Résumé
Objective: standard interval debulking surgery (IDS) is recommended after 3-4 cycles of neoadjuvant chemotherapy (NAC) for epithelial ovarian cancer (EOC). However, real world practices frequently report IDS after ≥5 NAC cycles (delayed IDS). The aim of this work was to evaluate the impact on survival of the number of NAC cycles before IDS in EOC.Methods: we identified women in the French national Epidemiological Strategy and Medical Economics database with newly-diagnosed EOC who had undergone IDS from January 2011 to December 2016. Overall survival (OS) and progression-free survival (PFS) were compared using a Cox proportional hazards regression model with adjustments for confounding factors provided by two propensity score methods: inverse probability of treatment weighting (IPTW) and matched-pair analysis.Results: we identified 928 patients treated by IDS to whom our propensity score could be applied. In the Cox univariate analysis weighted by IPTW, the median PFS was 17.6 months and 11.5 months (HR=1.42; CI 95% [1.22-1.67]; p<0.0001) and 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, respectively. From the matched-pair analysis (comparing 352 patients for each group), standard IDS was associated with better PFS (HR=1.30; CI 95% [1.10-1.53]; p=0.018) but not significantly associated with better OS (HR=1.20; CI 95% [0.97-1.47]; p=0.0947).Conclusions: performing IDS after ≥5 NAC cycles seems to have a negative effect on the survival of EOC patients. The goal of IDS surgery is complete resection and should not be performed after 3-4 NAC cycles.