Frontiers in Oncology (Jan 2023)

Comparison of somatostatin receptor expression in patients with neuroendocrine tumours with and without somatostatin analogue treatment imaged with [18F]SiTATE

  • Ralf S. Eschbach,
  • Markus Hofmann,
  • Lukas Späth,
  • Gabriel T. Sheikh,
  • Astrid Delker,
  • Simon Lindner,
  • Klaus Jurkschat,
  • Carmen Wängler,
  • Björn Wängler,
  • Ralf Schirrmacher,
  • Reinhold Tiling,
  • Matthias Brendel,
  • Vera Wenter,
  • Franziska J. Dekorsy,
  • Mathias J. Zacherl,
  • Andrei Todica,
  • Andrei Todica,
  • Harun Ilhan,
  • Harun Ilhan,
  • Freba Grawe,
  • Freba Grawe,
  • Clemens C. Cyran,
  • Marcus Unterrainer,
  • Johannes Rübenthaler,
  • Thomas Knösel,
  • Thomas Knösel,
  • Tanja Paul,
  • Tanja Paul,
  • Stefan Boeck,
  • Stefan Boeck,
  • Christoph Benedikt Westphalen,
  • Christoph Benedikt Westphalen,
  • Christine Spitzweg,
  • Christine Spitzweg,
  • Christoph J. Auernhammer,
  • Christoph J. Auernhammer,
  • Peter Bartenstein,
  • Peter Bartenstein,
  • Lena M. Unterrainer,
  • Leonie Beyer,
  • Leonie Beyer

DOI
https://doi.org/10.3389/fonc.2023.992316
Journal volume & issue
Vol. 13

Abstract

Read online

PurposeSomatostatin analogues (SSA) are frequently used in the treatment of neuroendocrine tumours. Recently, [18F]SiTATE entered the field of somatostatin receptor (SSR) positron emission tomography (PET)/computed tomography (CT) imaging. The purpose of this study was to compare the SSR-expression of differentiated gastroentero-pancreatic neuroendocrine tumours (GEP-NET) measured by [18F]SiTATE-PET/CT in patients with and without previous treatment with long-acting SSAs to evaluate if SSA treatment needs to be paused prior to [18F]SiTATE-PET/CT.Methods77 patients were examined with standardised [18F]SiTATE-PET/CT within clinical routine: 40 patients with long-acting SSAs up to 28 days prior to PET/CT examination and 37 patients without pre-treatment with SSAs. Maximum and mean standardized uptake values (SUVmax and SUVmean) of tumours and metastases (liver, lymphnode, mesenteric/peritoneal and bones) as well as representative background tissues (liver, spleen, adrenal gland, blood pool, small intestine, lung, bone) were measured, SUV ratios (SUVR) were calculated between tumours/metastases and liver, likewise between tumours/metastases and corresponding specific background, and compared between the two groups.ResultsSUVmean of liver (5.4 ± 1.5 vs. 6.8 ± 1.8) and spleen (17.5 ± 6.8 vs. 36.7 ± 10.3) were significantly lower (p < 0.001) and SUVmean of blood pool (1.7 ± 0.6 vs. 1.3 ± 0.3) was significantly higher (p < 0.001) in patients with SSA pre-treatment compared to patients without. No significant differences between tumour-to-liver and specific tumour-to-background SUVRs were observed between both groups (all p > 0.05).ConclusionIn patients previously treated with SSAs, a significantly lower SSR expression ([18F]SiTATE uptake) in normal liver and spleen tissue was observed, as previously reported for 68Ga-labelled SSAs, without significant reduction of tumour-to-background contrast. Therefore, there is no evidence that SSA treatment needs to be paused prior to [18F]SiTATE-PET/CT.

Keywords