The European Association of Urology guidelines include the lutetium-177 (¹⁷⁷Lu) PSMA-617 prostate-specific membrane antigen (PSMA) ligand as a therapy option for metastatic castration-resistant prostate cancer (mCRPC). A major challenge in clinical practice is to pursue a personalized treatment approach based on robust predictive biomarkers. To assess the performance of ¹⁷⁷Lu PSMA in real-world practice and to elaborate clinical biomarkers for evaluating treatment responses. We conducted a retrospective observational study including 233 patients with mCRPC treated with ¹⁷⁷Lu PSMA in eight high-volume European centers. Baseline characteristics and clinical parameters during and after ¹⁷⁷Lu PSMA treatment were documented. Correlations to treatment response were analyzed using χ² and log-rank tests, with differences between groups with and without disease progression calculated using a Mann-Whitney U test. Univariate and multivariate-adjusted hazard ratios (HRs) were measured using Cox proportional hazards models. A prostate-specific antigen (PSA) decrease of ≥30% was observed in 41.7%, 63.5%, and 77.8% of patients after the first, second, and third treatment cycle, respectively. Restaging performed via PSMA positron emission tomography-computed tomography revealed that 33.7% of patients had an imaging-based response, including two patients with a complete response, while 13.4% had stable disease. The median time to progression was 5 mo and the median time until the start of a consecutive antineoplastic therapy was 8.5 mo. Of importance, a PSA decrease ≥30% after the first two cycles of ¹⁷⁷Lu PSMA (1 cycle: p = 0.0003; 2 cycles: p = 0.004), absolute PSA after the first three cycles (1 cycle: p = 0.011; 2 cycles: p = 0.0005; 3 cycles: p = 0.002), and a PSA doubling time >6 mo (p = 0.009) were significantly correlated to treatment response. Furthermore, gamma-glutamyl transferase ≤31 U/L at the start of ¹⁷⁷Lu PSMA therapy was correlated with 1.5 times higher risk of progression for patients without but not with visceral metastases (p = 0.046). ¹⁷⁷Lu PSMA is an effective treatment option in mCRPC in the real-world setting. A PSA decrease ≥30% after the first two cycles is an early marker of response that can be easily implemented in clinical practice. ¹⁷⁷Lu PSMA is a radioactive agent approved for treatment of advanced prostate cancer. We reviewed its use outside of clinical trials for patients treated at eight European centers. We found that ¹⁷⁷Lu PSMA is an effective treatment option in real-world practice. A PSA (prostate-specific antigen) decrease of ≥30% after the first two therapy cycles is an early indicator of response to treatment and can be used in personalizing treatments for patients.

The expanded use of second-generation antiandrogens revolutionized the treatment landscape of progressed prostate cancer. However, resistances to these novel drugs are already the next obstacle to be solved. Various previous studies depicted an involvement of the enzyme AKR1C3 in the process of castration resistance as well as in the resistance to 2nd generation antiandrogens like enzalutamide. In our study, we examined the potential of natural AKR1C3 inhibitors in various prostate cancer cell lines and a three-dimensional co-culture spheroid model consisting of cancer cells and cancer-associated fibroblasts (CAFs) mimicking enzalutamide resistant prostate cancer. One of our compounds, named MF-15, expressed strong antineoplastic effects especially in cell culture models with significant enzalutamide resistance. Furthermore, MF-15 exhibited a strong effect on androgen receptor (AR) signaling, including significant inhibition of AR activity, downregulation of androgen-regulated genes, lower prostate specific antigen (PSA) production, and decreased AR and AKR1C3 expression, indicating a bi-functional effect. Even more important, we demonstrated a persisting inhibition of AR activity in the presence of AR-V7 and further showed that MF-15 non-competitively binds within the DNA binding domain of the AR. The data suggest MF-15 as useful drug to overcome enzalutamide resistance.

Background: This study was conducted in order to analyze factors predicting malignancy in patients undergoing organ-sparing surgery (OSS) for small testicular lesions. Methods: Patients with small (≤20 mm) marker-negative clinical stage I testicular tumors were managed by OSS with tumor enucleation and frozen section examination (FSE) for the past 15 years at our institution. Benign and malignant cases were compared, focusing on preoperative and postoperative lesion sizes. Results: Eighty-nine patients were enrolled in this retrospective study. Ten (11.2%) of them were treated for synchronous bilateral tumors. Sixty-seven (67.7%) of ninety-nine lesions were benign, confirming a high concordance rate (98%) between FSE and final histology. Patients with benign tumors were significantly older than patients with malignant tumors (p = 0.026), and benign tumors were detected more frequently during urologic work-up of hormone disorders (p = 0.001). Preoperative tumor size was a strong predictor of malignancy (area under the curve (AUC) = 0.726; p < 0.001). According to the Youden index, the best cutoff to predict tumor dignity was 13.5 mm, resulting in a sensitivity and specificity of 53% and 85%, respectively. No cases of local recurrence or distant metastasis were confirmed after a median follow-up of 42 months. Conclusion: Our findings are consistent with previous reports, supporting an OSS approach in small testicular tumors whenever possible. Most tumors ≤ 20 mm were benign, and in the case of malignancy, OSS with FSE and consecutive orchiectomy is oncologically safe due to the high concordance rate of FSE and final histology, thus preventing a two-stage procedure.

Statins have been shown to improve survival of metastatic prostate cancer (mPCa). Nevertheless, their therapeutic use is still under debate. In the present study, we investigated the short-term effects of three different statins (simvastatin, atorvastatin and rosuvastatin) in various PCa cell lines mimicking androgen-sensitive and -insensitive PCa. Moreover, we generated three new PCa cell lines (LNCaPsim, ABLsim, PC-3sim) that were cultured with simvastatin over several months. Our data showed that the three statins expressed highly diverse short-term effects, with the strongest growth-inhibitory effect from simvastatin in PC-3 cells and almost no effect from rosuvastatin in any of the cell lines. Long-term treatment with simvastatin resulted in a loss of response to statins in all three cell lines, which was associated with an upregulation of cholesterol and fatty acid pathways as revealed through RNA sequencing. Despite that, long-term treated cells exhibited diminished spheroid growth and significantly reduced migration capacity per se and to differentiated osteoclasts. These findings were strengthened by reduced expression of genes annotated to cell adhesion and migration after long-term simvastatin treatment. Notably, mPCa patients taking statins were found to have lower numbers of circulating tumor cells in their blood with reduced levels of PSA and alkaline phosphatase. Our data suggest that long-term usage of simvastatin hampers the metastatic potential of PCa cells and may therefore be a potential therapeutic drug for mPCa.