Gallium-68-somatostatin receptor PET/CT parameters as potential prognosticators for clinical time to progression after peptide receptor radionuclide therapy: a cohort study

Sander C Ebbers; Muriël Heimgartner; Maarten W Barentsz; Rachel S van Leeuwaarde; Mark J C van Treijen; Marnix M E G Lam; Arthur J A T Braat

doi:10.1186/s41824-021-00116-z

Gallium-68-somatostatin receptor PET/CT parameters as potential prognosticators for clinical time to progression after peptide receptor radionuclide therapy: a cohort study

Eur J Hybrid Imaging. 2021 Dec 9;5(1):22. doi: 10.1186/s41824-021-00116-z.

Authors

Sander C Ebbers¹, Muriël Heimgartner², Maarten W Barentsz², Rachel S van Leeuwaarde², Mark J C van Treijen³, Marnix M E G Lam², Arthur J A T Braat²

Affiliations

¹ Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. s.c.ebbers-2@umcutrecht.nl.
² Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.
³ Department of Endocrine Oncology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.

Abstract

Background: Early [⁶⁸Ga]Ga-DOTA-TOC PET/CT imaging after peptide receptor radionuclide therapy (PRRT) in neuroendocrine neoplasm patients is often used as a prognosticator for survival, but lacks validity. This study investigates the prognostic value of changes in PET parameters after PRRT.

Methods: Baseline and follow-up [⁶⁸Ga]Ga-DOTA-TOC PET/CT scans of all patients treated with PRRT were delineated automatically. Total lesion somatostatin receptor expression (TL-SSTR) and somatostatin receptor expressing tumor volume (SSTR-TV) were used as covariates in Cox proportional hazard models to predict time-to-new treatment.

Results: In twenty patients, median time-to-new treatment was 19.3 months (range [3.8; 36.2]). Absolute and percentual changes in both PET parameters were not associated with time-to-new treatment. A significant relation between independent baseline and follow-up SSTR-TV and follow-up TL-SSTR, and time-to-new treatment was identified.

Conclusions: Automatically derived [⁶⁸Ga]Ga-DOTA-TOC PET/CT parameters are easy to acquire and may be of prognostic value after completing PRRT. Acquiring SSTR-TV or TL-SSTR parameters at baseline and during follow-up can be of value in identifying a patient's prognosis.

Keywords: PET-based response; PRRT; Progression-free survival; Time-to-new treatment; [68Ga]Ga-DOTA-TOC PET/CT.