Endocrine Abstracts

Background

Somatostatin analogues (SSA) (octreotide and lanreotide) are recommended as a first line treatment of locally advanced or metastatic well-differentiated neuroendocrine tumors (NETs) with a good expression of somatostatin receptor (SSTR). Both of them are usually used in injection repeated every 4 weeks.

The study objective

Was to compare the way of SSA administration (injection performed by professional medical staff before epidemic period and self-administration of the drug forced by the COVID-19 epidemic restrictions) to progression free survival (PFS) in patients with locally advanced or metastatic NETs.

Materials and methods

88 patients in 2019 and 96 patients in 2020 with locally advanced or metastatic well-differentiated NETs (G1 and G2) treated in the Clinical Department of Endocrinology in Krakow, Poland, were included to the study. All patients had a good expression of SSTR type 2 assessed in functional somatostatin receptor imaging and were treated for at least 3 months with a stable dose of lanreotide Autogel 120 mg or 30 mg of octreotide LAR every 4 weeks. Prior to change of way of drug administration at the beginning of the COVID-19 epidemic period all of them were trained in regards to drug self-injections by the professional NET nurses. A retrospective analysis was performed, based on the medical documentation. Time to progression (TTP) was defined as the time beginning from the use of the first SSA dose to the time of progression confirmed by radiological examinations: computed tomography (CT) or magnetic resonance imaging (MRI).

Results

The rate of NET progression in the study group in 2020 was higher than in 2019 28, 1% vs 18, 2% (27 vs 18 cases), p=0, 079. The analyzed groups did not differentiate in regards to age, follow-up period, performance status and tumor burden (assessed as liver, lymph nodes and bone involvement). The mean TTP was in 2019 56.8 months (range: 8-144) and in 2020 56.0 months (range: 6-152). In 2019 no progressions were diagnosed in patients with G1 tumors, whereas in 2020 the progression was observed in 7 patients with G1. The greatest increase in the incidence of progression was seen among patients with small bowel NETs.

Conclusions

The way of long-acting SSA administration: injection done by professional medical staff vs self-injection of the drug may significantly affect the risk of NET progression. The unequivocal confirmation of such a relationship requires further observation.