13 Jun 2025
In the evolving landscape of ovarian cancer treatment, homologous recombination deficiency (HRD) testing plays a vital role in guiding personalized care. Although HRD testing has the potential to inform maintenance therapy selection, real-world data demonstrate that it remains underutilized-resulting in many patients never being assessed for potential eligibility for targeted therapy. Expanding the use of HRD testing could significantly enhance outcomes for patients with epithelial ovarian, fallopian tube, and primary peritoneal cancers. HRD refers to a tumor’s inability to effectively repair double-stranded DNA breaks through the homologous recombination repair (HRR) pathway. When HRR is compromised, tumor cells rely on alternative, error-prone repair mechanisms, leading to genomic instability—a hallmark of cancer. Approximately 50% of advanced ovarian cancer cases exhibit HRD, making it a critical biomarker for selection of maintenance therapies.
HRD can arise due to BRCA1/2 mutations, as well as alterations in other HRR pathway genes such as RAD51C, RAD51D and ATM. These genetic changes create vulnerabilities that targeted therapies can exploit. HRD status is particularly relevant in predicting response to poly (ADP-ribose) polymerase (PARP) inhibitors. Clinical trials, including landmark studies, demonstrate that patients with BRCA1/2 mutations or HRD-positive tumors benefit more from PARP inhibitors compared to HRD-negative patients. Identifying tumors with HRD allows oncologists to tailor maintenance and treatment strategies that leverage these vulnerabilities, improving patient survival and quality of life.
A compelling example is the case of a 65-year-old patient diagnosed with stage III high grade serous ovarian cancer, who was found to have a BRCA1 mutation through Omniseq® INSIGHT testing, a comprehensive genomic and immune profiling solid tumor tissue test that uses DNA and RNA next-generation sequencing. Based on testing results and clinical guidelines, she was recommended for PARP inhibitor maintenance therapy following primary chemotherapy and surgery, which has been shown to provide a statistically significant improvement in overall survival. This case highlights the real-world impact of testing that includes germline and somatic with HRD testing in optimizing patient care. Despite its clinical significance, real-world data shows that HRD testing is not widely integrated into routine ovarian cancer diagnostics. A joint analysis by Labcorp and Illumina, presented at the Society of Gynecologic Oncology annual meeting, found that while 84% of patients with ovarian cancer undergo BRCA1/2 testing, less than 50% receive HRD testing. This gap means that many patients who might benefit from targeted therapies are not being identified. By providers integrating HRD testing into their clinical workflows, this allows more patients to receive personalized data driven treatments.
As precision medicine continues to shape the future of oncology, streamlining HRD testing into routine clinical workflows will be essential.”
– Dr. Rebecca Previs, Director of Medical Affairs, Labcorp
Education, awareness and improved access to testing solutions will empower oncologists to make informed treatment decisions, ultimately leading to better outcomes for patients. HRD testing is more than just a diagnostic tool—it is a gateway to precision oncology. Expanding adoption will help healthcare providers offer every eligible ovarian cancer patient the best possible care tailored to their tumor’s biology.