Detection of Estrogen Receptors in Meningiomas Using FES PET-CT Scans, a Pilot Study National Institute of Neurology and Neurosurgery , Mexico  City, Mexico  National Autonomous University of Mexico  Norma Elizabeth Vázquez Estrada , MD. Sergio Moreno Jímenez, MD. Laura Hernández Sánchez, MD.

INTRODUCTION Tumors derived from meningeal arachnoid cells. Females, age 50 to 60 years 30% of intracranial tumors in adults. WHO classification grades I to III; 1% to 3% can be aggressive. 1,2  Hormonal receptors previously reported. PR in 70% , ER 40%  (ER –β) 33.3% 3,4

Diagnosis Treatment Follow up Diagnosis: CT Scan, MRI, Pathology Treatment: Active observation, surgical resection, radiation therapy. Hard to distinguish between scar or recurrence Tumours close to the bone or in the skull base.

[l8F] Fluoro-17beta-estradiol (FES) PET PET Positron Emission Tomography Radiotracers FDG, DOTATOC 6 The [l8F] Fluoro-17beta-estradiol ([18F]FES)   Breast and endometrial cancer Similar metabolism to estradiol. 7  Image via Wikimedia Commons

RESEARCH QUESTION Is it possible to Identify the presence of estrogen receptors in human meningiomas using [ [18F] FES PET CT scans? Is it feasible to conduct further formal studies using [18F] FES PET CT scans in human meningiomas?

MATERIALS AND METHODS External pilot study. Five subjects with previous diagnosis of Meningioma (2 males, 3 females) Exclusion criteria: Hormonal therapy,  <18, no previous diagnosis, lactating and pregnant women.

Nuclear Medicine interpretation Informed consent  Radiotracer synthetized in the National Autonomous University of Mexico. Nuclear Medicine service at our institution. Injection of (6.1 mci) FES  PET/CT Siemens Biograph mCT 64 Recruitment FES PET  Nuclear Medicine interpretation

Follow Up Surgery Standard Pathology T/NT (ratio of tumor activity to that of normal tissue) SUV (standardized uptake value) 30 min after tracer intake. Six months follow up, new surgical resection.  Standard Pathology  Follow Up   Surgery  Standard Pathology

RESULTS Positive uptake of [18F]FES tracer by the tumor in the five patients included. No adverse effects during the scan or  following 6 months. Pathology reports confirmed a meningioma diagnosis

Subject Age Localization of regional uptake maxSUV index Max T/NT Pathology 1 72 Anterior Falx Cerebri 1.76 5.10 Meningioma GI  2 60 Right Temporal 2.4 5.20 Meningioma GI 3 73 Left Greater  sphenoidal wing 1.85 5.13 Meningioma GII 4 58 Middle Falx Cerebri 2.0 5.17 5 57 Parasagital and right middle fossa 1.8 5.15 Meningioma GIII 3 GI Meningiomas 1 GII Meningioma  1 GIII Meningioma Average Age: 64 years Average maxT/NT:  5.15 Average maxSUV Index: 1.96

Figure 1: 58 years old male.  CT scan (a) [18F]FES PET (b) and fused PET/CT (c) images of a falx meningioma with tracer uptake of the lesion. Figure 1: A B C

CONCLUSION  A positive tumor uptake was demonstrated in the five patients, this could mean a correlation between the presence of ER and our imaging findings, however, further validation in larger studies is needed. It is feasible to perform further formal studies using FES PET scans in Meningiomas. 

DISCUSSION Small sample size, poor external validity. Immunochemistry and control group needed. Studies are needed to establish the normal biodistribution of the [18F]FES tracer in the human brain. 

FUTURE PERSPECTIVE Opens the gate to the conduction of formal studies using [18F]FES PET CT to detect the presence of estrogen receptors in meningiomas. Understanding the role of estrogen receptors in meningiomas would allow to create new therapies and prognosis.

REFERENCES 1 Fathi A-R, Roelcke U. Meningioma.Current Neurology and Neuroscience Reports. 2013;13(4). doi:10.1007/s11910-013-0337-4. 2 Saraf S, Mccarthy BJ, Villano JL. Update on Meningiomas. The Oncologist. 2011;16(11):1604-1613. doi:10.1634/theoncologist.2011-0193. 3 Wahab M, Al-Azzawi F. Meningioma and hormonal influences. Climacteric. 2003;6(4):285-292. doi:10.1080/713605429. 4 Liu M, Zhang K, Zhao Y, Guo Q, Guo D, Zhang J. Evidence for involvement of steroid receptors and coactivators in neuroepithelial and meningothelial tumors. Tumor Biology. 2014;36(5):3251-3261. doi:10.1007/s13277-014-2954-1. 5 Valotassiou V, Leondi A, Angelidis G, Psimadas D, Georgoulias P. SPECT and PET Imaging of Meningiomas. The Scientific World Journal. 2012;2012:1-11. doi:10.1100/2012/412580. 6 DOTATOC PET/CT and contrast-enhanced MRI. European Journal of Nuclear Medicine and Molecular Imaging. 2012;39(9):1409-1415. doi:10.1007/s00259-012-2155-3. 7 Sundararajan L, Linden HM, Link JM, Krohn KA, Mankoff DA. 18F-Fluoroestradiol. Seminars in Nuclear Medicine. 2007;37(6):470-476. doi:10.1053/j.semnuclmed.2007.08.003.