The benefit of PARPi has been well established for ovarian (SOLO-1 study) and prostate cancer (PROFOUND study) with defects in the Homologous Recombination Repair (HRR) system due to BRCA1 or BRCA2 variants. Somatic variants in HRR genes are currently researched by Next Generation Sequencing (NGS). However, in metastatic prostate cancer, using formalin-fixed and paraffin-embedded (FFPE) samples, failure rate is around 30 % according to our retrospective datas, in agreement with the data of the PROFOUND study, highlighting a real pre-analytical matter when FFPE samples are used for NGS testing. Research of such alterations on circulating tumor DNA (ctDNA) extracted from plasma or urine could be a promising alternative test.
