Outcome of ¹⁷⁷Lu-PSMA Radionuclide Treatment in Advanced Prostate Cancer and Its Association with Clinical Parameters: A Single-Center Experience

Purpose This study was set out to analyze the efficacy and safety of 177Lu-PSMA-617 (LuPSMA) treatment in metastatic castration-resistant prostate cancer (mCRPC) patients. Patients and Methods Progressive mCRPC patients who received at least 1 cycle of LuPSMA therapy were evaluated retrospectively. Demographic, clinic, and histopathological data were documented. Treatment efficacy was determined based on biochemical response criteria (Prostate Cancer Clinical Trial Working Group 3), and toxicity rates were defined based on CTCAE v4.03. The prognostic significance of laboratory/clinical data and 68Ga-PSMA PET/CT quantitative results were analyzed using SPSS Version 24.0. Results One hundred patients (median prostate-specific antigen [PSA] level, 75.7 ng/mL) who met the eligibility criteria were identified. The median number of cycles received per patient was 3 (range, 1-9). After the first cycles of LuPSMA, biochemical partial response, biochemical stable disease, and biochemical progressive disease were observed in 31%, 36%, and 33% of patients, respectively. Any PSA decline was determined in 60% of patients. After the fourth cycle of treatment, biochemical partial response, biochemical stable disease, and biochemical progressive disease were defined in 48%, 26%, and 26% of patients, respectively. The median overall survival (OS) from the first cycle of LuPSMA was 14 months. Patients who had any PSA response after the first cycle had significantly longer OS than nonresponders (median OS: 17 vs 9 months; P ≤ 0.001). Total PSMA-derived tumor volume (P = 0.004), total PSMA activity per lesion (P = 0.01), PSA (P = 0.007), alkaline phosphatase (P = 0.002), lactate dehydrogenase (P < 0.001), and hemoglobin (P < 0.001) were significant prognostic factors for OS in univariate Cox regression analysis. Conclusions LuPSMA therapy is a favorable treatment for mCRPC with remarkable therapeutic efficacy and low toxicity rates, even in progressive disease under standard therapies. Baseline PSMA-based tumor burden, PSA, alkaline phosphatase, lactate dehydrogenase, and hemoglobin were significant predictors of OS and can be useful for selection of the best candidate for LuPSMA therapy.