October 2021: Association of RAD51 with HRD and clinical outcomes in untreated TNBC

This study compared an immunohistology-based RAD51 test with genetic/genomic tests to identify patients with homologous recombination deficiency (HRD) primary triple-negative breast cancer (TNBC) and evaluates its accuracy to select patients sensitive to platinum-based neoadjuvant chemotherapy (NACT).

Highlights:

• In patients with TNBC, functional HRD by the RAD51 test identifies 93% of tBRCA-mutated tumors and shows 87% concordance with genomic HRD.
• RAD51 independently predicts pCR with platinum (interaction test p=0.02).
• This study supports the use of RAD51 as a clinically relevant biomarker of HRD and platinum response.

Conclusion: The RAD51 test identifies tumors with functional HRD and is highly concordant with tBRCA mutation and genomic HRD. RAD51 independently predicts clinical benefit from adding carboplatin to NACT in TNBC. Our results support further development to incorporate RAD51 testing in clinical decision-making.

Llop-Guevara A, Loibl S, Villacampa G, et al. Association of RAD51 with homologous recombination deficiency (HRD) and clinical outcomes in untreated triple-negative breast cancer (TNBC): analysis of the GeparSixto randomized clinical trial. Ann Oncol. 2021;32:1590-1596.

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