Page 110 - New epidemiological and PSMA-expression based paradigms in salivary gland tumors

Chapter 6
Several aspects of PSMA PET imaging require further investigation, such as tissue inhomogeneity and subsequent prediction of response to treatments. Recently, different studies have reported tumor heterogeneity levels, determined on FDG PET/CT alone or combined with MRI, to be significantly associated with survival and responsiveness to radiotherapy. When a comparable determination of metabolic prognosticators in normal tissues would be possible with PMSA PET/CT, treatment plans could be optimized to further reduce toxicity to the salivary glands [33,34]. When a relation of PSMA-ligand uptake with the remaining number of vital glandular cells or actual glandular function after treatment can be determined, PSMA PET/ CT could also be used to locally assess salivary gland toxicity after external beam readiotherapy or radionuclide treatment. Moreover, equivalent to prostate cancer, PSMA-ligand uptake suggests the possibility of adjuvant treatment with 177Lu labeled PSMA in selected salivary gland cancer cases [35]. Finally, PSMA PET/CT may also play a future role in the diagnosis and treatment evaluation of benign salivary gland disease such as the sicca syndromes and recurrent plunging ranula.
Conclusions
PSMA PET/CT consistently depicts high tracer uptake in healthy major and minor salivary glands as well as lacrimal and seromucous glands. Minor salivary and seromucous glands can now be selectively visualized on imaging. Potential clinical applications of PSMA-ligand visualized by PET/CT include quantification of present salivary gland tissues and individualization of head and neck cancer treatment by radiotherapy field adaptation and 177Lu-PSMA radionuclide treatment of salivary gland cancers.
Supplementary data related to this article can be found at https://www. oooojournal.net/article/S2212-4403(18)30047-6/fulltext
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