Aggressive prostate cancer with somatic loss of the homologous recombination repair gene FANCA: a case report

BACKGROUND: Precision medicine based on genomic analysis of germline or tumor tissue is attracting attention. However, there is no consensus on how to apply the results of genomic analysis to treatment. CASE PRESENTATION: A 59-year-old man diagnosed with metastatic prostate cancer was diagnosed with castration-resistant prostate cancer. Although he was sequentially treated with enzalutamide and abiraterone, bone metastasis progression was identified by skeletal scintigraphy. Therefore, we sequentially performed docetaxel therapy followed by cabazitaxel. After the third cycle of cabazitaxel, his prostate-specific antigen level was stable at < 10 ng/mL, and no radiological progression was detected. The patient’s formalin-fixed paraffin-embedded tumor biopsy specimen underwent multiple-gene testing by next-generation sequencing, which identified a FANCA homodeletion. No significant germline mutation was observed. CONCLUSIONS: We describe a case of aggressive, castration-resistant prostate cancer with FANCA homodeletion. Genomic analysis of prostate cancer tissue can be useful to determine optimal treatment of such cancers.