Endocrine Abstracts

Introduction: Escalated doses of octreotide LAR are commonly used to control functional symptoms and/or tumour growth, but there is limited evidence regarding the efficacy of this approach.

Methods: Retrospective analysis of 69 NET patients treated with octreotide LAR 30 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 64±11 years. The primary tumour site was in the small bowel in 74% of cases, colon/rectum in 9%, lung 6%, pancreas 4% and unknown in 7%. 41% of tumours were G1, 28% G2 (Ki67 2–5%), 10% G2 (Ki67 6–20%) (grade unavailable in 22%). Loco-regional spread was present in 36% and liver metastases in 55% of cases. Treatment indications were control of functional symptoms (62%), disease progression (33%) and/or increasing biomarkers (10%). Median PFS was 25 months (95% CI 6, 44). Median PFS in patients with radiologically progressive disease was significantly shorter than those with stable disease at initiation of treatment (11 vs 38 months). Diarrhoea and flushing improved significantly in 36 and 14% of patients who received treatment for ongoing functional symptoms, while they remained stable in 46 and 59% of cases, respectively. In patients with available biomarkers before and after treatment, CgA and U-5-HIAA levels reduced significantly in 35 and 29% while they remained stable in 20 and 29% of cases, respectively. Treatment was discontinued in 45 cases because of death (7), disease progression (15), ongoing functional symptoms (9), a combination of radiological progression and ongoing symptomatology (10), symptomatic deterioration and increasing biomarkers (2) and side effects (2). Treatment after discontinuation of the 3-weekly regimen included PRRT (22), interferon (4), sunitinib (1), chemotherapy (1), lanreotide autogel (3), further reduction of the interval of administration to 2-weekly (2), everolimus (2), MIBG therapy (1), external beam radiotherapy (1) and transarterial embolization (1).

Conclusions: A shortened interval of octreotide LAR administration is well-tolerated and can be effectively used as maintenance therapy or as a bridge to other therapies in patients with progressive disease and/or symptomatology.