Direct comparison of (68)Ga-DOTA-TOC and (18)F-FDG PET/CT in the follow-up of patients with neuroendocrine tumour treated with the first full peptide receptor radionuclide therapy cycle

Bernhard Nilica; Dietmar Waitz; Vlado Stevanovic; Christian Uprimny; Dorota Kendler; Sabine Buxbaum; Boris Warwitz; Llanos Gerardo; Benjamin Henninger; Irene Virgolini; Margarida Rodrigues

doi:10.1007/s00259-016-3328-2

Direct comparison of (68)Ga-DOTA-TOC and (18)F-FDG PET/CT in the follow-up of patients with neuroendocrine tumour treated with the first full peptide receptor radionuclide therapy cycle

Eur J Nucl Med Mol Imaging. 2016 Aug;43(9):1585-92. doi: 10.1007/s00259-016-3328-2. Epub 2016 Feb 27.

Affiliations

¹ Department of Nuclear Medicine, Innsbruck Medical University, Anichstrasse 35, A-6020, Innsbruck, Austria.
² Department of Radiology, Innsbruck Medical University, Anichstrasse 35, A-6020, Innsbruck, Austria.
³ Department of Nuclear Medicine, Innsbruck Medical University, Anichstrasse 35, A-6020, Innsbruck, Austria. rodriguesradischat@hotmail.com.

Abstract

Purpose: To determine the value of (68)Ga-DOTA-TOC and (18)F-FDG PET/CT for initial and follow-up evaluation of patients with neuroendocrine tumour (NET) treated with peptide receptor radionuclide therapy (PRRT).

Methods: We evaluated 66 patients who had histologically proven NET and underwent both PRRT and three combined (68)Ga-DOTA-TOC and (18)F-FDG PET/CT studies. (68)Ga-DOTA-TOC PET/CT was performed before PRRT, 3 months after completion of PRRT and after a further 6 - 9 months. (18)F-FDG PET/CT was done within 2 months of (68)Ga-DOTA-TOC PET/CT. Follow-up ranged from 11.8 to 80.0 months (mean 34.5 months).

Results: All patients were (68)Ga-DOTA-TOC PET-positive initially and at follow-up after the first full PRRT cycle. Overall, 62 of the 198 (18)F-FDG PET studies (31 %) were true-positive in 38 of the 66 patients (58 %). Of the 66 patients, 28 (5 grade 1, 23 grade 2) were (18)F-FDG-negative initially and during follow-up (group 1), 24 (5 grade 1, 13 grade 2, 6 grade 3) were (18)F-FDG-positive initially and during follow-up (group 2), 9 patients (2 grade 1, 6 grade 2, 1 grade 3) were (18)F-FDG-negative initially but (18)F-FDG-positive during follow-up (group 3), and 5 patients (all grade 2) were (18)F-FDG-positive initially but (18)F-FDG-negative during follow-up (group 4).(18)F-FDG PET showed more and/or larger metastases than (68)Ga-DOTA-TOC PET in five patients of group 2 and four patients of group 3, all with progressive disease. In three patients with progressive disease who died during follow-up tumour SUVmax increased by 41 - 82 % from the first to the last follow-up investigation.

Conclusion: In NET patients, the presence of (18)F-FDG-positive tumours correlates strongly with a higher risk of progression. Initially, patients with (18)F-FDG-negative NET may show (18)F-FDG-positive tumours during follow-up. Also patients with grade 1 and grade 2 NET may have (18)F-FDG-positive tumours. Therefore, (18)F-FDG PET/CT is a complementary tool to (68)Ga-DOTA-TOC PET/CT with clinical relevance for molecular investigation.

Keywords: 18F-FDG; 68Ga-DOTA-TOC; NET; PET/CT; PRRT.

Publication types

Comparative Study

MeSH terms

Adult
Aged
Biological Transport
Female
Fluorodeoxyglucose F18* / metabolism
Follow-Up Studies
Humans
Male
Middle Aged
Neoplasm Staging
Neuroendocrine Tumors / diagnostic imaging*
Neuroendocrine Tumors / metabolism
Neuroendocrine Tumors / pathology
Neuroendocrine Tumors / radiotherapy*
Octreotide / analogs & derivatives*
Octreotide / metabolism
Organometallic Compounds* / metabolism
Positron Emission Tomography Computed Tomography*
Receptors, Somatostatin / therapeutic use*
Retrospective Studies

Substances

Ga(III)-DOTATOC
Organometallic Compounds
Receptors, Somatostatin
Fluorodeoxyglucose F18
Octreotide