Rosa Damkjær Britton presented HRD data from a large, retrospective cohort of cancer patients with two or more sequential biopsies. The HRD score was calculated am. Telli (LOH, TAI and LSTs) and showed that only a minority (17%) of patients have changes in HRD scores crossing the predefined cut-point of 42 traditionally used for making clinical decisions in regard to therapy choices in eg. ovarian or breast cancer. The study included 24 different diagnoses and implies that repeat testing to confirm previously positive HRD status may not be necessary.
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Examination of Homologous Recombination Deficiency (HRD) status
When patients are referred to the Phase 1 Unit they are offered extensive genomic tumor profiling based on a biopsy from fresh tumor tissue. Genomic tumor profiles contain, amongst other things, an HRD-score. A score ≥42 is considered positive (Telli et al., 2016). Homoglogous recombination deficient cells are unable to repair double-stranded DNA breaks. The faulty DNA-repair mechanism warrants treatment with PARPi or platinum-based chemotherapy.
109 patients from the Phase 1 Unit were retrospectively included Genomic tumor profiles obtained from late-stage cancer patients in the Copenhagen Prospective Personalized Oncology study (Tuxen et al., 20191) at the Phase 1 Unit, Department of Oncology, Rigshospitalet, Copenhagen, Denmark over a 10-year period (August 2013 until April 2023) were retrospectively analyzed.
24 different cancer diagnoses were represented. The most frequent diagnoses were colorectal cancer (n=26, 24%), breast cancer (n=20, 18%) and non-small cell lung cancer (n=17, 16%).
In our cohort 18 patients (17%) changed HRD status from first to last tumor biopsy, with 5 patients having HRD-positive first biopsies and HRD-negative second biopsies. This means, that patients enrolled in clinical trials based on HRD status may not need confirmatory biopsies after intervening treatment.
