Real-World Outcomes Of Lu-177 PSMA In Patients With Metastatic Castration-Resistant Prostate Cancer: A Retrospective Single-Center Experience

Abstract Aim: This studyaimed to assess the influence of laboratory and clinicopathological features on survival and treatment response as well as the importance of uptake changes in PSMA-PET-CT after Lutetium-177-PSMA treatment in metastatic castration-resistant prostate cancer(mCRPC). Material-Method: Totally,38 men with mCRPC who received Lu-177 )at a dose of 4.0 to 6.8 GBq with a mean of 5.5 GBq once every six or nine weeks for 1 to 6 cycles (median 3) were included in this study. PSMA PET with computed tomography was performed for response evaluation. Pre and post-treatment laboratory and imaging findings were obtained from patients’ charts and analyzed retrospectively. Results : At a median follow-up of 12.2 months, the median PFS and OS were 5.8 and 12.3 months, respectively. The objective response rate was 36.8%. Any grade and grade3/4 toxicity rates were as follows:86.8%(n=33) and57.9%(n=22).The presence of visceral metastasis, ALP, PSA, and SUVmax values were significant prognostic factors for PFS.The SUVmax value of <4 after treatment was an independent significant factor for PFS in multivariate analysis (p=0.002; HR:6.6,95%CI 2.03-22.00). The significant prognostic factors for OS were previous treatment lines, presence of visceral metastasis, ECOG PS PSA and ALP values, and median SUV max value after treatment.The multivariate analysis for OS indicated that ECOG PS (p=0.01, HR:16.7, 95%CI 1.58-176.32), pre LU-177-PSMA ALP values (p=0.05;HR:0.96,95% CI 0.93-1.00),post Lu-177 PSA values(p=0.02;HR:1.01,95%CI1.00-1.03)and SUV max value p=(0.005;HR:6.6,95%CI1.74-25.1)were independent prognostic factors. Conclusion: ECOG PS, baseline ALP values, PSA response, and SUV response of the target lesion were the independent prognostic factors for OS. Thus Lu-177-PSMA is an effective option with a good safety profile in second and later lines of treatment for patients with mCRPC.