Self-Administration of Long-Acting Somatostatin Analogues in NET Patients-Does It Affect the Clinical Outcome?

Background and Objectives: Long-acting somatostatin analogues (SSA) (octreotide LAR and lanreotide Autogel) are recommended as first line treatment of locally advanced or metastatic well-differentiated neuroendocrine tumors (NETs) with a good expression of somatostatin receptor (SSTR). Both of these SSAs are usually administered via injections repeated every 4 weeks. The purpose of the study was to compare the route of SSA administration (injection performed by professional medical staff and self-administration of the drug) with progression-free survival. Materials and methods: 88 patients in 2019 and 96 patients in 2020 with locally advanced or metastatic well-differentiated NETs were included in the study. All patients had a good expression of SSTR type 2 and had been treated for at least 3 months with a stable dose of long-acting somatostatin analogue every 4 weeks. All of them had received training on drug self-injections from professional NET nurses at the beginning of the COVID-19 epidemic. Results: The rate of NET progression in the study group in 2020 was higher than in 2019 29.1% vs. 18.1% (28 vs. 16 cases), p = 0.081. Conclusions: The method of administration of long-acting SSA injection performed 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.

The Usefulness of [18F]F-Fluorodeoxyglucose and [18F]F-Sodium Fluoride Positron Emission Tomography Imaging in the Assessment of Early-Stage Aortic Valve Degeneration after Transcatheter Aortic Valve Implantation (TAVI)-Protocol Description and Preliminary Results.

Transcatheter aortic valve implantation (TAVI) is now a well-established treatment for severe aortic stenosis. As the number of procedures and indications increase, the age of patients decreases. However, their durability and factors accelerating the process of degeneration are not well-known. The aim of the study was to verify the possibility of using [18F]F-sodium fluoride ([18F]F-NaF) and [18F]F-fluorodeoxyglucose ([18F]F-FDG) positron emission tomography/computed tomography (PET/CT) in assessing the intensity of TAVI valve degenerative processes. In 73 TAVI patients, transthoracic echocardiography (TTE) at initial (before TAVI), baseline (after TAVI), and during follow-up, as well as transesophageal echocardiography (TEE) and PET/CT, were performed using [18F]F-NaF and [18F]F-FDG at the six-month follow-up (FU) visit as a part of a two-year FU period. The morphology of TAVI valve leaflets were assessed in TEE, transvalvular gradients and effective orifice area (EOA) in TTE. Calcium scores and PET tracer activity were counted. We assessed the relationship between [18F]F-NaF and [18F]F-FDG PET/CT uptake at the 6 = month FU with selected indices e.g.,: transvalvular gradient, valve type, EOA and insufficiency grade at following time points after the TAVI procedure. We present the preliminary PET/CT ([18F]F-NaF, [18F]F-FDG) results at the six-month follow-up period as are part of an ongoing study, which will last two years FU. We enrolled 73 TAVI patients with the mean age of 82.49 ± 7.11 years. A significant decrease in transvalvular gradient and increase of effective orifice area and left ventricle ejection fraction were observed. At six months, FU valve thrombosis was diagnosed in four patients, while 7.6% of patients refused planned controls due to the COVID-19 pandemic. We noticed significant correlations between valve types, EOA and transaortic valve gradients, as well as [18F]F-NaF and [18F]F-FDG uptake in PET/CT. PET/CT imaging with the use of [18F]F-FDG and [18F]F-NaF is intended to be feasible, and it practically allows the standardized uptake value (SUV) to differentiate the area containing the TAVI leaflets from the SUV directly adjacent to the ring calcifications and the calcified native leaflets. This could become the seed for future detection and evaluation capabilities regarding the progression of even early degenerative lesions to the TAVI valve, expressed as local leaflet inflammation and microcalcifications.