PSMA-PET Imaging for Advanced ACC/SDC

Rationale: PSMA is a transmembrane protein, which is expressed on prostate cancers cells, ACC and other malignancies. In prostate cancer, distant metastases can be visualized sensitively and non-invasively with 68Ga-PSMA-PET/CT scans and if the uptake of 68Ga is high enough, patients can be treated with the β-emitting radionuclide 177Lu-PSMA. In the current study, we will evaluate the uptake of 68Ga-PSMA by performing 68Ga-PSMA-PET/CT scans in advanced ACC and SDC patients. If the uptake is high enough, this will form the rationale for a therapeutic study with 177Lu-PSMA in ACC and SDC.

Objective: The primary objective is to evaluate the uptake of 68Ga-PSMA in locally advanced, recurrent and metastatic ACC/SDC by performing 68Ga-PSMA-PET/CT scans. The secondary objectives are to calculate the SUV tumor-to-background ratio and tumor-to-'healthy salivary gland tissue' ratio. To correlate the SUV to the degree of immunohistochemical PSMA expression of the primary tumor on archival tissue, and to establish whether new metastatic lesions are found by 68GA-PSMA-PET/CT imaging.

Study design: Diagnostic study which evaluates the level of PSMA expression in ACC/SDC patients with 68Ga-PSMA-PET/CT imaging in order to establish whether these patients are eligible for 177Lu-PSMA therapy.

Study population: Patients with locally advanced, recurrent or metastatic ACC/SDC of ≥18 years old.

Inclusion criteria

• locally advanced, recurrent or metastatic ACC/SDC
• Age ≥ 18 years old
• Ability to provide written informed consent

Exclusion criteria

• Contra-indication for PET imaging
• Pregnancy
• Breast feeding
• Severe claustrophobia
• Impaired renal function: MDRD <30 ml/min/1,73 m2
• Impaired liver function: AST and ALT ≥ 2.5 x ULN (≥5 x ULN for patients with liver metastases)