Endocrine Abstracts

Introduction: High doses/frequency of somatostatin analogues (SSA) are often used to control refractory functional symptoms and/or tumour progression in patients treated with standard doses of SSAs, but there is limited evidence for the efficacy of this strategy.

Methods: Retrospective analysis of 47 NET patients on lanreotide Autogel 120 mg every 3 weeks (as monotherapy). Progression-free survival (PFS) and clinical outcomes were assessed. A 30% change in symptomatology and biomarker levels was considered significant.

Results: Mean age was 62±12 years. The primary tumour site was in the small bowel in 72%, colon/rectum in 13%, pancreas in 11%, lung in 2% and unknown in 2% of cases. Tumour grade was G1 in 49%, G2 (Ki67 2–5%) in 26%, G2 (Ki67 6–20%) in 13%, G3 in 2% (grade unavailable in 10%). Locoregional spread was present in 92% and liver metastases in 85% of patients. Treatment indications were control of functional symptoms (51%), disease progression (38%) and /or increasing biomarkers (11%). Median PFS was 25 months (95% CI 5, 45). In patients with refractory functional symptoms, diarrhoea and flushing improved significantly in 17% and remained stable in 39% of cases. In patients with available biomarkers before and after treatment, CgA and U-5-HIAA levels significantly reduced in 58 and 15% while they remained stable in 16 and 20% of cases, respectively. Treatment was discontinued in 34 cases because of death (8), radiological progression (10), ongoing symptoms (8), a combination of disease progression/functional symptoms (6) and side effects (2). Treatment after discontinuation included PRRT (15), interferon (2), everolimus (2), sunitinib (1), chemotherapy (1), reduction of the administration interval to 2-weekly (1), increase of the lanreotide dose to 180 mg (1), octreotide LAR (1), while one patient was palliated and another returned to standard doses of lanreotide due to side effects on the high frequency regimen.

Conclusions: The use of a shortened interval of lanreotide Autogel administration in patients with radiological and/or symptomatic progression on standard doses of SSA therapy is effective and may prevent or delay the use of other treatments with a more toxic side effect profile.