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Initial clinical experience performing sialendoscopy for salivary gland protection in patients undergoing 225Ac-PSMA-617 RLT

Abstract: 

Purpose: Main side effect of prostate-specific membrane antigene targeting alpha-therapy (PSMA-TAT) is the dry-mouth-syndrome. Inflammations of the salivary glands and consecutive reduced salivary function were already reported for patients after radioiodine therapy. Beneficial effects of sialendoscopy intervention for radiation inflammation to tissue are well known. Thus, sialendoscopy with dilatation, saline irrigation and steroid injections (prednisolone) were performed before or after 225Ac-PSMA-617-TAT to reduce inflammation effects in the salivary glands and improve or prevent xerostomia. Methods: Eleven male patients with metastatic castration-resistant prostate cancer (mCRPC) and a mean age of 68.5 years (range 58-80 y) underwent sialendoscopy, dilatation, saline irrigation and steroid injection of both submandibular and both parotid glands before or after application of 225Ac-PSMA-617-TAT for every cycle. Sialendoscopy and steroid injection was performed by an ENT senior physician. Quality of life assessment was evaluated using two health-related quality of life (HRQOL) questionnaires, the Xerostomia Questionnaire (XQ) and the Xerostomia Inventory (XI) pre- and three months postoperatively. Results: In all 11 patients both parotid- and both submandibular glands were affected due to radiation sialadenitis and sialendoscopic intervention applied. Patients treated with sialendoscopy showed a significant improvement in HRQOL measurements regarding the XQ and XI. After sialendoscopy the XQ score decreased significantly from 77.7 ± 13.6 to 42.7 ± 14.8 (p=0.003) and the XI score decreased from 44.5 ±6.9 to 25.8 ±12.8 (p=0003). Due to our limited number of patients we only describe tendencies. We did not experience any complications after sialendoscopy. Conclusions: Sialendoscopy with dilatation, saline irrigation and steroid injection had beneficial effects to the salivation function and health-related quality of life for patients under 225Ac-PSMA-617-RLT. However, even with sialadenoscopic support after multiple cycles of TAT, salivary gland function was reduced and xerostomia was present. Therefore not only the inflammation but also the direct radiation is putatively causative for the dry mouth. Further research is necessary to cope the main side effect of PSMA-TAT.