Injection of Botulinum Toxin for Preventing Salivary Gland Toxicity after PSMA Radioligand Therapy: an Empirical Proof of a Promising Concept.

The dose-limiting salivary gland toxicity of ²²⁵ Ac-labelled PSMA for treatment of metastatic, castration-resistant prostate cancer remains unresolved. Suppressing the metabolism of the gland by intraparenchymal injections of botulinum toxin appears to be a promising method to reduce off-target uptake. A ⁶⁸ Ga-PSMA PET/CT scan performed 45 days after injection of 80 units of botulinum toxin A into the right parotid gland in a 63-year-old patient showed a decrease in the SUVmean in the right parotid gland of up to 64% as compared with baseline. This approach could be a significant breakthrough for radioprotection of the salivary glands during PSMA radioligand therapy.
Competing Interests: Compliance with Ethical StandardsRichard P. Baum, Thomas Langbein, Aviral Singh, Mostafa Shahinfar, Christiane Schuchardt, Gerd Fabian Volk, Harshad Kulkarni declare that they have no conflict of interest.All procedures performed in this study involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the principles of the1964 Declaration of Helsinki and its later amendments or comparable ethical standards.Informed consent was obtained from the patient who was the subject of the study.