Treatment Outcomes in Neuroendocrine Prostate Cancer.

Abstract

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. 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. 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). 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.