Metastatic castration-resistant prostate cancer (mCRPC) is the most challenging stage in prostate cancer. Patient with visceral metastasis have the poorest outcome amoung them. In this retrospective study, we analyzed the clinical outcome of lutetium-177 prostate-specific membrane antigen (177Lu-PSMA) in mCRPC patients with visceral metastasis.
Ten patients of mCRPC with visceral metastasis were enrolled for one cycle of 177Lu-PSMA therapy. Number of efficacy and safety parameters, e.g., prostate-specific antigen (PSA), visual analog scale (VAS) and analgesic quantification scale (AQS), hemoglobin (Hb), total leukocytes counts (TLC), platelets, creatinine, & total bilirubin, were assessed and compared with Wilcoxon signed-rank test. The progression-free survival (PFS) curve was computed by the Kaplan-Meier method. The receiver operating characteristic curve (ROC) was also plotted for 177Lu-PSMA dose. P≤0.05 was considered significant.
Liver (80%), lung (30%), adrenal (10%), and peritoneum (10%) were the sites of visceral metastasis in our study. On PSA response assessment, 10%, 60%, and 30% of the patients had partial response, stable disease, and progressive disease, respectively. Forty percent of the patients had improvement in the VAS, while 50% had improvement in the AQS score. Median PFS was 24 weeks in our study. A cut-off of 4.88GBq of 177Lu-PSMA was the best-predicted progression with 66.67% sensitivity and 100% specificity on ROC analysis. Thirty percent of the patients showed grade 3 anemia. No other significant toxicity was seen.
Lutetium-177-PSMA was a reasonable palliative treatment option with limited toxicity for these end-stage mCRPC patients with visceral metastasis with adequate PSA stabilization.
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