Two cases of CRPC with BRCA mutation treated by olaparib after favorable response to cisplatin

INTRODUCTION: Several prostate cancers carry homologous recombination repair mutations that respond to olaparib. Because of the mechanism, the efficacy of platinum‐based therapy can be used to predict the efficacy of poly(adenosine diphosphate‐ribose) polymerase inhibitors such as olaparib. CASE PRESENTATION: We experienced two neuroendocrine prostate cancer patients who achieved a response duration of more than 1 year with platinum‐based therapy. Case 1 had a BRCA2 mutation in the germline and case 2 had a BRCA2 mutation in a somatic chromosome only. Both patients responded well to olaparib. CONCLUSION: Cisplatin and olaparib may overlap in response due to their medicinal action. It may be useful to consider genetic testing in some CRPC patients who have responded to cisplatin.