Prevalence of homologous recombination deficiency among women with newly diagnosed ovarian, primary peritoneal, and/or fallopian tube cancer: the international HALO study.

OBJECTIVE

The HALO study (NCT04991051) determined the prevalence of homologous recombination deficiency and its associated factors in patients with high-grade serous/endometrioid ovarian, primary peritoneal, and/or fallopian tube cancers across Asia, the Middle East, and Russia.

METHODS

This multinational, cross-sectional, real-world study enrolled adult women with newly diagnosed stage III or IV high-grade serous/endometrioid ovarian, primary peritoneal, and/or fallopian tube cancers. Formalin-fixed paraffin-embedded tumor blocks were collected within 120 days of enrollment. The prevalence of homologous recombination deficiency, high genomic instability score (GIS) without tumor BRCA mutations, and BRCA mutations were evaluated along with patient characteristics. Factors associated with homologous recombination deficiency, high GIS without BRCA mutations, and BRCA mutations were identified using a logistic-regression model.

RESULTS

Of the 734 patients (median [range] age; 59.0 [23.0-89.0] years), most (92.9%) had a primary ovarian tumor, followed by primary peritoneal (4.1%) and fallopian tube cancers (3.0%). Of the tested 662 patients; 56.0% (371) were homologous recombination deficiency-positive (Asia, 52.0%; the Middle East, 52.2%; Russia, 58.5%). Overall, 204 (30.8%) patients had a high GIS without BRCA mutations (Middle East, 23.9%; Russia, 31.9%; Asia, 41.3%), and 167 (25.2%) had BRCA mutations (Asia, 10.7%; Russia, 26.6%; Middle East, 28.3%). Patients with 1 comorbidity versus no comorbidities (96 vs 207, OR 1.54), a family history of genetically-related cancers versus no family history of cancer (82 vs 224, OR 2.64), and contraceptive use versus no history of contraceptive use (47 vs 323, OR 2.04) were more likely to have homologous recombination deficiency.

CONCLUSIONS

This real-world study reported a homologous recombination deficiency prevalence of 56.0% (ranging from 52.0% to 58.5%) across Asia, the Middle East, and Russia. Our results highlight the unmet need to implement guideline-recommended testing and real-world data collection for all patients newly diagnosed with advanced high-grade epithelial ovarian cancer to optimize treatment strategies.