Clinicopathological characteristics and survival outcomes in neuroendocrine prostate cancer: A population-based study

OBJECTIVE: This study aimed to investigate the clinicopathological features and the survival outcomes of neuroendocrine prostate cancer (NEPC). METHODS: Within the Surveillance, Epidemiology, and End Results (SEER) database of the National Cancer Institute, we identified a total of 510 patients with NEPC between 2006 and 2015. Age-adjusted incidence rates were evaluated in the study by the SEER∗Stat Software version 8.3.6. Kaplan–Meier analysed assessed overall survival (OS) after stratification according to marital status, age, histologic subtype, metastatic status, and treatment. The significant differences were assessed in a log-rank test. Univariate and multivariate cox hazard regression analysis were performed to determine independent predictors of OS. RESULTS: From a total of 560,124 patients with prostate cancer diagnosed between 2006 and 2015, we identified 510 cases of de novo NEPC. Regarding histology, among all the NEPC, 329 (64.5%) patients were diagnosed as small cell carcinoma, 181 (39.8%) were nonsmall cell carcinoma. The overall age-adjusted incidence of NEPC statistically significantly increased from 0.321/1,000,000 person-years in 2006 to 0.587/1,000,000 person-years in 2015. The median OS in our study cohort was 9 months (95% CI, 8–10 months). Multivariate cox regression analysis showed that age, histologic subtype, and stage were independent prognostic factors for NEPC patients. The majority of NEPC (78.2%) were metastatic at diagnosis. In terms of treatment, for metastatic tumor patients, chemotherapy was the most effective therapy. Chemotherapy increased the OS of patients with regional (distant) metastases from 8 months (5 months) to 13.5 months (9 months). CONCLUSION: NEPC is extremely rare but the incidence of NEPC has been increasing in the past years. The prognosis of NEPC is poor because most cases are diagnosed at metastatic stage. The patients with metastases are typically treated with chemotherapy and chemotherapy shows survival benefits in both regional and distant metastatic tumor patients.