Prostate-Specific Membrane Antigen Expression in Primary Juvenile Nasal Angiofibroma—A Pilot Study

Abstract

Purpose Prostate-specific membrane antigen (PSMA) is highly expressed in prostate cancer cells and is exploited for imaging and treatment of patients with prostate cancer. Prostate-specific membrane antigen expression is also demonstrated in the tumor-associated neovasculature endothelium. Juvenile nasal angiofibroma (JNA), being a similar highly vascular tumor, may also demonstrate significant PSMA expression, which may be utilized for its imaging and treatment. Methods In this prospective study, 25 clinicoradiologically diagnosed primary JNA patients underwent PSMA PET/CT scan. The scan was performed after 45 to 60 minutes of intravenous injection of 2 to 3 mCi (74–111 MBq) of 68Ga-PSMA-HBED-CC on a dedicated PET/CT scanner. Low-dose CT scan was acquired from vertex to sternoclavicular joint (100 mA, 20 kVp, 3-mm slice thickness, 0.8 pitch). Images were reconstructed with iterative reconstruction technique (4 iterations, 24 subsets). The objective was to assess the intensity and pattern of PSMA uptake in primary JNA patients. Results All cases (n = 25) of primary JNA showed PSMA expression in the tumor (100%). The median PSMA SUVmax ratio of tumor to background was 4.57 (range, 2.08–7.27). Intracranial extension in 14 of 25 patients was prominently visualized because of absence of background uptake in the brain. Advanced stage tumors demonstrated greater uptake than early tumors (P = 0.011). A statistically nonsignificant trend was noted for decreasing uptake with increasing age after normalizing for stage (Spearman correlation coefficient r = −0.08). Conclusions Assessment of PSMA expression in JNA by PSMA PET/CT opens up a new window of opportunity with respect to its radiological staging, vascularity assessment, and molecular characterization. A potential role in identification of the difficult residual-recurrent disease is anticipated and perhaps also in radioligand therapy for residual/recurrent JNA. Clinical Trials Registry of India (CTRI/2018/08/015479).

68Ga DOTANOC PET/CT Scan in Primary Juvenile Nasopharyngeal Angiofibroma ‐ A Pilot Study

“…In the study by Gronkiewicz et al using DOTATATE PET/CT, SUVmax tumor values (range, 3.6–6.4) were lower compared to our SUVmax ratio of tumor to background values (range, 3.8–9.5) 6 . Similarly, the PSMA SUVmax tumor to background ratio (range, 2.1–7.3) was lower compared to DOTANOC SUVmax (range, 3.8–9.5) 11 . These results indicate the superior uptake of DOTANOC in JNA compared to DOTATATE and PSMA PET/CT, which are the other only available functional imaging modality available as of now.…”

“…In our previous pilot study using PSMA, which was predicated on neovascularization and endothelial cells, PSMA PET/CT scan demonstrated greater activity in larger tumors and younger patients ( P = .01) 11 . However, there was no difference in DOTANOC uptake between early‐stage I/II tumors and advanced‐stage III tumors ( P = .47).…”

“…The imaging protocol was similar to our previous pilot study on JNA using the prostate‐specific membrane antigen as a tracer (Supporting Figure 1). 11 The scan was performed after 45 to 60 minutes of intravenous injection of 2 to 3 mCi (74–111 MBq) of 68 Ga‐[DOTA, 1‐Nal3]‐octreotide on a dedicated PET/CT scanner (Biograph mCT 64; Siemens Inc, Erlangen, Germany). As the disease was benign and to limit the radiation exposure a whole‐body scan was avoided and a low dose head and neck spot CT scan was acquired from vertex to sternoclavicular joint.…”

“…Anatomical/structural CEMRI and/or CECT are often incapable of precisely demarcating residual/recurrent disease from post‐surgical healing tissues while the functional scan targeting the tumor receptors aids this differentiation with ease. Prostate specific membrane antigen (PSMA) has physiological uptake in various sites in the head and neck like the salivary, the lacrimal glands, and the Eustachian tube 11 . In contrast, only the pituitary gland has the DOTANOC uptake in the head and neck and hence, the interpretation with the DOTANOC scan is visually much simpler.…”

Improve the Biodistribution with Bulky and Lipophilic Modification Strategies on Lys-Urea-Glu-Based PSMA-Targeting Radiotracers

“…PSMA, also known as glutamate carboxypeptidase II, is a transmembrane protein with an extracellular ligand binding domain. The bound ligand–protein complex is internalized via receptor-mediated clathrin-dependent endocytosis . PSMA is overexpressed up to 1000-fold higher in primary and metastatic lesions of prostate cancer than in normal tissues or organs such as kidneys, small intestine, or brain. , Having these intriguing characteristics, PSMA has become a well-established target for diagnostic and therapeutic applications with suitable radiolabeled anti-PSMA tracers. , …”