Real-world Clinical Outcomes and Prognostic Factors in Neuroendocrine Prostate Cancer.

Background: Neuroendocrine prostate cancer (NEPC) encompasses pure NEPC and tumors with mixed adenocarcinoma and neuroendocrine histology. While NEPC is thought to confer a poor prognosis, outcome data are sparse, making risk stratification and treatment decisions difficult for clinicians.

Methods: This retrospective study identified patients with morphological and/or immunohistochemical NEPC features on pathological review of high-grade prostate cancer cases. Median overall survival (OS) was calculated by stage and castration sensitivity. Prognostic factors were assessed via multivariate analysis. OS and progression-free survival on first-line metastatic systemic treatment were also evaluated.

Results: Of 135 NEPC cases, 25.9% had NEPC documented in the original pathological report. Mixed pathology was found in 91.9% of cases. Median OS from NEPC diagnosis was 59.2, 42.3, 14.3, 17.6 and 9.6 months for localized, nonmetastatic castration-sensitive, nonmetastatic castration-resistant, metastatic castration-sensitive and metastatic castration-resistant prostate cancer, respectively. Anemia (hazard ratio [HR]: 1.66; 95% CI 1.05-2.16; P = .031) and elevated neutrophil-lymphocyte ratio (NLR) (HR: 1.51; 95% CI 1.01-2.52; P = .045), were associated with increased risk of death on multivariate analysis. 67 patients received first-line metastatic treatment beyond androgen deprivation, with a median progression-free survival of 5.2 months and OS of 15 months. Of these, 50.7% received more than 1 line of systemic treatment.

Conclusion: We observed underdiagnosis of NEPC in pathology specimens. NEPC is associated with poorer prognosis than would be expected in pure adenocarcinoma populations, with rapid progression on first-line metastatic treatment and sharp drop-off between subsequent treatment lines. Anemia and elevated NLR were associated with poor survival.