Treatment Outcomes of Second-Line Systemic Therapy for Neuroendocrine Prostate Cancer: A Report of Four Cases.

Neuroendocrine prostate cancer (NEPC) is a histological variant of prostate cancer and is characterized by aggressiveness and poor clinical outcomes. NEPC usually develops as a mechanism of treatment resistance in patients receiving hormone therapy for advanced prostate cancer. NEPC is sensitive to primary platinum-based chemotherapy, and has a short response duration. Second-line therapy is required in many cases, but clinical data on subsequent treatment after progression to first-line chemotherapy is limited. Here we report our experience of four cases of NEPC treated with second-line chemotherapy. Progression-free and overall survival rates were very low in three of the patients. One patient received multidisciplinary therapy using systemic and local chemotherapy and radiation therapy and survived for 24 months after initiation of second-line chemotherapy. Multidisciplinary therapy with chemotherapy and radiation is a promising option for improving the survival of patients with NEPC.

Second-Line Systemic Therapy for Highly Aggressive Neuroendocrine Prostate Cancer.

Neuroendocrine prostate cancer (NEPC) is generally an aggressive form of prostate cancer that can arise de novo or develop as a castration-resistant mechanism. While first-line platinum-based chemotherapy is effective against NEPC, its limited response duration and subsequent treatments pose significant clinical challenges. Standard second-line treatments have not been established due to the limited data available. The aim of this review was to reveal the current status of second-line therapy for NEPC. A literature search was conducted using PubMed and Web of Science and a total of 13 articles were included in this review. Prospective and retrospective studies demonstrated that treatment outcome of second-line therapy using platinum with etoposide or docetaxel was unfavorable and progression-free survival was 3 months or shorter. Amrubicin and irinotecan were also frequently used as second-line therapy, however, efficacy of these agents was modest and response duration was less than 6 months. NEPC patients with homologous recombination repair gene alterations may benefit from treatment with poly (ADP-ribose) polymerase (PARP) inhibitors. Ongoing clinical studies investigate various agents, including immune checkpoint inhibitors, molecularly targeted agents, and PARP inhibitors. With the increasing recognition and active biopsy of NEPC lesions, the number of NEPC patients is anticipated to rise. Accumulating more knowledge and experience is crucial in developing novel treatment strategies to combat this disease.