Treatment Outcomes in Neuroendocrine Prostate Cancer

Abstract

Background/aim: Neuroendocrine prostate cancer (NEPC) is rare and has a poor prognosis; its clinical course and treatment outcomes are also unclear. This study investigated the clinical characteristics, clinical course, and treatment outcomes of patients with NEPC.

Patients and methods: This retrospective study investigated 14 patients histologically diagnosed with NEPC at Kanazawa University Hospital between 2000 and 2019. Overall survival (OS) and progression-free survival (PFS) were retrospectively analyzed using the Kaplan-Meier method. Additionally, log-rank tests were used to compare survival distributions.

Results: We included 14 patients histologically diagnosed with NEPC among 1,845 patients with prostate cancer. Four patients (0.22%) were diagnosed with de novo NEPC, and ten patients were diagnosed with NEPC during treatment. First-line platinum-based therapy's objective response rate (ORR) was 66.7%, and disease control rate was 91.7%; median PFS was 7.5 months. The median OS from NEPC diagnosis was 20.3 months. The median OS of the liver metastasis (-) group was 31.6 months, and that of the (+) group was 9.4 months (p=0.03, hazard ratio=0.24). The median OS of the somatostatin receptor scintigraphy (SRS)-positive group was 31.6 months, and that of the SRS-negative group was 10.6 months (p=0.04, hazard ratio=0.14).

Conclusion: Platinum-based chemotherapy is effective to some extent, but the duration of response is not sufficient; therefore, new treatment options are needed. This is the first study to show that SRS findings and the presence of liver metastases might be prognostic predictors of NEPC.

Keywords: Neuroendocrine prostate cancer; liver metastasis; prostate cancer; small cell carcinoma; somatostatin receptor scintigraphy.