraphic examination.

Results

125 patients (79 in SA and 46 in the observation group) were included in the study. 81 patients were randomly assigned to somatostatin analogs and 44 to the observation group. The median follow-up the calculated from the start of PRRT was 54 months for the whole group of patients. During that time 85 (68%) progressed. There was a trend to longer progression-free survival in SSA group (47 vs 44 months), however, the difference was statistically insignificant. During observation period 32 patients died and there was no difference in time to death between both groups. In 9 patients after radiopeptide therapy chemotherapy was given. Chemotherapy was well tolerated and there were no late serious side effects.

Conclusions

Preliminary results suggest that consolidation treatment with SA did not improve the results of PRRT. However, a larger number of patients and longer follow-up is necessary.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

D. Handkiewicz Junak: Travel / Accommodation / Expenses: Ipsen Novartis Genzyme-Sanofi. B. Jurecka-Lubieniecka: Travel / Accommodation / Expenses: Ipsen Novartis. B. Jarzab: Travel / Accommodation / Expenses: Ipsen Novartis Genzyme-Sanofi. All other authors have declared no conflicts of interest.