Lu177-PSMA therapy for men with advanced prostate cancer: 18 months survival analysis in a single Australian tertiary institution.

INTRODUCTION: Radioligand therapies, or 'theranostics', have an emerging role in patients with metastatic castration-resistant prostate cancer (mCRPC). Lutetium-177 (Lu), targeting prostate-specific membrane antigen (PSMA), has demonstrated promising outcomes including reduced disease progression and improved overall survival. We aim to determine overall survival demonstrated by our LuPSMA patient cohort to date.
METHODS: Kaplan-Meier survival analysis and log-rank test were performed on all LuPSMA therapy patients with at least 12 months of follow-up data available (n = 68). Comparison across patients was made based on several variables including the baseline characteristics of prostate-specific antigen (PSA) level, maximum standard uptake value (SUVmax ) and metastasis site and by biochemical response.
RESULTS: The 18-month overall survival estimate for the patient cohort was 63.8%. Patients with baseline serum PSA <20 µg/L had a greater 18-month survival estimate (79.9%) compared to PSA ≥20 µg/L (53.8%; P < 0.05). Patients with an SUVmax  >15 had an 18-month survival estimate of 56.0%, compared to 38.0% in patients with SUVmax  ≤15 (P < 0.05). No significant difference in overall survival was observed by metastasis site. Both a decrease in PSA after two LuPSMA therapy cycles and the maximum response over the treatment course being a decline in PSA were indicative of greater overall survival (P < 0.01 and P < 0.001 respectively).
CONCLUSION: Our study reported an 18-month overall survival of 64% in patients with mCRPC who have undergone LuPSMA therapy. Our study identified that baseline serum PSA, SUVmax and biochemical response to treatment are prognostic markers for increased overall survival.