Improved Detection of Postoperative Residual Meningioma with [68Ga]Ga-DOTA-TOC PET Imaging Using a High-resolution Research Tomograph PET Scanner

Abstract

Purpose: PET with somatostatin receptor ligand [ 68 Ga]Ga-DOTA-D-Phe 1 -Tyr 3 -octreotide ([ 68 Ga]Ga-DOTA-TOC) is an established method in radiotherapy planning because of the improved detection and delineation of meningioma tissue. We investigated the diagnostic accuracy of supplementary [ 68 Ga]Ga-DOTA-TOC PET in patients with a 3-month postoperative MRI reporting gross-total resection (GTR).Experimental Design: Thirty-seven patients with a histologically proven meningioma and GTR on postoperative MRI were prospectively referred to [ 68 Ga]Ga-DOTA-TOC PET. Detection and volume measurements of [ 68 Ga]Ga-DOTA-TOC-avid lesions in relation to the primary tumor site were recorded. Residual tumor in suspicious lesions suggested by [ 68 Ga]Ga-DOTA-TOC PET was verified by (i) tumor recurrence/progression on subsequent MRI scans according to the Response Assessment of Neuro-Oncology criteria, (ii) subsequent histology, and (iii) follow-up [ 68 Ga]Ga-DOTA-TOC PET scan.Results: Twenty-three PET scans demonstrated [ 68 Ga]Ga-DOTA-TOC-avid lesions suspicious of residual meningioma, where 18 could be verified by (i) tumor progression on subsequent MRI scans (n ¼ 6), (ii) histologic confirmation (n ¼ 3), and (iii) follow-up [ 68 Ga]Ga-DOTA-TOC PET scans confirming the initial PET findings (n ¼ 9) after an overall median follow-up time of 17 months (range, 9-35 months). In contrast, disease recurrence was seen in only 2 of 14 patients without [ 68 Ga]Ga-DOTA-TOC-avid lesions (P < 0.0001). The sensitivity, specificity, and diagnostic accuracy of [ 68 Ga]Ga-DOTA-TOC PET in detecting meningioma residue was 90% [95% confidence interval (CI), 67-99], 92% (95% CI, 62-100), and 90% (95% CI, 74-98; P < 0.0001), respectively.Conclusions: The majority of patients with GTR on 3-month postoperative MRI may have small unrecognized meningioma residues that can be detected using [ 68 Ga]Ga-DOTA-TOC PET.

Radiotherapy for meningiomas

“…One study correlating 68 Ga DOTATATE PET with intraoperative sampling showed greater sensitivity as compared to contrast enhanced MRI (92.3% vs 79.5% for primary and 88.1% vs 76.7% for recurrent tumors). Remarkably, in another study by Bashir et al [ 74 ], residual [ 68 ] Ga-DOTATOC PET uptake was noted after gross total resection of 23 of 37 (62%) meningiomas, as determined by standard of care MRI. Of these 23, nine (39%) were confirmed either by subsequent recurrence, or by sampling during re-operation.…”

Meningioma grading based on positron emission tomography: A systematic review and meta-analysis

“…Twelve articles were retrieved for full-text review. After exclusion of the studies 19 , 20 , 21 , 22 , 23 , 24 , 25 that did not provide data for tumor grade and also did not allow the calculation of diagnostic accuracy, five cohort studies were considered eligible for our analysis. 3 , 4 , 26 , 27 , 28 These five studies included 242 patients with a total of 196 low-grade (Grade 1) and 46 high-grade (Grade 2/3) meningiomas.…”

Postoperative [68Ga]Ga-DOTA-TATE PET/CT imaging is prognostic for progression-free survival in meningioma WHO grade 1

“…Somatostatin receptor PET imaging has been shown to be highly sensitive in detecting tumor remnant after microsurgical tumor resection in patients with intracranial meningioma [ 23 , 25 ]. However, the prognostic importance of residual tumor as indicated by [ 68 Ga]Ga-DOTA-TATE PET/CT is so far unclear.…”

“…Somatostatin receptor type 2 (SSTR2) is ubiquitously expressed in up to 100% of meningiomas and can be addressed by radiolabeled SSTR2 ligands such as [ 68 Ga]Gallium-DOTA-TATE, [ 68 Ga]Gallium-DOTA-TOC, and most recently [ 18 F]SiTATE [ 18 , 19 ]. Biopsy-controlled studies have validated SSTR2 PET/CT as a highly sensitive tool for detecting meningioma tissue and distinguishing between tumor and tumor-free tissue, which is superior to MRI [ 20 – 23 ]. This enables differential diagnosis of MR morphologically ambiguous lesions [ 24 ], provides an excellent opportunity to assess the extent of resection after surgery [ 23 , 25 ], and importantly also improves tumor delineation for radiation planning [ 26 – 29 ].…”

“…Biopsy-controlled studies have validated SSTR2 PET/CT as a highly sensitive tool for detecting meningioma tissue and distinguishing between tumor and tumor-free tissue, which is superior to MRI [ 20 – 23 ]. This enables differential diagnosis of MR morphologically ambiguous lesions [ 24 ], provides an excellent opportunity to assess the extent of resection after surgery [ 23 , 25 ], and importantly also improves tumor delineation for radiation planning [ 26 – 29 ]. In this context, new grading systems for EOR incorporating postoperative PET/CT or PET/MRI findings have already been proposed, but prospective validation is still lacking, and prognostic relevance of postoperative SSTR2 PET/CT for tumor recurrence ultimately remains unclear [ 30 ].…”