A 63-year-old man with a significantly high prostate-specific antigen level was diagnosed via pathology to have advanced prostate adenocarcinoma due to multiple lung metastases. He was then treated with androgen deprivation therapy (ADT) comprising bicalutamide and goserelin. Only after 6 months of stable disease, the cancer progressed and the drug was changed to abiraterone; however, no significant therapeutic effect was observed and the disease was considered as castration-resistant prostate cancer. The histopathologic analysis of the biopsied metastatic lymph node confirmed small-cell neuroendocrine carcinoma, and genetic testing revealed BRCA1 germ-line mutation. The oral PARP inhibitor olaparib was used and achieved a partial tumor response over a period of 2.5 months. Meanwhile, palliative radiotherapy was performed for pain control in the sacrococcygeal region with complete symptom relief. The combination chemotherapy strategy of etoposide and cisplatin was used after the failure of olaparib and achieved pain alleviation in the left leg. The patient received one cycle of this chemotherapy strategy and eventually died of a rapid tumor progression, respiratory failure, and heart failure on April 27, 2019.