Introduction/Background Ovarian cancer is the 8th most common cancer type in the world and the 3rd most common gynecological malignancy and has the highest mortality rate among gynecological cancers. Platinum-based chemotherapy is the routinely recommended treatment method after primary debulking surgery (PDS) in advanced stage ovarian cancer.Time interval from PDS to chemotherapy influences survival in patients with advanced EOC. In this study, we tried to determine the relationship between time to start chemotherapy after PDS and progression-free and overall survival.

Methodology We retrospectively reviewed patients with ovarian cancer who received PDS followed by adjuvant chemotherapy in our hospital between january 2012 and march 2022. Time to chemotherapy was divided into three groups based on the interquartile range (IQR). The patients categorized into three different groups according to time of initiating adjuvant chemotherapy after PDS. Early group (<21 days), intermadiate group( 21–43 days) and late group(>43 days).

Results 46 patients were included and divided into three groups based on time to chemotherapy. The early group had a significantly better median overall survival (n=11, 124 months) compared with intermediate(n=23, 77 months) and late(n=12, 43 months)group ( p=0,006) .Although there was no statistical significance in analyzes intermediate group had beter median PFS (33 months) compared with early (17 months) and late (16 months) group.

Conclusion Our study provides that initiation time of adjuvant chemotherapy after primer debulking surgery is an independent prognostic factor in overall survival.

Disclosures Starting aduvant chemotherapy within six weeks after primer debulking surgery is most suitable for ovarian cancer.