Additional Local Therapy for Liver Metastases in Patients with Metastatic Castration-Resistant Prostate Cancer Receiving Systemic PSMA-Targeted Therapy.

Abstract

The aim of this study was to evaluate the efficacy of ¹⁷⁷Lu-prostate-specific membrane antigen (PSMA)-617 (¹⁷⁷Lu-PSMA) and selective internal radiation therapy (SIRT) for the treatment of liver metastases of castration-resistant prostate cancer. <b>Methods:</b> Safety and survival of patients with metastatic castration-resistant prostate cancer and liver metastases assigned to ¹⁷⁷Lu-PSMA alone (<i>n</i> = 31) or in combination with SIRT (<i>n</i> = 5) were retrospectively analyzed. Additionally, a subgroup (<i>n</i> = 10) was analyzed using morphologic and molecular response criteria. <b>Results:</b> Median estimated survival was 5.7 mo for ¹⁷⁷Lu-PSMA alone and 8.4 mo for combined sequential ¹⁷⁷Lu-PSMA and SIRT. ¹⁷⁷Lu-PSMA achieved discordant therapy responses with both regressive and progressive liver metastases in the same patient (best vs. worst responding metastases per patient: -35% vs. +63% diameter change; <i>P</i> < 0.05). SIRT was superior to ¹⁷⁷Lu-PSMA for the treatment of liver metastases (0% vs. 56% progression). <b>Conclusion:</b> The combination of ¹⁷⁷Lu-PSMA and SIRT is efficient and feasible for the treatment of advanced prostate cancer. ¹⁷⁷Lu-PSMA alone seems to have limited response rates in the treatment of liver metastases.