[Positron emission tomography with computed tomography/magnetic resonance imaging for primary staging of prostate cancer]. / Positronen-Emissions-Tomographie mit Computertomographie/Magnetresonanztomographie für das primäre Staging des Prostatakarzinoms.

CLINICAL/METHODOLOGICAL ISSUE: Prostate cancer is the most common malignancy and the second leading cause of cancer-related death in men. Accurate imaging diagnosis and staging are crucial for patient management and treatment. The role of nuclear medicine in the diagnosis of prostate cancer has evolved rapidly in recent years due to the availability of hybrid imaging with radiopharmaceuticals targeting the prostate-specific membrane antigen (PSMA). STANDARD RADIOLOGICAL PROCEDURES: Hybrid imaging provides higher diagnostic accuracy compared to conventional imaging and has a significant impact on clinical management. Numerous radiotracers have been used in clinical applications, with PSMA ligands being the most commonly used. METHODOLOGICAL INNOVATIONS: Hybrid imaging provides higher diagnostic accuracy for lymph node and bone metastases compared to conventional imaging and has a significant impact on clinical management. PERFORMANCE: The high accuracy for primary staging in high-risk prostate cancer using PSMA ligands has led to the inclusion of PSMA positron emission tomography (PET)/computed tomography (CT) in the new German S3 guideline for primary staging of prostate cancer. PURPOSE: The aim of this article is to provide an overview of the use of PET imaging in the primary diagnosis of prostate cancer, to present the most commonly used radiotracers, and to highlight the results of recent studies.

177Lu-Prostate-Specific Membrane Antigen Therapy in Patients with Metastatic Castration-Resistant Prostate Cancer and Prior 223Ra (RALU Study).

223Ra-dichloride (223Ra) and 177Lu-prostate-specific membrane antigen (PSMA) are approved treatments for metastatic castration-resistant prostate cancer (mCRPC). The safety and effectiveness of sequential use of 223Ra and 177Lu-PSMA in patients with mCRPC are not well described. This study aimed to evaluate 177Lu-PSMA safety and efficacy in patients with mCRPC previously treated with 223Ra. Methods: The radium→lutetium (RALU) study was a multicenter, retrospective, medical chart review. Participants had received at least 1 223Ra dose and, in any subsequent therapy line, at least 1 177Lu-PSMA dose. Primary endpoints included the incidence of adverse events (AEs), serious AEs, grade 3-4 hematologic AEs, and abnormal laboratory values. Secondary endpoints included overall survival, time to next treatment/death, and change from baseline in serum prostate-specific antigen and alkaline phosphatase levels. Results: Data were from 133 patients. Before 177Lu-PSMA therapy, 56% (75/133) of patients received at least 4 life-prolonging therapies; all patients received 223Ra (73% received 5-6 injections). Overall, 27% (36/133) of patients received at least 5 177Lu-PSMA infusions. Any-grade treatment-emergent AEs were reported in 79% (105/133) of patients and serious AEs in 30% (40/133). The most frequent grade 3-4 laboratory abnormalities were anemia (30%, 40/133) and thrombocytopenia (13%, 17/133). Median overall survival was 13.2 mo (95% CI, 10.5-15.6 mo) from the start of 177Lu-PSMA. Conclusion: In this real-world setting, 223Ra followed by 177Lu-PSMA therapy in heavily pretreated patients with mCRPC was clinically feasible, with no indication of impairment of 177Lu-PSMA safety or effectiveness.

Safety and Survival Outcomes of 177Lu-Prostate-Specific Membrane Antigen Therapy in Patients with Metastatic Castration-Resistant Prostate Cancer with Prior 223Ra treatment: The RALU Study.

The radium lutetium (RALU) study evaluated the feasibility of sequential α- and ß-emitter use in patients with bone-predominant metastatic castration-resistant prostate cancer. Methods: This preplanned interim retrospective analysis investigated safety and survival outcomes with 177Lu-PSMA in patients treated with prior 223Ra. Results: Forty-nine patients were evaluated. Patients received a median of 6 223Ra injections; 59% of patients received at least 4 177Lu-PSMA cycles. Most (69%) patients received at least 4 life-prolonging therapies before 177Lu-PSMA. Common Terminology Criteria for Adverse Events grade 3-4 treatment-emergent adverse events during 177Lu-PSMA therapy and a 30-d follow-up period included anemia (18%) and thrombocytopenia (2%). Median overall survival was 12.6 mo (95% CI, 8.8-16.1 mo) and 31.4 mo (95% CI, 25.7-37.6 mo) from starting 177Lu-PSMA or 223Ra, respectively. Conclusion: 177Lu-PSMA treatment was well tolerated in patients who had received prior 223Ra. 223Ra use before 177Lu-PSMA is feasible and can be considered for future assessment of the optimal treatment sequence.