The ideal number of neoadjuvant chemotherapy (NACT) cycles prior to interval tumor-reductive surgery (iTRS) for advanced ovarian cancer is poorly defined. We sought to assess survival stratified by number of NACT cycles and residual disease following iTRS in patients with advanced ovarian cancer with partial response (PR) or stable disease (SD) following 3-4 cycles of NACT.

We retrospectively identified patients with advanced high-grade ovarian cancer (diagnosed 2/1/2013 to 2/1/2018) who received at least 3 cycles of NACT and iTRS and had a PR or SD. The population was divided into four groups based on the number of NACT cycles prior to iTRS and residual disease status after (CGR [complete gross residual] or incomplete resection [any amount of residual disease]): 1) 3-4 NACT cycles/CGR, 2) 3-4 NACT cycles/incomplete resection, 3) > 4 cycles/CGR, and 4) >4 cycles/incomplete resection. Overall survival (OS) and progression-free survival (PFS) were estimated using a Kaplan-Meier product-limit estimator and modeled using univariable and multivariable Cox proportional hazards analysis.

The cohort consisted of 265 patients with advanced high-grade ovarian cancer with a median age at diagnosis of 65 years. Most were White (87%), had serous histology (89%), and stage IV disease (57%), with an overall CGR rate of 81%. In a multivariable analysis receipt of >4 NACT cycles was not associated with worse PFS or OS (adjusted hazard ratio [aHR] 1.02, 95% CI 0.74-1.42; aHR 1.12, 95% CI, 0.73-1.72 respectively) than was receipt of 3-4 cycles. Any amount of residual disease was associated with worse PFS and OS regardless of the number of NACT cycles (aHR 1.56, 95% CI 1.09-2.22; aHR 2.38, 95% CI 1.52-3.72 respectively).

Residual disease was associated with worse survival outcomes regardless of the number of NACT cycles in patients with PR or SD after NACT for advanced high-grade ovarian cancer. These data suggest that the ability to achieve CGR should take precedence in decision-making regarding the timing of surgery.