Optimal timing of interval debulking surgery for advanced epithelial ovarian cancer: A retrospective study from the ESME national cohort

Objective. Interval debulking surgery is recommended after 3-4 cycles (standard IDS) of neoadjuvant chemo-therapy (NACT) for epithelial ovarian cancer (EOC) not able to received upfront complete debulking surgery. However, real world practices frequently report performing IDS after >= 5 NAC cycles (delayed IDS). The aim of this work was to evaluate the impact on survival of the number of NACT cycles before IDS. Methods. We identified from a French national database, women with newly diagnosed EOC who underwent IDS from January 2011 to December 2016. Progression free survival (PFS) and overall survival (OS) were com-pared using Cox model with adjustments for confounding factors provided by two propensity score methods: in-verse probability of treatment weighting (IPTW) and matched-pair analysis. Results. 928 patients treated by IDS for which our propensity score could be applied were identified. After a median follow-up of 49.0 months (95% CI [46.0;52.9]); from the IPTW analysis, median PFS was 17.6 months and 11.5 months (HR = 1.42; CI 95% [1.22-1.67]; p < 0.0001); median OS was 51.2 months and 44.3 months (HR = 1.29; CI 95% [1.06-1.56]; p = 0.0095) for the standard and delayed IDS groups. From the matched-pair analysis (comparing 352 patients for each group), standard IDS was associated with better PFS (HR = 0,77; CI 95% [0.65-0.90]; p = 0.018) but not significantly associated with better OS (HR = 0,84; CI 95% [0.68-1,03]; p = 0.0947). Conclusions. Carrying IDS after >= 5 NACT cycles seems to have a negative effect on patients survival. The goal of IDS surgery is complete resection and should not be performed after >3-4 NACT cycles.(c) 2022 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).