Page 159 - New epidemiological and PSMA-expression based paradigms in salivary gland tumors

-Part 2-
Molecular imaging of PSMA in salivary glands
Chapter 7:
Prostate-specific membrane antigen (PSMA) positron emission tomography/ computed tomography (PET/CT) is used for detection and (re)staging of prostate cancer. However, healthy salivary, seromucous, and lacrimal glands also have high PSMA-ligand uptake. This study aimed to describe physiologic PSMA-ligand uptake distribution characteristics in the head and neck to aid in PSMA PET/CT interpretation and to identify possible new clinical applications for PSMA-ligand imaging.
Thirty consecutive patients who underwent PSMA PET/CT for prostate cancer were evaluated. Tracer maximum standardized uptake values (SUV max) in the salivary, seromucous, and lacrimal glands were determined visually and quantitatively. Overall and intraindividual variations were reported. The scans showed that all gland locations had increased tracer uptake. The mean SUVmax ± standard deviation varied: parotid 12.3 ± 3.9; submandibular 11.7 ± 3.5; sublingual 4.5±1.9; soft palate 2.4±0.5; pharyngeal wall 4.3±1.3; nasal mucosa 3.4±0.9; supraglottic larynx 2.7±0.7; and lacrimal 6.2±2.2. The parotid had the largest overall variation in SUVmax (5.2-22.9), and the sublingual glands had the largest mean intraindividual difference (18.1%).
In conclusion, major and minor salivary and seromucous glands consistently have high PSMA-ligand uptake. Minor gland locations can be selectively visualized by this technique for the first time. This provides potential new applications such as quantification of present salivary gland tissues and individualization of radiotherapy for head and neck cancer or lutetium-177-PSMA radionuclide treatment.
Chapter 8:
10
Evaluation of salivary gland damage after head and neck radiotherapy (RT) is difficult with current tools, such as subjective patient-reported outcome measures. We demonstrate the use of prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) as an objective non- invasive tool to visualize damage to salivary glands resulting from RT. In three clinical cases, the PSMA-ligand distribution correlates to the RT dose distribution including intra-gland dose gradients and matches patient-reported toxicity,
Summary
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