Prostate cancer recurring as small-cell carcinoma with a BRCA2 somatic mutation.

INTRODUCTION

Small-cell carcinoma of the prostate has a poor prognosis, and treatment options for the refractory disease are unclear.

CASE PRESENTATION: A 68-year-old man with prostate cancer was referred to our hospital. He was treated with combined androgen blockade (bicalutamide and degarelix acetate). The disease progressed to castration-resistant prostate cancer, but with additional treatment, prostate-specific antigen levels remained below 0.02 ng/mL. However, computed tomography revealed enlarged right inguinal lymph nodes; moreover, his neuron-specific enolase levels were elevated. Histopathologic analysis of a biopsied lymph node confirmed small-cell carcinoma. After administering cytotoxic chemotherapy (etoposide plus cisplatin and amrubicin), the patient temporarily improved before relapsing. After genetic testing of the biopsy specimen revealed a BRCA2 deletion, we administered the oral PARP-2 inhibitor olaparib, which has achieved partial remission for 8 months.

CONCLUSION

PARP-2 inhibition may improve the survival of patients with BRCA2-positive small-cell carcinoma of the prostate.