Treatment of liver metastases of castration resistant prostate cancer with 177Lu-PSMA-617 and SIRT

Objectives: Liver metastases of metastatic castration resistant prostate cancer (mCRPC) are associated with shortened overall survival and their treatment options are limited. 177Lu-PSMA-617 (Lu-PSMA) therapy is currently administered in patients with end stage mCRPC and an increased likelihood of liver metastases. SIRT (Selective internal radiation therapy) has proven to be effective for the treatment of liver metastases and primary liver tumours. However, the efficacy of SIRT and Lu-PSMA therapy for patients with mCRPC and liver metastases has still not been concisely characterized. Methods: 32 patients referred to Lu-PSMA treatment at our department had liver metastases, but due to rapidly declining ECOG status, follow-up imaging could only be performed in the presented 11 patients. A median target dose of 6 GBq was used for Lu-PSMA therapy. SIRT was performed in 4 patients with clinically leading hepatic progress (median activity: 2.3 GBq). PSMA-PET/CT or PSMA-PET/MRI were performed prior to and after radionuclide therapies, modified RECIST criteria (version 1.1) were used for efficacy assessment. Results: The treatment with Lu-PSMA obtained heterogeneous therapy results with non-responding and responding liver metastases in the same individual (63% vs. -35% long axis diameter change, p