Fertility preservation in women with cancer is one of the most debated and current issues in reproductive medicine. The use of lifesaving therapies in these patients negatively affects reproductive function and ovarian reserve, frequently resulting in infertility. 1 One previous study reported that 3% of cancer diagnoses concern patients under the age of 40. 2 Thus, it is important to propose measures for fertility preservation of patients who desire future pregnancies. [3][4][5][6][7] In 2013, the American Society for Reproductive Medicine determined that mature oocyte cryopreservation should no longer be considered an experimental procedure. 8

validated assays to assess HRD are BRCA-mutation (BRCAmut) analysis and genomic instability scores (GIS) designed to detect genomic 'scars' in tumor DNA. However, these tests require large samples and yield non-contributive (NA) in 15% of cases. Bevacizumab and PARPi are approved as maintenance therapy regardless HRD status and the optimal maintenance strategy in case of non-contributive HRD test is a major unmet medical need. We aim to report the clinical characteristics and behavior under chemotherapy of NA HGOC pts. Methodology This is a retrospective analysis of all pts tested for GIS by myChoice HRD Plus assay (Myriad Genetic Laboratories). Pts included presented HGOC with advanced FIGO III/IV diseases and treated according to guidelines. GIS was performed on baseline pretreatment samples, preferably. Platinum-free interval (PFI) was calculated from the date of last platinum-based chemotherapy to the date of relapse. Results 210 patients were recruited: 100 were classified HRD negative (HRD-, score <42), 81 HRD positive (HRD+, score 42) and 29 NA (14%). HRD+ cohort was significantly enriched with BRCAmut pts (21/81 = 27%) compared to HRD-and NA. In the NA cohort, median age was 64 years, 86% had an high-grade serous tumor and 10% presented germinal BRCAmut. With a median follow-up of 39 months, median PFI in the overall population was 19.8 months (95% CI 16.7-24.4). In the HRD+, HRD-and NA cohorts (excluding BRCAmut), median PFI were 34.0 (95%CI 16.7-64.4), 14.6 (95%CI 12.0-20.9) and 37.3 months (95%CI 21.0-NA) respectively (P=0.004). Conclusion Our results suggest that patients with NA GIS results behave like HRD+ tumors harboring high platinumsensitivity and therefore may benefit from PARPi maintenance. The reason for non-contributivity in the first place is unknown and may explain these observations.