111 Evaluation of survival outcomes from delayed cytoreduction surgery following neoadjuvant chemotherapy in advanced epithelial ovarian cancer

Abstract

<h3>Introduction/Background</h3> Optimal timing of cytoreductive surgery following neoadjuvant chemotherapy (NACT) has not been established in the treatment paradigm of advanced epithelial ovarian (EOC) cancer. Traditionally, interval cytoreduction surgery (ICS) is undertaken following 3 cycles of treatment, however in a proportion of patients, surgery is delayed for reasons including incomplete disease response, poor surgical candidacy and anticipated suboptimal tumour resectability. We looked to investigate survival outcomes in advanced epithelial ovarian cancer (EOC) patients with the intention of maximal cytoreduction following neoadjuvant chemotherapy (NACT) with respect to timing of surgery and degree of cytoreduction. <h3>Methodology</h3> A retrospective review was conducted of 572 patients with EOC treated with NACT with the intention of interval cytoreduction surgery (ICS) between 2008 and 2017. Overall survival (OS) and progression-free survival (PFS) outcomes were analysed and compared with patients who only received chemotherapy. Outcome measures were correlated with the number of NACT cycles and amount of residual disease following surgery. <h3>Results</h3> There was no difference in the proportion of patients in whom complete cytoreduction was achieved based on number of cycles of NACT. Median 5-year OS and PFS for patients undergoing cytoreduction after NACT was 38 and 24 months respectively with no significant difference in OS between standard and delayed timing of surgery. Significant OS advantage was associated with patients who had undergone complete cytoreduction compared with those with any macroscopic residual disease (&lt;1 cm residual: HR 1.68; ≥1 cm residual: HR 2.77). <h3>Conclusion</h3> From this study, survival outcomes do not appear to be worse for patients with EOC treated with NACT if cytoreduction surgery is delayed beyond three cycles. In EOC patients, the imperative to achieve complete surgical cytoreduction remains gold standard, irrespective of surgical timing, for best survival benefit. <h3>Disclosures</h3> This work was supported by a research grant from Gynaecological Cancer Research Education and Development Society. Neither author disclose any conflict of interest