Impact of Octreotide Long-Acting Release on Tumour Growth Control as a First-Line Treatment in Neuroendocrine Tumours of Pancreatic Origin

Abstract

Background: Somatostatin analogues (SSA) are widely used in the treatment of patients with functioning and non-functioning neuroendocrine tumours (NET). The aim of our investigation was to evaluate the antiproliferative effect of SSA in patients with pancreatic NET. Methods: We retrospectively analysed records of 43 patients with pancreatic NET treated at our clinic with octreotide long-lasting release as a first-line therapy. The aim of our study was to investigate the overall best response according to the RECIST criteria, overall best response defined as disease control rate (SD+PR), response and disease control rate at 12 months, and time to tumour progression (TTP). Results: The mean age (± SD) of the patients (16 female/27 male) at initial diagnosis was 54.7 ± 11.86 years. At the start of therapy, 39 of 43 patients were classified as stage IV according to ENETS-TNM. Tumours were graded, based on MiB-1/Ki67 staining, as G1 (n = 8), G2 (n = 30) or unknown (n = 5). The octreoscan was positive in 37 patients, negative in 2 and unknown in 4 cases. Nineteen patients had functioning tumours, 24 patients had non-functioning tumours. Median overall survival was 98 months, and median TTP was 13 months. Analysis of grading showed a statistically significant influence on TTP when comparing the median TTP for Ki67 >10% with Ki67 <5% (p = 0.009) and Ki67 5-10% (p = 0.036). Conclusion: SSA may be considered as a first-line treatment for antiproliferative purposes in metastatic NET of the pancreas. Patients with a proliferation index <10% displayed a more durable response compared to those with a higher proliferation index.