Effective treatment of relapsed prostate small cell carcinoma with amrubicin: report of a case.

Standard therapy for metastatic small cell carcinoma of the prostate (SCCP) remains undefined. We have effectively treated relapsed SCCP with amrubicin. A 72-year-old patient, diagnosed with T4N1M0 prostate cancer, started hormonal therapy in May 2012, elsewhere, and his prostate-specific antigen levels remained low. However, pulmonary and hepatic metastases occurred; high neuron-specific enolase levels suggested SCCP, which was confirmed by repeated biopsy at our institution. In October 2016, chemotherapy with irinotecan and cisplatin was initiated for metastases to the lung, liver, and left pelvic lymph nodes, and partial response (PR) was achieved. After six cycles, brain metastases occurred. After ten cycles, his pro-gastrin-releasing peptide levels increased suddenly, and brain and hepatic metastases enlarged. Amrubicin was started in December 2016 and seven cycles were safely completed, with PR and markedly reduced brain metastasis volume, until his pneumonitis-related death in June 2017. Amrubicin may be an effective second-line chemotherapy option for SCCP.