Diagnosis of Adenoid Cystic Carcinoma on 68Ga-PSMA-617 PET-CT and Therapy With 177Lu-EB-PSMA-617

Adenoid cystic carcinoma (ACC) is a rare tumor entity with a yearly incidence of 3-5 cases per million. ACC arises in the major salivary glands and more often in the minor salivary glands of the oropharynx, lip, nasopharynx, oral cavity, nasal cavity, paranasal sinus, larynx and tracheobronchial tree. ACC is characterized by frequent local recurrences and distant metastasis, mainly to lungs. 18F-FDG PET/CT is considered to be a viable tool to assess ACC at initial presentation. However, FDG uptake in ACC is lower than in squamous cell carcinoma (SCC) and not all ACC lesions show detectable FDG uptake. So, it is necessary to find another effective way to detect ACC and its metastases. As in known, PSMA is highly expressed in salivary glands, and Wim van Boxtel et al had demonstrated high PSMA-ligand uptake in a patient with recurrent and metastatic ACC using 68Ga-PSMA PET/CT. 68Ga-PSMA has been developed as a targeting imaging agent widely used in prostate cancer in prostate cancer. Thus, this prospective study is going to investigate whether 68Ga-PSMA PET/CT may be superior for diagnosis, therapy response assessment and follow-up of ACC than 18F-FDG PET/CT. Furthermore, peptide receptor radionuclide therapy has been widely used in the treatment of prostate cancer lesions that showed high PSMA uptake on 68Ga-PSMA PET/CT, we'll try to assess the safety and therapeutic response to 177Lu-EB-PSMA-617 in patients with ACC.